Urosepsis and Bacteriuria in Patients Undergoing TRUS-Guided Prostate Biopsy

A prostate gland biopsy is a test to remove small sample of prostate tissue to be examined under a microscope. A biopsy may be done when a blood test shows a high level of prostate-specific antigen (PSA) or after a digital rectal examination finds an abnormal prostate or a lump. Transrectal ultrasound (TRUS) guided biopsy is a commonly performed procedure for the detection of prostate cancer. It is associated with serious complication like urosepsis. Although the incidence of post-TRUS urosepsis is low, when it occurs it is typically serious and leads to hospitalization. Antibiotics are used prior, during and after the procedure to prevent infections as a result of TRUS biopsy. Ciprofloxacin is being used as antibiotic of choice for a long time. Antibiotic prophylaxis may prevent such complications. This cross-sectional descriptive type of observational study was taken place in Dhaka Medical College Hospital, Dhaka, Bangladesh from January 2010 to December 2011 among purposively selected 70 patients with an aim to determine the urosepsis and bacteriuria after TRUS guided prostate biopsy. Patients attending the Urology OPD in DMCH having of LUTS and other non-specific symptoms were evaluated by history, physical examination including digital rectal examination (DRE) and necessary investigations like serum PSA to identify the potential candidates. Patients with abnormal DRE findings and increased PSA level were included in this study and those who had any painful anal and rectal condition, bleeding diathesis, anticoagulant therapy and any known allergy to lidocaine, previously undergone prostrate biopsy and those who refused to give the informed consent were excluded from this study. Data were collected on variables of interest using a structured case record form. Data were processed and analyzed using Statistical package for social science (SPSS), version 17.0. Frequency of bacteriuria and urosepsis was measured according to urine and blood culture report. Sensitivity pattern was also seen. According to this study, the frequency of bacteriuria and urosepsis was 17.1% and 5.7% respectively. Most common uropathogen was E coli both in urine and blood culture. Organisms (100.0%) were found resistant to ciprofloxacin and amoxicillin. Most of the pathogens were sensitive to tobramycin, gentamycin and cefipime. A potentially dangerous ciprofloxacin resistant organism (ESBL producing E. coli) was found positive in 25.0% of culture positive patients.

Prediction of Thyroid Malignancies by Thyroid Auto Antibodies

Thyroid cancer is the most frequent cancer among endocrine tumors, and account for approximately 1% of all malignancies. Recent literature has suggested an association between autoimmune thyroiditis and papillary thyroid cancer. The aim of the study was to choose the role of preoperative thyroid auto-antibodies as a predictive marker that could distinguish benign and malignant thyroid nodules and any other occult malignancy. This cross sectional study was done from July 2012 to June 2014 in department of Surgery Sir Salimullah Medical College & Mitford Hospital (SSMC&H) in collaboration with department of Otolaryngology SSMC&H, Bangabandhu Sheikh Mujib Medical University, Dhaka Medical College and Bangladesh Medical College of Dhaka city. Inclusion criteria were all patients presenting with thyroid swelling. For this study, 116 patients of thyroid swelling were studied by detailed history, clinical examination, thyroid hormone assay (serum T₃, T₄, TSH), ultrasonogram to detect single or multiple nodules, solid or cystic condition of nodules, thyroid scan to see functional status of gland, FNAC to detect benign or malignant condition preoperatively, thyroid auto antibodies (Tg-Ab and TPO-Ab) and histopathological examinations. FNAC outcomes were compared with anti-thyroid auto antibodies (ATA) and histopathological reports. In this study it showed that out off 89 benign classes 53 were with raised and 36 were with normal anti-thyroid auto anti-bodies (Tg-Ab+TPO-Ab). Among the raised 53 patient only 14(26.41%) were proved malignant in histopathological examination. On the other hand out off 36 normal anti-thyroid auto anti-bodies (Tg-Ab+TPO-Ab), 5(13.88%) became malignant histopathologically. In the cytological malignant group out off 17 patient 8 (47.05%) were with normal anti-thyroid auto anti-bodies (Tg-Ab+TPO-Ab) and 09(52.95%) were with raised anti-thyroid auto anti-bodies (Tg-Ab+TPO-Ab) and all of them were histologically malignant. It was observed that FNAC with high level of anti-thyroid auto anti-bodies (Tg-Ab+TPO-Ab) will be suspicious for malignancy but not statistically significant in this study odds ratio for anti-thyroid auto anti-bodies (Tg-Ab+TPO-Ab) within normal and raised were 0.78(0.501-1.214) and 1.23(0.807-1.89) respectively. In the series sensitivity, specificity, positive predictive value and negative predictive value of thyroid auto antibodies and FNACs were done by the ROC curve. It showed that PPV was highest 96% for FNAC and for Tg-Ab and TPO-Ab it was 27% and 24% respectively. In this study thyroid auto-antibodies were raised in both benign and malignant conditions. TPO-Ab was more raised than Tg-Ab in our country with malignant conditions of thyroid. Thyroid auto anti-bodies could not predict the malignant condition of thyroid. In our study the benign cytology with raised antithyroid auto antibodies showed risk to be malignant outcome in histopathology.

Study on Electrophysiological Findings of Guillain Barre Syndrome Patients Attending the Department of Neurology in BSMMU

Incidence and predominant subtype of Guillain Barre Syndrome (GBS) differ geographically. Electrophysiology has an important role in the early diagnosis and prediction of the prognosis. This study conducted to determine the predominant subtype of Guillain Barre Syndrome in Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh and to compare the nerve conduction study finding between the axonal and demyelinating form of GBS. To analyze the nerve conduction study findings of Guillain Barre Syndrome patients attending the department of Neurology in BSMMU. This observational, descriptive and cross sectional study was carried out in the department of Neurology, BSMMU, Dhaka from July 2014 to June 2016. Considering the inclusion and exclusion criteria, 50 patients recruited as the study population. Then after performing the nerve conduction study, patients classified into three groups: acute inflammatory demyelinating polyneuropathy (AIDP), acute motor axonal neuropathy (AMAN), acute motor and sensory axonal neuropathy (AMSAN). Among the 50 patients that are finally included in the study; about 50%, 42%, 8% had the AIDP, AMAN and AMSAN variety of GBS respectively. Out of all patients, 64% were male and 34% were female. GBS was seen in a wide range of age (18-75 years). In AIDP, maximum clustering of the cases was seen in the elderly population and in the AMAN it was seen in the younger age group. Cerebrospinal fluid (CSF) analysis did not show any significant difference between the AIDP and AMAN variant of GBS. Distal latency prolonged in at least one nerve in all patients with AIDP. In axonal form of GBS (AMAN and AMSAN), the compound muscle action potential (CMAP) amplitude was 80% of the lower limit of the normal in at least two motor nerves. Prolonged F wave latency by >80% of the upper limit of the normal was seen in 40% of the AIDP patients. According to the nerve conduction study, finding- acute inflammatory demyelinating polyneuropathy (AIDP) is the predominant subtype. Although the electrophysiology and the CSF analysis are the important tools for the diagnosis of GBS, classification should not be making based on a distinct finding alone. If all the NCS parameters in multiple nerves tested after one week and within four weeks of onset of symptoms, definite diagnosis is possible in almost all the patients of Guillain Barre Syndrome.

