Is penicillamine transported into cells via system ASC, an amino acid transporter?
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Injection of an Ascaris suum extract (Asc) affects both the humoral and cellular immune responses to unrelated antigens when it is co-administered with these antigens. In the present study we evaluated the effect of Asc on macrophage activation in the early phase of Mycobacterium bovis BCG (Pasteur strain TMCC 1173) infection in C57Bl/6 mice. C57Bl/6 mice were injected intraperitoneally (ip) with 0.1 mg BCG (BCG group) or BCG plus 1 mg Asc (BCG + Asc group). The peritoneal exudates were obtained at 2, 7 and 14 days after infection. The numbers of IFN-gamma-secreting cells were assessed by the ELISPOT assay. Nitric oxide (NO) production was measured by the Griess method and by the evaluation of NADPH diaphorase activity in the peritoneal exudates. The administration of Asc extract increased NADPH diaphorase activity (2 days: control = 0, BCG = 7%, BCG + Asc = 13%, and Asc = 4%; 7 days: control = 4, BCG = 13%, BCG + Asc = 21%, and Asc = 4.5%) and TNF-alpha levels (mean +/- SD; 2 days: control = 0, BCG = 169 +/- 13, BCG + Asc = 202 +/- 37, and Asc = 0; 7 days: control = 0, BCG = 545 +/- 15.5, BCG + Asc = 2206 +/- 160.6, and Asc = 126 +/- 26; 14 days: control = 10 +/- 1.45, BCG = 9 +/- 1.15, BCG + Asc = 126 +/- 18, and Asc = 880 +/- 47.67 pg/ml) in the early phase of BCG infection. Low levels of NO production were detected at 2 and 7 days after BCG infection, increasing at 14 days (mean +/- SD; 2 days: control = 0, BCG = 3.7 +/- 1.59, BCG + Asc = 0.82 +/- 0.005, Asc = 0.48 +/- 0.33; 7 days: control = 0, BCG = 2.78 +/- 1.54, BCG + Asc = 3.07 +/- 1.05, Asc = 0; 14 days: control = 0, BCG = 9.05 +/- 0.53, BCG + Asc = 9.61 +/- 0.81, Asc = 10.5 +/- 0.2 (2 x 10(6)) cells/ml). Furthermore, we also observed that Asc co-injection induced a decrease of BCG-colony-forming units (CFU) in the spleens of BCG-infected mice during the first week of infection (mean +/- SD; 2 days: BCG = 1.13 +/- 0.07 and BCG + Asc = 0.798 +/- 0.305; 7 days: BCG = 1.375 +/- 0. 194 and BCG + Asc = 0.548 +/- 0.0226; 14 days: BCG = 0.473 +/- 0.184 and BCG + Asc = 0.675 +/- 0.065 (x 10(2)) CFU). The present data suggest that Asc induces the enhancement of the immune response in the early phase of BCG infection.
Uptake of L-[1-(14)C]ascorbic acid (Asc) of 12.5-200 microM for 1 h into bovine aortic endothelial BAE-2 cells grown to confluence was as low as 43-64% (per cell) of uptake into the cells grown to nearly one-fourth confluence. [14C]Asc undergoing transmembrane uptake was concentrated and accumulated in the cell less efficiently ([Asc]in/ex = 8-13) at confluence than at subconfluence ([Asc]in/ex = 15-24). The declined Asc uptake at confluence is attributable to slowdown of the cell cycle, because a similar decrease in [Asc]in/ex was shown by subconfluent cells precultured in serum-insufficient medium, resulting in an increase in G1 phase and concurrent decreases in S and G2 + M phase distributions as determined by flow cytometry. [1-(14)C]Dehydroascorbic acid (DehAsc) was taken up and accumulated as Asc, after metabolic reduction, without detectable DehAsc. The [Asc]in/ex values for DehAsc at confluence were as low as 15-69% of those at subconfluence in contrast to the values as retentive as 62-75% for Asc, suggesting the moderate control of Asc uptake against slowdown of the cell cycle. At either confluence or subconfluence, dose-dependence for DehAsc uptake was more marked than for Asc uptake as shown by an uphill slope in a curve of doses versus [Asc]in/ex for DehAsc in contrast to a downhill slope for Asc, suggesting the moderate control for Asc uptake against fluctuation of the dose. Increasing of coexistent glucose of 5 mM to 20-40 mM, plasma concentrations in diabetic patients, declined DehAsc uptake to 46-48%, which was less moderately controlled than Asc uptake retained to 59-73%. Asc uptake did not compete with DehAsc uptake, suggesting different transporter proteins for Asc and DehAsc. Thus, Asc uptake into the aortic endothelial cells is more moderately controlled against slowdown of the cell cycle, decreasing of the extracellular concentrations or increasing of coexistent glucose than DehAsc uptake, suggesting a homeostatic advantage of Asc over DehAsc in terms of retention of intracellular Asc contents within a definite range.
