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T S Thomas

Publications and source records attributed to T S Thomas.

At least 19 recordsLinked to original sources
PubMed2002

A male genital tract-specific carbohydrate epitope on human CD52: implications for immunocontraception.

The identification of unique sperm surface epitopes that are not expressed or exposed in the female reproductive tract is a key element in the development of antibody-based contraceptives. Western blotting and immunohistochemistry were performed to define the tissue distribution of the S19 epitope, which has been proposed as a target for immunocontraception. S19 is an IgG1 murine monoclonal antibody (mAb) directed to an N-linked carbohydrate epitope on a 15-25 kDa glycoprotein, sperm agglutination antigen-1 (SAGA-1), containing a peptide core identical to that of the lymphocytic surface protein CD52. In this study, the S19 epitope was shown to be absent from human lymphocytes, demonstrating a distinction between this epitope and the CAMPATH epitope that is recognized by an antibody against the terminal tripeptide and GPI-anchor of CD52. Further tissue specificity analysis identified the S19 epitope in the epithelium of the human epididymis and vas deferens, as well as on both epididymal and ejaculated spermatozoa. In contrast, the S19 epitope was absent in the five human female reproductive tract and 18 other somatic tissues tested. These results support the use of the S19 epitope as a contraceptive immunogen and the suitability of the S19 mAb as an intravaginal contraceptive. To test the agglutinating activity of the S19 mAb in a formulation designed for vaginal use, S19 mAb were bound to the surface of Novasomes, a multilamellar liposome delivery vehicle. S19-Novasome formulations agglutinated human spermatozoa and were as effective as unbound S19 mAb, demonstrating the feasibility of spermistatic contraceptives targeted to the male reproductive tract specific carbohydrate epitope.

Antibodies, Monoclonal↗
PubMed2001

Gamete retrieval in terminal conditions.

There has been a growing interest and requests by patients facing intensive chemotherapy or surgically ablative procedures for gamete retrieval and preservation for future procreative efforts. There are technical difficulties in this area but little ethical discomfort. More troubling are the issues that arise with a terminally ill, incapable patient-one who is in a persistent vegetative state or who is declared brain dead or who is neurologically devastated with no hope for recovery, but not yet in either of the above states-or with a person who has suddenly died. In these cases, the surviving spouse, partner, or family members may request gamete retrieval for future reproductive efforts. Discussion of this topic within the Ethics Consultation Service at the University of Virginia demonstrated a need for development of insight derived from facts and ethical deliberation to help formulate a policy that would apply to such cases. A group was assembled with the expertise to explore the issue and to help formulate a policy that could be suggested for adoption by the hospital administration. The group consisted of a urologist with experience in sperm retrieval from terminally ill patients; the director of the laboratory supporting the assisted reproductive facility in the Department of Obstetrics and Gynecology; the chairperson of the Ethics Consultation Service (who is also a neonatologist); and 2 members of the Ethics Consultation Service, one a genetic counselor and the other an obstetrician-gynecologist with a master's degree in biomedical ethics. Current literature was reviewed, the expertise of the urological member and the reproductive laboratory director was explored, and the insight of the members of the Ethics Consultation Service was added. We explored the technical aspects of both male and female gamete retrieval and preservation and the reproductive potential of these stored gametes. We present a review of the current literature on both the technical and ethical aspects of the topic. Finally, we present a policy that we deem acceptable for adoption and that should be of value to other practitioners and facilities as they contemplate facing requests for gamete retrieval.

Advance Directives↗
PubMed2001

Impact forces and neck muscle activity in heading by collegiate female soccer players.

Three soccer header types (shooting, clearing and passing) and two heading approaches (standing and jumping) were manipulated to quantify impact forces and neck muscle activity in elite female soccer players. The 15 participants were Division I intercollegiate soccer players. Impact forces were measured by a 15-sensor pressure array secured on the forehead. The electromyographic (EMG) activity of the left and right sternocleidomastoid and trapezius muscles was recorded using surface electrodes. Maximum impact forces and impulses as well as the EMG data were analysed with separate repeated-measures analyses of variance. Impact forces and impulses did not differ among the header types or approaches. Higher values were found for jumping versus standing headers in the mean normalized EMG for the right sternocleidomastoid. In addition, the integrated EMG was greater for the right sternocleidomastoid and right and left trapezius (P < 0.05). The sternocleidomastoid became active earlier than the trapezius and showed greater activity before ball contact. The trapezius became active just before ball contact and showed greater activity after ball contact. The increased muscle activity observed in the neck during the jumping approach appears to stabilize the connection between the head and body, thereby increasing the stability of the head-neck complex.