Early Postoperative Parathyroid Hormone Level as a Predictor of Hypocalcaemia after Total Thyroidectomy

Postoperative transient hypocalcaemia is a common squeal after total thyroidectomy usually due to parathyroid insufficiency. Objective of this study is to find out the optimum cut-off value of parathyroid hormone (PTH) level in early postoperative period as a best predictor for hypocalcaemia. This prospective observational study was carried out from July 2013 to July 2014 in the Department of Surgery Sir Salimullah Medical College & Mitford Hospital (SSMC&MH), in collaboration with department of Otolaryngology SSMC&MH, department of Otolaryngology Bangabandhu Sheikh Mujib Medical University (BSMMU) and department of Otolaryngology Dhaka Medical College & Hospital (DMC&H), Dhaka. Total 92 patients were selected those came for total thyroidectomy. PTH was measured at different percentile 6 hours after surgery to find out optimum cut-off point. In 47.5th percentile at 8.02 cut-off point of PTH found with good combination of sensitivity, specificity, positive and negative predictive value, accuracy and it was 83.33%, 91.66%, 90.90%, 84.62% and 91.30% respectively. We found PTH level as a predictor of hypocalcaemia and PTH 8.02pg/ml was the optimum cut-off point to predict hypocalcaemia within 6 hours after total thyroidectomy.

Role of USG-guided fine needle aspiration cytology in the diagnosis of abdominal mass

The present study was carried out with the aims to diagnose abdominal masses by FNAC with the help of ultrasonography guidance and to determine the diagnostic accuracy of FNAC. One hundred consecutive patients were studied during the period from January 2005 to December 2005. Histopathological examination was done to correlate with the cytologic diagnosis. The results of comparative study of USG-guided FNAC and histopathology were significant (P value was <0.001). In USG-guided FNAC, it was found that 64 were malignant tumors, 5 were benign tumors, 28 were inflammatory and 3 were inadequate material. Histopathology of 3 inadequate materials showed 1 was adenoma and 2 were leiomyoma. As a whole test results of USG-guided FNAC were sensitivity 95.52%, specificity 100%, positive predictive value 100%, negative predictive value 91.67% and accuracy 97%. USG-guided FNAC has been proved to be a rapid, reliable and cost-effective diagnostic method.

Use of local anesthesia in transrectal ultrasound guided prostatic biopsy

Transrectal ultrasound (TRUS) guided biopsy of the prostate is the gold standard for detecting prostate cancer. Intraprostatic administration of local anesthesia significantly decreases pain during prostatic biopsy. Transrectal ultrasound guided intraprostatic lidocaine administration along with intrarectally lidocaine gel is a new local anesthesia technique for prostatic biopsy. It was a randomized prospective, comparative, interventional type of the study. A total of 60 patients of age over 55 years included in the study among them 30 patients with transrectal lidocaine gel was in Group I and 30 patients with intraprostatic lidocaine injection with intra rectal gel were in Group II. The mean age was almost identically distributed between the two groups (p=0.668). About 47% of patients in Group I exhibited hard prostate on digital rectal examination (DRE), 33.3% single nodule and 20% multinodule compared to 33.3% of patients in Group II had hard prostate, 26.7% single nodule and 40% multinodule (p=0.236). The mean serum prostate specific antigen (PSA) was significantly higher in Group II than that in Group I (36.7±9.2 vs. 7.5±5.8ng/ml; p=0.007). The mean pain intensity during biopsy was almost two times higher in Group I than in Group II (p<0.001). The present study concludes that the intraprostatic lidocaine injection along with intra rectal lidocaine gel is less painful method and can be considered in all patients undergoing transrectal ultrasound guided prostate biopsy.

Androgens upregulate Cdc25C protein by inhibiting its proteasomal and lysosomal degradation pathways

Cdc25C is a cell cycle protein of the dual specificity phosphatase family essential for activating the cdk1/Cyclin B1 complex in cells entering into mitosis. Since altered cell cycle is a hallmark of human cancers, we investigated androgen regulation of Cdc25C protein in human prostate cancer (PCa) cells, including androgen-sensitive (AS) LNCaP C-33 cells and androgen-independent (AI) LNCaP C-81 as well as PC-3 cells. In the regular culture condition containing fetal bovine serum (FBS), Cdc25C protein levels were similar in these PCa cells. In a steroid-reduced condition, Cdc25C protein was greatly decreased in AS C-33 cells but not AI C-81 or PC-3 cells. In androgen-treated C-33 cells, the Cdc25C protein level was greatly elevated, following a dose- and a time-dependent manner, correlating with increased cell proliferation. This androgen effect was blocked by Casodex, an androgen receptor blocker. Nevertheless, epidermal growth factor (EGF), a growth stimulator of PCa cells, could only increase Cdc25C protein level by about 1.5-fold. Altered expression of Cdc25C in C-33 cells and PC-3 cells by cDNA and/or shRNA transfection is associated with the corresponding changes of cell growth and Cyclin B1 protein level. Actinomycin D and cycloheximide could only partially block androgen-induced Cdc25C protein level. Treatments with both proteasomal and lysosomal inhibitors resulted in elevated Cdc25C protein levels. Immunoprecipitation revealed that androgens reduced the ubiquitination of Cdc25C proteins. These results show for the first time that Cdc25C protein plays a role in regulating PCa cell growth, and androgen treatments, but not EGF, greatly increase Cdc25C protein levels in AS PCa cells, which is in part by decreasing its degradation. These results can lead to advanced PCa therapy via up-regulating the degradation pathways of Cdc25C protein.

Urinary microalbumin as a risk factor for ischaemic stroke

Microalbuminuria (MA), a microvascular irregularity of the blood - urine interface within kidney glomeruli, may reflect the renal sign of global endothelial dysfunction, and has been associated with an elevated risk of serious cardiovascular events including stroke. This case-control study was carried out in the Department of Neurology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh, from January 2008 to December 2009. This relationship appears graded with higher levels of microalbuminuria being independently associated with a greater magnitude of vascular risk over time. We studied 60 patients of ischemic stroke with in 4 weeks of onset of symptoms and performed a case control study for MA by spot urinalysis. The incidence of microalbuminuria was 31.7% of the patients compared with 8.3% of the controls. Of all the traditional risk factors for stroke - age, male gender, hypertension, diabetes, dyslipidemia, smoking showed a positive correlation with the presence of MA (p<0.05). The effect of microalbuminuria and subtypes of ischemic stroke was observed that small vessels stroke (lacunar infract) were more (70%) than large vessels stroke (30%) and effect of microalbuminuria 21.67% higher in small vessels stroke than large vessels stroke. The presence of microalbuminuria appears to independently predict proper clinical outcome following acute stroke.

Optimal scoring of serial change on chest radiography in sarcoidosis

BACKGROUND

The optimal means of quantifying change on chest radiography in sarcoidosis is uncertain. In current guidelines, the role of serial measurement of carbon-monoxide diffusing capacity (DLco) remains undefined and the prevalence of discordance between serial chest radiographic change and pulmonary function tends is unknown.