BACKGROUND: A survey of the distribution of human papillomavirus (HPV) types across the spectrum of cervical cytologic categories defined by the Bethesda 2001 guidelines was conducted with the objective of examining how HPV detection by polymerase chain reaction (PCR) analysis may benefit the management of patients who have abnormal Papanicolaou (Pap) test results. METHODS: DNA samples from women with no intraepithelial lesion or malignancy (NLM) (n = 300 samples); atypical squamous cells of undetermined significance (ASC-US) (n = 200 samples); low-grade squamous intraepithelial lesion (LSIL) (n = 200 samples); atypical squamous cells, cannot rule out high-grade squamous intraepithelial lesion (ASC-H) (n = 200 samples); and high-grade squamous intraepithelial lesion (HSIL) (n = 200 samples) were tested for HPV using a modified general primer (GP)5+/GP6+ PCR assay and dot-blot hybridization with type-specific oligonucleotide probes (PCR assay analytical sensitivity: 1-100 copies of HPV, depending on the HPV type, in a background of 100 ng human DNA). RESULTS: HPV was detected in 27% of NLM samples, in 89.5% of ASC-US samples, in 97.5% of LSIL samples, in 93% of ASC-H samples, and in 96.5% of HSIL samples. Thirty-seven different HPV types were identified in total. One or more of 13 high-risk (HR) HPV types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68) were detected in 53% of samples that were diagnosed as ASC-US (59.0% of patients younger than age 30 yrs; 45.5% of patients age 30 yrs and older), in 55.5% of samples that were diagnosed as LSIL (60.0% of patients younger than age 30 yrs; 44.0% of patients age 30 yrs and older), in 80% of samples that were diagnosed as ASC-H, and in 87.5% of samples that were diagnosed as HSIL (P < 0.001). HPV-16 was detected in 17.5% of ASC-US samples, in 15.5% of LSIL samples, in 48.5% of ASC-H samples, and in 49.0% of HSIL samples (P < 0.001). Among abnormal smears, HR HPV was significantly more common in women younger than age 30 years compared with women age 30 years and older (P < 0.002). Follow-up biopsy data were obtained for 359 patients. A "benign" biopsy result was recorded for 47 of 64 women (73.5%) with ASC-US, 30 of 66 women (45.5%) with LSIL, 39 of 87 women (45.0%) with ASC-H, and 26 of 142 women (18.0%) with HSIL and was most common in women age 30 years and older (P < 0.0001). Cervical intraepithelial neoplasia (CIN) Grade I (CIN-I) was found in 14.0% of women with ASC-US, in 39.5% of women with LSIL, in 8.0% of women with ASC-H, and in 7.0% of women with HSIL. CIN-II was diagnosed in 9.5% of women with ASC-US, in 13.5% of women with LSIL, in 19.5% of women with ASC-H, and in 24.0% of women with HSIL. CIN-III was identified in 2 women (3.0%) with ASC-US, in 1 woman (1.5%) with LSIL, in 24 women (27.5%) with ASC-H, and in 71 women (50.0%) with HSIL. CONCLUSIONS: HR HPV testing by PCR of samples diagnosed according to the Bethesda 2001 guidelines may benefit the management of patients with ASC-US or patients with LSIL, especially among women age 30 years and older, by allowing exclusion from referral for biopsy of women who are negative for HR HPV types. However, the small numbers of women who had CIN-III detected after a diagnosis of ASC-US or LSIL limited the assessment of test sensitivity.