OBJECTIVE

To identify and explore key uncertainties in the monitoring of sarcoidosis by serial pulmonary function tests and chest radiography.

DESIGN

354 patients with sarcoidosis and concurrent tests (chest radiography and PFTs within three months at baseline, two years and/or four years) were studied. Chest radiographs were assessed by two radiologists for changes in stage and disease extent. Radiographic change and pulmonary function trends were quantified and compared.

RESULTS

Change in radiographic extent of lung disease was always more frequent than change in stage (p < 0.0001) and there was poor agreement between change in stage and change in radiographic extent (Kw = 0.21 at two years; Kw = 0.23 at four years). Change in disease extent on chest radiography was linked to PFT trends on analysis of variance (p < 0.0005 for FEV1, FVC, DLco), whereas change in radiographic stage was not. Changes in gas transfer were often isolated or discordant with other serial data. Discordance between pulmonary function data and chest radiographic data was observed in 50% of cases.

CONCLUSIONS

Change in radiographic extent is more applicable to routine monitoring in sarcoidosis than change in radiographic stage. In future guidelines, the role of serial gas transfer estimation and reconciliation of divergent chest radiographic and functional trends might usefully be addressed.

Steroids up-regulate p66Shc longevity protein in growth regulation by inhibiting its ubiquitination

Background

p66Shc, an isoform of Shc adaptor proteins, mediates diverse signals, including cellular stress and mouse longevity. p66Shc protein level is elevated in several carcinomas and steroid-treated human cancer cells. Several lines of evidence indicate that p66Shc plays a critical role in steroid-related carcinogenesis, and steroids play a role in its elevated levels in those cells without known mechanism.

Methods and Findings

In this study, we investigated the molecular mechanism by which steroid hormones up-regulate p66Shc protein level. In steroid-treated human prostate and ovarian cancer cells, p66Shc protein levels were elevated, correlating with increased cell proliferation. These steroid effects on p66Shc protein and cell growth were competed out by the respective antagonist. Further, actinomycin D and cyclohexamide could only partially block the elevated p66Shc protein level by steroids. Treatment with proteasomal inhibitors, but not lysosomal protease inhibitor, resulted in elevated p66Shc protein levels, even higher than that by steroids. Using prostate cancer cells as a model, immunoprecipitation revealed that androgens and proteasomal inhibitors reduce the ubiquitinated p66Shc proteins.

Conclusions

The data collectively indicate that functional steroid receptors are required in steroid up-regulation of p66Shc protein levels in prostate and ovarian cancer cells, correlating with cell proliferation. In these steroid-treated cells, elevated p66Shc protein level is apparently in part due to inhibiting its ubiquitination. The results may lead to an impact on advanced cancer therapy via the regulation of p66Shc protein by up-regulating its ubiquitination pathway.

Coexpression of EphB4 and ephrinB2 in tumor advancement of uterine cervical cancers

OBJECTIVE

Receptor EphB4 and the corresponding ligand ephrinB2 contribute to tumor growth in various human tumors. This prompted us to study the expression and localization of EphB4 and ephrinB2 in uterine cervical cancers to analyze the EphB4/ephrinB2 functions against clinical backgrounds.

METHODS

Immunohistochemistry and real-time RT-PCR have been done to determine the histoscores and mRNA levels of EphB4 and ephrinB2, respectively, in sixty-two uterine cervical cancer tissue samples. Patient prognoses were analyzed with a 36-month survival rate.

RESULTS

The localization of EphB4 and ephrinB2 was dominantly in the cancer cells of uterine cervical cancers of all cases given. Both the histoscores and mRNA levels of EphB4 and ephrinB2 significantly increased with clinical stages (I<II<III+IV, p<0.001) in uterine cervical cancers. The tumor sizes significantly correlated with the histoscore and mRNA levels of EphB4 and ephrinB2. There were significant differences in histoscores and mRNA levels of EphB4 and ephrinB2 in accordance with lymph node metastasis, but not according to histopathological types. The 36-month survival rates of the 31 patients with high EphB4 and ephrinB2 expression were poor (31% and 19%, respectively), while survival rates for the other 31 patients with low EphB4 and ephrinB2 expression were significantly higher (72% and 73%, respectively).

CONCLUSION

Coexpression of EphB4 and ephrinB2 increased with the disease advancement based on clinical stage, lymph node metastasis, tumor size and with poor patient prognoses. Therefore, EphB4/ephrinB2 expression might work on tumor advancement and coexpression of the Eph/ephrin system may potentiate tumor progression leading to poor survival, thus can be recognized as a novel prognostic indicator in the primary tumors of uterine cervical cancers.

A novel role of Shc adaptor proteins in steroid hormone-regulated cancers

Tyrosine phosphorylation plays a critical role in growth regulation, and its aberrant regulation can be involved in carcinogenesis. The association of Shc (Src homolog and collagen homolog) adaptor protein family members in tyrosine phosphorylation signaling pathway is well recognized. Shc adaptor proteins transmit activated tyrosine phosphorylation signaling that suggest their plausible role in growth regulation including carcinogenesis and metastasis. In parallel, by sharing a similar mechanism of carcinogenesis, the steroids are involved in the early stage of carcinogenesis as well as the regulation of cancer progression and metastatic processes. Recent evidence indicates a cross-talk between tyrosine phosphorylation signaling and steroid hormone action in epithelial cells, including prostate and breast cancer cells. Therefore, the members of Shc proteins may function as mediators between tyrosine phosphorylation and steroid signaling in steroid-regulated cell proliferation and carcinogenesis. In this communication, we discuss the novel roles of Shc proteins, specifically p52(Shc) and p66(Shc), in steroid hormone-regulated cancers and a novel molecular mechanism by which redox signaling induced by p66(Shc) mediates steroid action via a non-genomic pathway. The p66(Shc) protein may serve as an effective biomarker for predicting cancer prognosis as well as a useful target for treatment.

Role of protease activated receptor-2 in lymph node metastasis of uterine cervical cancers

BACKGROUND

Protease activated receptor-2 (PAR-2) has been implicated in cellular proliferation, invasion and metastasis in various tumors. Lymph node metastasis is an important patient prognostic factor for uterine cervical cancers. This prompted us to study the role of PAR-2 in lymph node metastasis of uterine cervical cancers.

METHODS

Thirty patients underwent surgery for uterine cervical cancers. PAR-2 histoscores and mRNA levels were determined by immunohistochemistry and real-time reverse transcription-polymerase chain reaction, respectively. Patient prognosis was analyzed with a 48-month survival rate.

RESULTS

PAR-2 histoscores and mRNA levels significantly (P < 0.05) increased in 12 of 30 metastatic lymph node lesions from the corresponding primary tumor. The 48-month survival rate of the 12 patients with increased PAR-2 levels in metastatic lymph nodes was 42%, while the rate of the other 18 patients with no change in PAR-2 levels was 82%, regardless of histopathological type.

CONCLUSION

PAR-2 might work on lymph node metastasis of uterine cervical cancers, and is considered to be a novel prognostic indicator for uterine cervical cancers.

Expression of IP-10 related to angiogenesis in uterine cervical cancers

Angiogenesis is essential for development, growth and advancement of solid tumours. Interferon-gamma-inducible protein 10 (IP-10) regulates lymphocyte chemotaxis, mediates vascular pericyte proliferation and acts as an angiostatic agent, thus inhibiting tumour growth. This prompted us to study the clinical implications of IP-10 expression related to angiogenesis in uterine cervical cancers. The levels of IP-10 decreased with advancement, and the prognosis of the 30 patients with low IP-10 expression in uterine cervical cancers was poor (66%), whereas the 24-month survival rate of the other patients with high IP-10 expression was 90%. Furthermore, IP-10 levels significantly reverse-correlated with vascular endothelial growth factor (VEGF) levels in uterine cervical cancers. Interferon-gamma-inducible protein 10 might work on suppression of angiogenesis associated with VEGF in advancement, and can be recognised as a prognostic indicator. Furthermore, IP-10 activation might be effective on the suppression of regrowth or recurrence after intensive treatment for advanced cervical cancers.

Clinical implication of estrogen-related receptor (ERR) expression in ovarian cancers

The expression of estrogen receptor (ER)alpha and ERbeta mRNAs did not show any specific manner according to clinical backgrounds in ovarian cancers. On the other hand, the levels of estrogen-related receptor (ERR)alpha mRNA increased with clinical stages regardless of histopathological types in ovarian cancers. However, ERRbeta and ERRgamma mRNA levels were extremely low to determine reliably. ERRalpha can bind to the steroid receptor coactivator family without any ligands, and drive transcription activity of the target genes. The manner of ERR and ER gene expressions might show an independent usage of common cofactors. It is speculated that the up regulation of ERRalpha might be related to advancement of ovarian cancers regardless of plausible interaction via cofactors regulated by ERs. Although ERRalpha is not directly related to growth of ovarian cancer, ERRalpha is a candidate for prognostic factors for ovarian cancer.

Plausible linkage of hypoxia-inducible factor (HIF) in uterine endometrial cancers

OBJECTIVE

Angiogenesis is essential for the development, growth and advancement of solid tumors. Angiogenesis is induced by hypoxia with the angiogenic transcription factor hypoxia-inducible factor (HIF). This prompted us to study the clinical implications of HIF relative to angiogenesis in uterine endometrial cancers.

METHODS

Sixty patients underwent curative resection for uterine endometrial cancers. In the tissue of 60 uterine endometrial cancers, HIF-1alpha, HIF-2alpha and HIF-1beta mRNA levels, and the ratio of angiopoietin (Ang)-2 to Ang-1 (Ang-2/Ang-1) mRNA levels were determined by RT real-time PCR; histochemical scores and localization of HIF-1alpha were determined by immunohistochemistry. Levels of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), thymidine phosphorylase (TP) and interleukin-8 (IL-8) were determined by enzyme immunoassay.

RESULTS

In stage I uterine endometrial cancers, HIF-1alpha histochemical scores and mRNA levels significantly increased with myometrial invasion of uterine endometrial cancers. HIF-1alpha histochemical scores and mRNA levels correlated with the levels of Ang-2/Ang-1 and IL-8.

CONCLUSION

The angiogenic mediator HIF-1alpha, linked to Angs and IL-8, might work on angiogenesis with myometrial invasion of cancer cells in uterine endometrial cancers.

Expression of protease activated receptor-2 related to angiogenesis in tumor advancement of uterine endometrial cancers

Protease activated receptor-2 (PAR-2) is the second member of a novel family of G-protein coupled seven-transmembrane domain receptors. PAR-2 has been reported to be expressed in various tumors and play a vital role in the regulation of cancer cell growth. The purpose of this study was to clarify the roles of PAR-2 in the angiogenic pathway in uterine endometrial cancers. PAR-2 expression was analyzed in 61 uterine endometrial cancer and 15 normal endometrium tissue specimens. PAR-2 histoscores and mRNA levels were determined by immunohistochemistry and real-time RT-PCR, respectively. Microvessel counts were determined by immunohistochemistry for CD31 and factor VIII-related antigen. The localization of PAR-2 was dominant in the cancer cells of endometrial cancer tissues of all cases studied. PAR-2 histoscores highly correlated with PAR-2 mRNA levels in the same tissues (r=0.87, p<0.001). PAR-2 histoscores and mRNA levels both significantly increased in uterine endometrial cancers with clinical stages (I<II<III, p<0.001), dedifferentiation (G1<G2<G3, p<0.001) and myometrial invasion (A<B, p<0.001; B<C, p<0.05) in comparison to normal endometria. There were significant correlations between PAR-2 histoscores and mRNA levels with microvessel counts in uterine endometrial cancers. PAR-2 was upregulated during uterine endometrial cancer progression with dedifferentiation and myometrial invasion. Therefore, PAR-2 might work on tumor advancement of uterine endometrial cancers via angiogenic activity.

Overexpression of ephrinB2 and EphB4 in tumor advancement of uterine endometrial cancers

BACKGROUND

The ligand ephrinB2 and the corresponding receptor EphB4 contribute to tumor growth in various human tumors. This prompted us to study the expression and localization of ephrinB2 and EphB4 in uterine endometrial cancers to analyze the ephrinB2/EphB4 functions against clinical backgrounds.

MATERIALS AND METHODS

We carried out immunohistochemistry and real-time RT-PCR to determine the histoscores and messenger RNA (mRNA) levels of ephrinB2 and EphB4, respectively, in 68 uterine endometrial cancers and 16 normal endometrium tissue samples. Patient prognoses were analyzed with a 60-month survival rate.

RESULTS

The localization of ephrinB2 and EphB4 was dominantly in the cancer cells of uterine endometrial cancer of all cases given. EphrinB2 and EphB4 histoscores were highly correlated with ephrinB2 and EphB4 mRNA levels, respectively (r = 0.864 and r = 0.615, P < 0.01). Both the histoscores and mRNA levels of ephrinB2 and EphB4 significantly increased with clinical stages (I < II < III, P < 0.01), dedifferentiation (G(1) < G(2) < G(3), P < 0.01) and myometrial invasion (A < B < C, P < 0.01 for ephrinB2 and P < 0.05 for EphB4) in uterine endometrial cancers. The 60-month survival rates of the 34 patients with high ephrinB2 and EphB4 expression were poor (59% and 62% respectively), while for the other 34 patients with low ephrinB2 and EphB4 expression, they were significantly higher (85% and 82%, respectively).

CONCLUSIONS

EphrinB2 and EphB4 were overexpressed during the tumor advancement as dedifferentiation and myometrial invasion. Therefore, ephrinB2/EphB4 might work on tumor advancement and may be recognized as a novel prognostic indicator for uterine endometrial cancers.