This article covers several of the emerging issues related to ASCs, the anti-kickback statute and safe harbors, other regulations and relevant court decisions. The ASC Safe Harbors raise several concerns either because they are vague, silent, or provide little guidance as to their requirements. Perhaps the most challenging question under the ASC safe harbor relates to the handling of physicians who do not comply with the various safe harbor tests. As discussed, an ASC should address early on whether physicians who fail to meet or comply with the safe harbor will be redeemed from the venture. In redeeming such physicians, it is important to consider whether the company's operating agreement or shareholder agreement provides for redemption upon such event and whether the redemption will lead to litigation or compliance risks. Along the same lines, since it is illegal to provide any form of value in exchange for referrals under the anti-kickback statute, share sales at below fair market value may be viewed as an illegal kickback in exchange for referrals. Thus, in terms of adding physician owners, a number of guidelines should be followed. An ASC should also carefully consider situations in which it waives or discounts co-payments or deductibles. The safest course for a provider remains to collect the entire co-payment and deductible amounts from patients. Moreover, in the case of Medicare and Medicaid patients, an ASC should never waive or discount co-payments and deductibles unless the patient demonstrates financial hardship. Either way, such a waiver or discount should only be in accord with an applicable charity care or discount policy. A new issue involving the anti-kickback statue, state and federal self referral laws, and Medicare regulations, has gained attention as ASCs are increasingly finding themselves approached by third party vendors to enter into an arrangement, where the vendor owns the equipment and bills a third-party payor for the technical component of the procedure performed with the equipment, and the vendor then pays the ASC a fee for its lease of ASC space to house the equipment. These types of relationships can raise several legal compliance concerns. An ASC should understand that the arrangement could jeopardize its state ASC license and its Medicare certification even though the arrangement does not involve Medicare certified procedures or Medicare patients. Furthermore, this type of business venture might not comply with state and federal self referral laws. ASCs are also increasingly facing situations where a provider performs a procedure for which there is no facility charge for the ASC, but the physician is receiving a professional fee from Medicare. In this situation, ASCs should implement a policy, similar to the example provided in this article, to avoid even the appearance of providing an inducement or reward for referrals of Medicare or Medicaid business by requiring physicians to pay the Center a fee, consistent with fair market value, for the use of the Center for non-Covered Procedures or for performing multiple procedures within the same operative session. Lastly, as touched upon by this article, in the joint venture context, ASCs must take into account several guidelines in order to steer clear from risks associated with tax-exempt entities as an investor and antitrust price fixing issues. Whether a joint venture, of which a tax exempt entity is an investor, is deemed organized and operated in furtherance of the charitable purposes of a tax-exempt partner as set forth in Section 501(c)(3) of the Code depends on the facts and circumstances of each case. Generally, a joint venture will satisfy the guidelines if the tax-exempt investor in the joint venture retains sufficient control over the joint venture to ensure that the joint venture furthers the charitable purposes of the tax-exempt investor and adequately serves the community. In the ASC physician hospital joint venture arena, the principal antitrust concern relates to potential claims of price fixing. Where a hospital is a partner in a joint venture, the hospital and joint venture must take action to assure that the pricing and negotiations of the hospital and the ASC are handled separately. In all of these situations, ASCs and their investors must pay close attention and stay current of the safe harbor concepts, as well as the other regulations, guidelines, and court decisions discussed in this article in order to avoid potential regulatory and litigation risks.
BACKGROUND: Current guidelines recommend colposcopy rather than high-risk human papillomavirus (HPV) testing for the evaluation of abnormal cervical cytology interpreted as "atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion" (ASC-H) based on data from the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesion (ASCUS/LSIL) Triage Study (ALTS), which indicated that ASC-H had a significantly greater frequency of high-risk HPV positivity and underlying high-grade squamous intraepithelial lesions (HSIL) compared with ASCUS. The cytologic interpretations in the ALTS were expert consensus diagnoses rather than routine, single-pathologist readings. METHODS: The authors conducted a comparative analysis of Hybrid Capture 2 high-risk HPV positivity and frequency of histologically diagnosed HSIL for ASC-H and ASCUS to evaluate the performance of ASC-H as a cytologic interpretation subcategory and the potential utility of HPV testing for colposcopy triage of ASC-H in routine practice. RESULTS: Sixty-four of 96 patients with ASC-H (66.7%) were HPV-positive compared with 484 of 1079 patients with ASCUS (44.9%). Among the patients who had histologic follow-up, HSIL was identified in 18 of 45 patients (40.0%) with HPV-positive ASC-H compared with 27 of 266 patients (10.2%) with HPV-positive ASCUS (P < 0.0001) and 1 of 22 patients (4.5%) with HPV-negative ASC-H (P = 0.003); the latter result was similar to the finding of HSIL in 5 of 85 patients (5.9%) with HPV-negative ASCUS. The frequency of HPV-positive ASC-H in the current study (67%) was lower than that obtained in the ALTS for ASC-H (86%) but higher than that for ASCUS in both this study (45%) and in the ALTS (51% for all ASC; 63% for ASCUS, equivocal for LSIL). Underlying HSIL was detected in a similar percentage of patients with HPV-positive ASC-H in this study and in the ALTS (41%). CONCLUSIONS: The greater frequency of HPV positivity and the significantly increased risk of underlying HSIL for ASC-H compared with ASCUS indicated that ASC-H category utilization and performance are appropriate in this routine clinical practice setting. The lower frequency of HPV positivity for ASC-H compared with the ALTS data and the similar low risk of HSIL in HPV-negative ASC-H and HPV-negative ASCUS indicate that HPV testing for triage of ASC-H in routine practice has the potential to reduce the number of women who are referred for colposcopy without an increased risk of failure to detect HSIL among HPV-negative women, similar to its triage role for ASCUS.