Expression of cyclooxygenase-2 related to angiogenesis in uterine cervical cancers

Angiogenesis is essential for development, growth and advancement of solid tumors. Cyclooxygenase (COX)-2 is recognized as an angiogenic factor in various tumors. This prompted us to study the clinical implications of COX-2 expression related to angiogenesis in uterine cervical cancers. There was a significant correlation between microvessel counts and COX-2 levels in uterine cervical cancers. COX-2 localized in the cancer cells, but not in the stromal cells of uterine cervical cancer tissues. COX-2 levels increased with advancement, and the prognosis of the 30 patients with high COX-2 expression in uterine cervical cancers was poor (60%), while the 24-month survival rate of the other 30 patients with low COX-2 expression was 90%. Furthermore, COX-2 levels significantly correlated with VEGF levels in uterine cervical cancers. VEGF associated with COX-2 might work on angiogenesis in advancement. Therefore, long-term administration of COX-2 inhibitors might be effective on the suppression of regrowth or recurrence after intensive treatment for advanced uterine cervical cancers.

Plausible linkage of hypoxia inducible factor-1α in uterine cervical cancer

Angiogenesis is essential for the development, growth and advancement of solid tumors. Angiogenesis is induced by hypoxia with angiogenic transcription factor hypoxia inducible factors (HIF). This prompted us to study the clinical implications of HIF relative to angiogenesis in uterine cervical cancers. Although there was no significant difference in HIF-1alpha histoscores and mRNA levels according to histopathological type or lymph node metastasis, HIF-1alpha histoscores and mRNA levels increased significantly with advancing cancer stages. The prognosis of 30 patients with high HIF-1alpha in uterine cervical cancers was poor (73% survival), whereas the 24-month survival rate of the other 30 patients with low HIF-1alpha was 93%. HIF-1alpha histoscores and mRNA levels were correlated with the levels of the angiogenic factors thymidine phosphorylase and interleukin-8, and HIF-1alpha might be linked with these factors in cervical cancer tissue. HIF-1alpha is a candidate for prognostic indicator as an angiogenic mediator in uterine cervical cancer.

Clinical implications of expression of cyclooxygenase-2 related to angiogenesis in ovarian cancer

Angiogenesis is essential for the development, growth and advancement of solid tumors. Cyclooxygenase (cox)-2 is recognized as an angiogenic factor in various tumors. This prompted us to study the clinical implications of cox-2 expression and angiogenesis in ovarian cancer. There was a significant correlation between microvessel counts and cox-2 levels. Cox-2 localized in the cancer cells, but not in the stromal cells of ovarian cancer tissue. Cox-2 levels increased with the advancement, and the prognosis of the 30 patients with high cox-2 expression was extremely poor (33%), while the 24-month survival rate of the other 30 patients, those with low cox-2 expression, was 67%. Furthermore, cox-2 levels significantly correlated with VEGF levels. VEGF associated with cox-2 might work on angiogenesis with advancement. Therefore, long-term administration of cox-2 inhibitors might be effective on the suppression of regrowth or recurrence after intensive treatment for advanced ovarian cancer.

Sex steroid-dependent angiogenesis in uterine endometrial cancers

In general, tumors induce angiogenic factors specific to them, which leads to angiogenesis with advancement. However, angiogenesis in uterine endometrial cancers is complicated because hormone dependency in growth also modifies the angiogenic potential. Therefore, anti-angiogenic therapy for tumor dormancy in uterine endometrial cancers must be thoroughly considered. The upstream of vascular endothelial growth factor (VEGF) gene conserves estrogen-responsive elements. Progesterone primed with estrogen induces thymidine phosphorylase (TP) in uterine endometrium. Sex steroid-dependent VEGF and TP are highly expressed in cases of early stage and well-differentiated uterine endometrial cancers, and basic fibroblast growth factor (bFGF) in cases of advanced and poorly differentiated uterine endometrial cancers. A transcriptional factor for angiogenesis, ETS-1, is linked to VEGF in well-differentiated uterine endometrial cancers, and to bFGF in poorly differentiated uterine endometrial cancers. Therefore, even if dedifferentiation and angiogenic switching occur due to advancement and long-term hormone therapy, the inhibition of ETS-1 along with main angiogenic factors might be an effective strategy to suppress uterine endometrial cancers as a novel anti-angiogenic therapy.

Serum calcium in normal pregnant women

A prospective case-control study was done to determine any difference of serum calcium levels in pregnant women in third trimester and non-pregnant women. Serum calcium levels were determined in 30 normal non-gravid women and 30 women with normal pregnancies during third trimester with age range of 17-35 years. The mean serum calcium levels were found to be significantly lower in normal pregnant woman in third trimester than that of normal non-pregnant controls.

Serum lipid profile in hypertensive and normotensive type II diabetes mellitus patients--a comparative study

A comparative prospective study was done in 10 patients suffering from hypertension with type II diabetes mellitus and 10 patients suffering from type II diabetes without hypertension. The serum Lipid profile was studied on 10 healthy normotensive nondiabetic subject, on 10 patients suffering from hypertension with type II diabetes mellitus and on 10 patients suffering from type II diabetes mellitus without hypertension. In present study a significantly higher level of serum total cholesterol, triglyceride and LDL-Cholesterol concentration were observed in hypertensive type II diabetes mellitus and normotensive type II diabetes mellitus subjects in comparison to control group and serum HDL-cholesterol concentration was significantly lower in both the groups in comparison to healthy control. There was significantly increased level of serum total cholesterol (P < 0.001) and LDL-cholesterol (P < 0.001) in hypertensive type II diabetes mellitus in comparison to normotensive type II diabetes mellitus. Though serum triglyceride level was increased in hypertensive type II diabetes mellitus in comparison to normotensive type II diabetes mellitus, but it was not statistically significant. Serum HDL-cholesterol level was more in normotensive type II diabetes mellitus in comparison to hypertensive type II diabetes mellitus group but it was not statistically significant.

Cancer patterns in Karachi division (1998-1999)

OBJECTIVE

A minimal cancer incidence data for Karachi, the largest city of Pakistan, is being presented here, for the years 1998-1999. The city has a population of 9,802,134; males 5,261,712 (52.6%) and females 4,540,422 (47.4%); census 1998.

METHODOLOGY

A predominantly mixed (passive and active) registration system has evolved in Karachi, the data sources being the hospitals within the Karachi Division. The reported/retrieved cancer data sets at the Karachi Cancer Registry are checked, coded, computerised in an analytical format and analysed.

RESULTS

The incident cancer cases registered in Karachi, during the 2-year period, 1st January 1998 to 31st December 1999 were analysed. The age-standardised incidence rate (ASR) of cancer, all sites was 132.4/100,000 for the males. Cancer of the lung 10.8%; ASR 17.3 was the most frequently recorded malignancy, followed by oral cavity 10.5%; ASR 13.2 and larynx 5.0%; ASR 7.4. The age-standardised incidence rate (ASR) of cancer, all sites was 133.0/100,000 in the females. Cancer of the breast, 32.0%; ASR 40.7 was the most frequently recorded malignancy, followed by oral cavity 8.1%; ASR 11.7 and gall bladder 3.6%; ASR 5.5.

CONCLUSION

The present data has been calculated with an estimated 15-20% probable under ascertainment. Tobacco-associated cancers in Karachi were responsible for 38.3% of the tumours diagnosed amongst the males. Two principal cancers, breast and oral cavity were responsible for 40.1% of the cancers in females. A rare finding was the high incidence of gall bladder cancer in the females. At present it is difficult to determine whether this indicates a genuine high risk or a selection bias. A continuous process of cancer registration to study the trends in the incidence and an adequate cancer control program are possible and essential for Pakistan and can be based on the pattern being practiced in Karachi.

Bioequivalence of two brands of ciprofloxacin 750 mg tablets (Sarf and Ciprobay) in healthy human volunteers

An open, randomized, two-way crossover study was carried out in 28 healthy volunteers at Gulf Pharmaceutical Industries (Julphar), as a joint venture with Saqr Hospital, Ras Al-Khaimah, UAE. The two commercial brands used were Sarf (Julphar, UAE) as test and Ciprobay (Bayer AG, Germany) as reference product. The drug was administered to each subject with 240 mL of water after an overnight fasting in two treatment days separated by a one-week washout period. After dosing, serial blood samples were collected for a period of 24 hr and serum was separated and analyzed for ciprofloxacin using a sensitive, reproducible, and accurate high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection. Various pharmacokinetic parameters, including AUC0-t, AUC0-infinity, Cmax, Tmax, t1/2, and lambdaz, were determined from ciprofloxacin serum concentration-time profiles for both formulations and found to be in good agreement with reported values. The parameters AUC0-t, AUC0-infinity, and Cmax were tested for bioequivalence after log-transformation of data. No significant difference was found based on analysis of variance (ANOVA); the 90% confidence intervals (95.73-107.62%, 94.98-108.26%, 92.80-103.90% for AUC0-t, AUC0-infinity, Cmax, respectively) for the test/reference ratios of these parameters were within the bioequivalence acceptance range of 80-125%. Based on this data, it is concluded that both formulations are bioequivalent and are interchangeable in medical practice.

Hungry for tobacco: an analysis of the economic impact of tobacco consumption on the poor in Bangladesh

OBJECTIVE

To investigate the extent of tobacco expenditures in Bangladesh and to compare those costs with potential investment in food and other essential items.

DESIGN

Review of available statistics and calculations based thereon.

RESULTS

Expenditure on tobacco, particularly cigarettes, represents a major burden for impoverished Bangladeshis. The poorest (household income of less than $24/month) are twice as likely to smoke as the wealthiest (household income of more than $118/month). Average male cigarette smokers spend more than twice as much on cigarettes as per capita expenditure on clothing, housing, health and education combined. The typical poor smoker could easily add over 500 calories to the diet of one or two children with his or her daily tobacco expenditure. An estimated 10.5 million people currently malnourished could have an adequate diet if money on tobacco were spent on food instead. The lives of 350 children could be saved each day.

CONCLUSION

Tobacco expenditures exacerbate the effects of poverty and cause significant deterioration in living standards among the poor. This aspect of tobacco use has been largely neglected by those working in poverty and tobacco control. Strong tobacco control measures could have immediate impact on the health of the poor by decreasing tobacco expenditures and thus significantly increasing the resources of the poor. Addressing the issue of tobacco and poverty together could make tobacco control a higher priority for poor countries.

The impact of duration versus extent of TCR occupancy on T cell activation: a revision of the kinetic proofreading model

The widely accepted kinetic proofreading theory proposes that rapid TCR dissociation from a peptide/MHC ligand allows for stimulation of early but not late T cell activation events, explaining why low-affinity TCR ligands are poor agonists. We identified a low-affinity TCR ligand which stimulated late T cell responses but, contrary to predictions from kinetic proofreading, inefficiently induced early activation events. Furthermore, responses induced by this ligand were kinetically delayed compared to its high-affinity counterpart. Using peptide/MHC tetramers, we showed that activation characteristics could be dissociated from TCR occupancy by the peptide/MHC ligands. Our data argue that T cell responses are triggered by a cumulative signal which is reached at different time points for different TCR ligands.

Bioequivalence evaluation of two brands of cefaclor 500 mg capsules: quantification of cefaclor using solid phase extraction technique

OBJECTIVE

To assess the bioequivalence of two cefaclor 500 mg capsule formulations, and to develop a new high performance liquid chromatographic (HPLC) method using solid phase extraction technique for the quantification of cefaclor in human plasma.

METHOD

An open, randomized, two-way, crossover trial with a one-week washout period in 25 healthy volunteers. The two commercial brands used were Recocef(Julphar, United Arab Emirates) as test and Ceclor(Eli Lilly, UK) as reference product. The drug was administered with 240 mL of water after a 10-h overnight fast. After dosing, serial blood samples were collected for a period of 8 h. Plasma harvested from blood was analysed for cefaclor by a new HPLC method using a solid phase extraction technique. The limit of detection of cefaclor was 17.6 ng/mL; average recovery was 96.5%; the intraday CV was less than 8% and interday CV was less than 13%. Various pharmacokinetic parameters, including AUC0-t, AUC0-infinity, Cmax, Tmax, T1/2, and Kel, were determined from plasma concentrations for both formulations. Statistical analysis (ANOVA and 90% confidence intervals) were applied to AUC0-t, AUC0-infinity and Cmax for bioequivalence evaluation of two brands. The new HPLC method with solid phase extraction circumvented the problem of mixed polarity of cefaclor and facilitated its extraction from the complex plasma matrix while keeping the background free from interference due to endogenous plasma compounds.

RESULTS

No significant difference was observed between the two brands of cefaclor capsules.

CONCLUSION

Recocef was judged bioequivalent to Ceclor and the two products can therefore be considered to be interchangeable in medical practice.

Bioequivalence evaluation of lansoprazole 30-mg capsules (Lanfast and Lanzor) in healthy volunteers

The bioequivalence of two lansoprazole 30-mg capsules was determined in healthy human, adult volunteers after a single dose in a randomized cross-over study. The study was conducted at Pharmaconsult, Flemington Pharmaceutical Corp., New Jersey, USA. Reference (Lanzor, Laboratoires Houde, Paris, France) and test (Lanfast, Julphar, UAE) were administered to volunteers with 240 ml water after overnight fasting. Blood samples were collected at specified time intervals, plasma was separated and analyzed for lansoprazole using a validated HPLC method. The pharmacokinetic parameters AUC(0-t), AUC(0-~), C(max), T(max), T(1/2) and elimination rate constant were determined from plasma concentration-time profile of both formulations and found to be in good agreement with previously reported values. The calculated pharmacokinetic parameters were compared statistically to evaluate bioequivalence between the two brands, using the statistical modules recommended by the Food and Drug Administration. The analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals fell within the acceptable range (80-120%) for bioequivalence. Based on these statistical inferences it was concluded that the two formulations exhibited comparable pharmacokinetic profiles and that Julphar's Lanfast is bioequivalent to Lanzor of Lab. Houde.

T-cell receptor binding kinetics in T-cell development and activation

T-cell activation is of central importance to the generation of an immune response and is also required as part of the host's ability to recognise self proteins. T cells are activated to differing extents by different ligands. Agonist ligands cause the full range of T-cell activation phenotypes – from activation of signalling cascades, to cytokine secretion or target cell killing, to T-cell proliferation. Partial agonists, which can differ from the agonist by as little as a single amino acid residue, can induce some of these responses but not all. Antagonist ligands can disable the signalling of an agonist ligand. These different types of interaction between ligand and T-cell receptor (TCR) also determine the developmental fate of maturing T cells. Much recent work has focused on how the T cell distinguishes between ligands. At least part of the answer lies in the kinetics of its binding to ligand.