We identified a novel amino acid transporter designated Asc-2 (for asc-type amino acid transporter 2). Asc-2 exhibited relatively low but significant sequence similarity to the members of the heterodimeric amino acid transporters. The cysteine residue responsible for the disulfide bond formation between transporters (light chains) and heavy chain subunits in the heterodimeric amino acid transporters is conserved for Asc-2. Asc-2 is, however, not colocalized with the already known heavy chains such as 4F2 heavy chain (4F2hc) or related to b(0,+) amino acid transporter (rBAT) in mouse kidney. Because Asc-2 solely expressed or coexpressed with 4F2hc or rBAT did not induce functional activity, we generated fusion proteins in which Asc-2 is connected with 4F2hc or rBAT. The fusion proteins were sorted to the plasma membrane and expressed the function corresponding to the Na(+)-independent small neutral amino acid transport system asc. Distinct from the already identified system asc transporter Asc-1 which is associated with 4F2hc, Asc-2-mediated transport is less stereoselective and did not accept some of the high affinity substrates of Asc-1 such as alpha-aminoisobutyric acid and beta-alanine. Asc-2 message was detected in kidney, placenta, spleen, lung, and skeletal muscle. In kidney, Asc-2 protein was present in the epithelial cells lining collecting ducts. In the Western blot analysis on mouse erythrocytes and kidney, Asc-2 was detected as multiple bands in the nonreducing condition, whereas the bands shifted to a single band at lower molecular weight, suggesting the association of Asc-2 with other protein(s) via a disulfide bond. The finding of Asc-2 would lead to the establishment of a new subgroup of heterodimeric amino acid transporter family which includes transporters associated not with 4F2hc or rBAT but with other unknown heavy chains.
OBJECTIVE: To evaluate the criteria for diagnosis of atypical squamous cells (ASC) and its two subtypes: undetermined significance ASC (ASC-US) and atypical squamous cells-cannot exclude high-grade intraepithelial lesion (HSIL, ASC-H) defined in 2001 the Bethesda system (TBS). METHOD: One thousand one hundred and eighty six pap smears and liquid-based thin-layer preparations with diagnosis of atypical squamous cells of undetermined signification (ASCUS) according to TBS 1991 criteria, were re-classified by a cytopathologist using TBS 2001 criteria. RESULTS: The cytologic diagnosis according to TBS 2001 criteria was: negative in 285 cases (24.0 %), ASC-US in 627 cases (52.9%), ASC-H in 254 cases (21.4%), low-grade intraepithelial lesion (LISL) in 16 cases (1.3%), and HISL in 4 cases (0.3%), respectively. Out of 1186 cases, 168 received histological examination. Cervical intra-epithelial neoplasia (CIN) II-III were diagnosed in 18.9 % of patients with ASC-H, 5.2% of patients with ASC-US, and 14.3% of patients with ASCUS defined by using TBS 1991 criteria, respectively (P < 0.05). During the follow-up of 6 months, 4 cases of ASC-US changed to LSIL, one ASC-US changed to HSIL, 2 ASC-US changed to LSIL, and 2 ASC-US to HSIL. CONCLUSIONS: New classification of ASC recommended by 2001 TBS has apparent clinical significance. Colposcopically directed cervical biopsy should be performed immediately if ASC-H is diagnosed. In ASC-US patients, checking of cervical smear in an interval of 3 approximately 6 months is necessary. It is suggested to use ASC-US and ASC-H instead of ASCUS in cytological diagnosis.