T cell receptor binding kinetics and special role of Valpha in T cell development and activation

The kinetics of the interaction between T cell receptor (TCR) and major histocompatibility complex (MHC) has an important role in determining thymocyte-positive and -negative selection in the thymus, as well as in T cell activation. The alpha chain of the TCR is the major player in determining how the TCR fits onto the MHC ligand, and thus has a major role in determining whether a T cell develops as class I or class II restricted. In this article, we summarize recent data from our laboratory and others on the role of polymorphism in the Valpha combining site in determining MHC class restriction, and on kinetic parameters in thymocyte selection.

Bioequivalence evaluation of two brands of cefuroxime 500 mg tablets (Cefuzime and Zinnat) in healthy human volunteers

A bioequivalence study of two oral formulations of 500 mg cefuroxime axetil was carried out in 24 healthy volunteers following a single dose, standard two-treatment cross-over design at the College of Pharmacy, King Saud University, Riyadh, Saudi Arabia, working jointly with King Khalid University Hospital. The two formulations used were Cefuzime (Julphar, United Arab Emirates) as the test and Zinnat (Glaxo Wellcome, England) as the reference product. Both test and reference tablets were administered to each subject after an overnight fasting on two treatment days separated by a 1-week washout period. After dosing, serial blood samples were collected for a period of 8 h. Plasma harvested from blood was analysed for cefuroxime by a sensitive, reproducible and accurate high pressure liquid chromatography (HPLC) method. Various pharmacokinetic parameters including AUC(0-t), AUC(0-infinity), C(max), T(max), T(1/2) and K(el) were determined from plasma concentrations of both formulations and found to be in good agreement with reported values. AUC(0-t), AUC(0-infinity) and C(max) were tested for bioequivalence after log-transformation of data. No significant difference was found based on an analysis of variance (ANOVA); 90% confidence interval for test/reference ratio of these parameters were found within bioequivalence acceptance range of 80-125%. Based on these statistical inferences, it was concluded that Cefuzime is bioequivalent to Zinnat.

Bioequivalence evaluation of lomefloxacin 400 mg tablets (Lomax versus Maxaquin in healthy human volunteers

This study represents the results of a randomized, single dose, two-treatment, two-period crossover study in 18 healthy male volunteers to assess the bioequivalence of two tablets of 400 mg lomefloxacin. The two formulations were: Lomax(R) (Julphar, United Arab Emirates) as the test formulation and Maxaquin(R) (Searle, S.A., UK) as the reference formulation. The study was conducted at the College of Pharmacy, King Saud University, Riyadh, Saudi Arabia, jointly with King Khalid University Hospital, Riyadh, Saudi Arabia. After overnight fasting the two products were administered as a single dose on two treatment days separated by a 1 week washout period. Serial blood samples were collected thereafter, for a period of 48 h. Plasma harvested from blood was analysed for lomefloxacin by a sensitive, reproducible and accurate HPLC method. Various pharmacokinetic parameters including AUC(0-t), AUC(0-infinity), C(max,) T(max), T(1/2), K(elm) and C(max)/AUC(0-infinity) were determined from plasma concentrations for both formulations and found to be in good agreement with reported values. Statistical modules applied to AUC(0-t), AUC(0-infinity) and C(max) revealed no significant difference in the two tested products. Based on these statistical inferences it was concluded that Lomax(R) is bioequivalent to Maxaquin(R).

Allelic exclusion of the T cell receptor alpha-chain: developmental regulation of a post-translational event

Allelic exclusion of the alpha and beta chains of the T cell receptor is maintained by different mechanisms. Exclusion of the beta-chain is primarily by allowing the successful rearrangement of only one of the two beta-chain loci. In the case of the alpha-chain, rearrangement on both chromosomes is very common, as is expression of alpha-chain mRNA and protein encoded by both loci. For the most part, however, functional alpha-chain allelic exclusion is maintained at the cell surface after positive selection in the thymus. The mechanism by which this is accomplished is not yet known, but recent evidence indicates that it is an active process coupled to signalling through the T cell receptor.

Cutting edge: trimolecular interaction of TCR with MHC class II and bacterial superantigen shows a similar affinity to MHC:peptide ligands

Bacterial superantigens such as Staphylococcus aureus enterotoxin A (SEA) are very potent stimulators of T cells. They bind to the Vbeta region of the TCR and to MHC class II, stimulating T cells at nanomolar concentrations. Using surface plasmon resonance measurements, we find that binding between the individual components of the complex (TCR-class II, TCR-SEA, SEA-class II) is very weak, but that the stability of the trimolecular complex is considerably enhanced, reaching an affinity similar to that found for TCR interactions with MHC:peptide ligand. Thus, the potency of SEA in stimulation of T cells is not due to particularly strong affinities between the proteins, but to a cooperative effect of interactions in the TCR-SEA-MHC class II trimolecular complex that brings the kinetics into a similar range to binding of conventional Ags. This range may be the optimum for T cell activation.

Parvovirus infection mimicking systemic lupus erythematosus in a pediatric population

OBJECTIVES

To assess the striking similarities of presentation in a pediatric population between human parvovirus B19 (HPV-B19) infection and systemic lupus erythematous (SLE).

METHODS

Medical records of seven patients (ages 6 to 15) with HPV-B19 infection were reviewed retrospectively.

RESULTS

Six of seven cases presented with a history of malar rash, and all seven had prolonged arthralgias and fatigue. Six of seven had a positive antinuclear antibody (ANA) titer ranging from 1:40 to greater than 1:640, with two patients having antibodies to Scl-70 and others to Sm, RNP, SS-A (Ro), or SS-B (La). The erythrocyte sedimentation rate (ESR) varied from 2 to 68 mm/h. Two patients presented with elevated rheumatoid factor (RF) titers of 24 and 271 IU/mL, respectively. All had elevated IgM antibody levels to parvovirus at the onset, and markedly elevated IgG levels when evaluated throughout their disease course. Over the course of 2 to 3 months, three improved, but the other four continued to have symptomatology for 14, 40, 78, and 120 weeks, respectively. Treatment was symptomatic, and no one developed classic SLE.

CONCLUSIONS

HPV-B19 infection in a pediatric patient group may present with SLE-like symptomatology and positive serology suggestive of SLE. The course of the disease is usually self-limited, though it may be prolonged in some for up to 120 weeks.

Qualitative and quantitative differences in T cell receptor binding of agonist and antagonist ligands

The kinetics of interaction between TCR and MHC-peptide show a general relationship between affinity and the biological response, but the reported kinetic differences between antigenic and antagonistic peptides are very small. Here, we show a remarkable difference in the kinetics of TCR interactions with strong agonist ligands at 37 degrees C compared to 25 degrees C. This difference is not seen with antagonist/positive selecting ligands. The interaction at 37 degrees C shows biphasic binding kinetics best described by a model of TCR dimerization. The altered kinetics greatly increase the stability of complexes with agonist ligands, accounting for the large differences in biological response compared to other ligands. Thus, there may be an allosteric, as well as a kinetic, component to the discrimination between agonists and antagonists.

Posttranslational regulation of TCR Valpha allelic exclusion during T cell differentiation

We have previously shown that phenotypic allelic exclusion of TCR alpha-chain is functional only in mature thymocytes. A significant proportion of immature thymocytes (TCRlow) express more than one cell surface alpha-chain, but mature thymocytes (TCRhigh) show phenotypic allelic exclusion and express only a single alpha-chain. We have analyzed thymocytes for both surface and intracellular alpha-chain expression and find that the majority of mature thymocytes express a second alpha-chain intracellularly. This result is predicted by a model in which the developmentally regulated allelic exclusion of the TCR alpha-chain is caused by competition between alpha-chains for the beta-chain rather than by models in which one alpha-chain is down-regulated or in which selection favors cells with only a single alpha-chain species. Changes in the relative amounts of alpha- and beta-chains available for pairing may therefore allow competition between the two alpha-chains for the beta-chain. Peripheral T cells also frequently express second alpha-chains in the cytoplasm (18-27%), despite a rather low frequency of dual alpha-chain expression on the cell surface (2-4%). The frequency of nonsurface expressed alpha-chains is reduced somewhat compared with thymocytes, indicating that an additional level of control of allelic exclusion operates during the maturation of peripheral T cells.

Partial-area method in bioequivalence assessment: naproxen

Regulatory authorities require demonstration of bioequivalence through comparisons of different pharmacokinetic parameters, the area under the plasma concentration-time curve (AUC), the maximum plasma concentration (Cmax), and the time to reach peak concentration (Tmax). The applicability and validity of regulatory requirements have been widely criticized on statistical and clinical relevance grounds. For most noncomplicated absorption models, the AUC correlates well with the extent of absorption. However, in nonlinear models of absorption, in mechanisms involving recycling of drugs, and for drugs with long half-life, the use of total AUC (from zero to infinity) can give erroneous and clinically irrelevant results since the area is mostly determined by elimination phase or by recycling. The calculation of total AUC also involves prolonged sampling, adding to the cost and risks associated with bioequivalence studies. The use of Cmax or Tmax as a measure of rate of absorption, to correlate with clinical relevance, is widely criticized on logical, technical, and statistical grounds. For drugs used on a multiple-dose basis, Cmax and Tmax evaluations become redundant since the average plateau concentration is not affected by these parameters. To resolve the drawbacks in the traditional methodology of bioequivalence evaluation, the use of partial areas in lieu of total AUC, Tmax, and Cmax is suggested. This study investigates the logic and robustness of the partial-area method in establishing bioequivalence. We conclude that the 5h AUC is a more relevant parameter to establish naproxen bioequivalence than AUCinf. We recommend against using symmetrical confidence intervals and report excellent agreement among several methods of calculating confidence intervals, probability values, and nonparametric tests. We suggest that a single-point short-term AUC is a better indicator of the bioequivalence of generic products than the total AUC, Cmax, and Tmax as required currently by the regulatory authorities.

T-cell-receptor affinity and thymocyte positive selection

Development of thymocytes involves two distinct outcomes resulting from superficially similar events. Recognition by thymocytes of major histocompatibility complex (MHC) proteins plus peptides leads to their rescue from apoptosis (positive selection), and recognition of antigenic peptide induces cell death (negative selection). Antigen analogues, and sometimes low concentrations of antigenic peptide, induce positive selection; such analogues are often antagonists of mature T-cell clones. Various models seek to explain how recognition of different peptide/MHC complexes leads to such different outcomes: quantitative models relate response to the affinity, avidity or kinetics of T-cell-antigen receptor (TCR) binding, whereas qualitative models require conformational or spatial changes in the TCR or associated molecules to modulate signal transduction. We have used surface plasmon resonance to measure the kinetics of TCR interactions with positively and negatively selecting ligands to distinguish between these models, and find that affinity correlates to the outcome of selection. A 'window' of affinity resulting in positive selection extends over a 1-log range starting threefold below the affinity for negative selection.

Dose dependent pharmacokinetics of naproxen in man

The pharmacokinetics of one of the most widely used non-steroidal antiinflammatory drugs, naproxen, were studied in 28 healthy human volunteers at the two most commonly used dose levels, viz., 250 mg and 500 mg, in a cross-over design. The plasma levels of naproxen were analysed by a modified high-pressure liquid chromatography method. The plasma concentrations at higher doses were not proportional to dose, indicating a non-linearity in the pharmacokinetics at the dose levels studied; this finding is new since earlier studies had studied only higher doses and assumed that at lower doses the pharmacokinetics would be linear. There was, however, no significant difference in the elimination half-life (rate constant), time to reach peak concentration (Cmax), mean residence time (MRT), or area under first moment curve (AUMC). The clearance and distribution volume of naproxen were substantially increased at higher dose resulting in statistically lower proportional concentration and the total area under the curve (AUC). These observations are explained on the basis of a change in the plasma protein binding resulting in more free naproxen available for quicker clearance and wider penetration into tissues. These findings have several important clinical implications for the long-term use of naproxen as an antiarthritic drug. It is proposed that the clinical efficacy of naproxen can be increased and side-effects reduced by giving it in small divided doses instead of large doses.

Enzymatic activities of some snake venoms from families Elapidae and Viperidae

Alkaline phosphomonoesterase, phosphodiesterase, L-amino acid oxidase, hyaluronidase, 5'-nucleotidase, arginine ester hydrolase, phospholipase A2 and proteinase activities were determined in eight snake venoms, including three from sea snake, of families Elapidae and Viperidae from Pakistan. The species includes three sea snakes Hydrophis cyanocinctus, Enhydrina schsitosa, Microcephalophis gracilis gracilis and two land snakes Naja naja naja, Bungarus caeruleus of family Elapidae while three land snakes Vipera russelli russelli, Echis carinatus and Eristocophis macmahoni of family Viperidae. The venoms of family Elapidae are characterized by low levels to traces of proteinase, L-amino acid oxidase and arginine ester hydrolase activities with the exception of Naja naja naja and a moderate to high levels of phospholipase A2 activities. The venoms of family Viperidae, on the other hand, are characterized by the presence of moderate to high levels of 5'-nucleotidase, proteinase, phosphodiesterase and phosphomonoesterase activities.

Allelic exclusion of mouse T cell receptor alpha chains occurs at the time of thymocyte TCR up-regulation

We report a detailed analysis of TCR V alpha and V beta chain expression on immature versus mature thymocytes of normal, TCR beta-transgenic, and TCR alpha-hemizygous mice. Chain pairing between TCR V alpha and V beta chains is random on immature thymocytes, but individual chain pairs are selected in mature thymocytes. This indicates that V alpha-V beta chain pairing preferences are determined during thymic selection, and not as a result of structural constraints. Dual V alpha chain expression is found frequently on immature, but not mature thymocytes. It is not found in TCR alpha-hemizygous mice, showing that cell surface expression of dual alpha chains is caused by lack of allelic exclusion in immature thymocytes. Down-regulation of one of the alpha chains occurs concurrently with differentiation from TCRlo, CD69- to TCRhi, CD69+ phenotype, suggesting that it is associated with positive selection of the functional TCR.