Adult↗
PubMed2001

Differential nuclear localization of the cancer/testis-associated protein, SPAN-X/CTp11, in transfected cells and in 50% of human spermatozoa.

Cancer-testis antigens (CTAs) represent potential targets for cancer immunotherapy because these proteins are widely distributed in tumors but not in normal tissues, except testes. In this paper, we identify homology of the CTA CTp11 with SPAN-X (sperm protein associated with the nucleus mapped to the X chromosome). On two-dimensional Western blots of human sperm extracts, SPAN-X antibodies recognized 19 spots ranging from 20 to 23 kDa with isoelectric points from 5.0 to 5.5. Differential extraction of spermatozoa demonstrated that the SPAN-X protein is highly insoluble. Only 50% of ejaculated spermatozoa exhibited SPAN-X immunofluorescent staining. Dual localization of the sex chromosomes and the SPAN-X protein demonstrated that an equal number of X- and Y-bearing spermatozoa exhibited SPAN-X staining. In transfected mammalian CV1 cells, the SPAN-Xa and SPAN-Xb proteins were localized to the nucleus and cytoplasm, respectively, by indirect immunofluorescence. On immunoblots of CV1 cells, the SPAN-Xa protein migrated at 15-20 kDa, whereas the SPAN-Xb protein migrated at a higher molecular weight of 21-22 kDa. The SPAN-X protein was ultrastructurally associated with nuclear vacuoles and the redundant nuclear envelope. SPAN-X is the first protein specifically localized to these poorly characterized structures of the mammalian sperm nucleus and provides a unique biochemical marker for investigation of their function in spermatozoa as well as the role of SPAN-X/CTp11 in human tumors.

Amino Acid Sequence↗
PubMed1997

Improving care with nurse case managers: practical aspects of designing lipid clinics.

Compliance with the National Cholesterol Education Program (NCEP II) Adult Treatment Panel II guidelines for lipid management in patients with coronary artery disease has not been widespread. Barriers to effective lipid management occur at numerous levels of interaction between the patient, provider, and healthcare organizations. Nurse care managers (NCMs), recognized in the inpatient and discharge planning settings, are emerging in new roles in the outpatient setting working in subspecialty areas including lipid/risk-reduction, heart failure, and anticoagulation clinics. To improve patient adherence to NCEP II goals, NCMs can help overcome treatment barriers by: (1) bridging inpatient/outpatient care; (2) securing long-term patient compliance and follow-up; (3) developing clinic policy and computerized patient databases; (4) implementing management algorithms; and (5) enhancing financial reimbursement from insurers. Additional graduate nursing programs and novel healthcare delivery models demonstrating the ability to overcome the barriers to improved patient care must be encouraged and supported.

Ambulatory Care↗
PubMed1994

Human SP-10: acrosomal distribution, processing, and fate after the acrosome reaction.

SP-10 is a testis-specific acrosomal protein that has been detected in several species including humans. Extracts from whole human testis and epididymal, ejaculated, and capacitated sperm were analyzed by Western blot for SP-10 polypeptides. The testis extracts contained a full-length SP-10 protein at approximately 45 kDa as well as other immunoreactive SP-10 peptides at 32, 30, 28, and 26 kDa. Extracts from epididymal, ejaculated, and capacitated sperm contained several immunoreactive SP-10 peptides that co-migrated with the 32-26-kDa SP-10 peptides in the testis extracts. Epididymal, ejaculated, and capacitated sperm extracts did not contain the 45-kDa SP-10 peptide observed in testis extracts, but did contain immunoreactive SP-10 peptides from 25 to 18 kDa that were not detected in testis extracts. These results indicate that a full-length 45-kDa SP-10 precursor protein is present in the testis and that SP-10 peptides of 32, 30, 28, and 26 kDa result from proteolytic processing of the SP-10 precursor protein in the testis and/or alternative splicing. In addition, SP-10 peptides of 25-18 kDa were first detected in extracts of caput epididymal sperm and probably resulted from the proteolytic processing of the 45- and 32-26-kDa SP-10 peptides in the initial segment or caput epididymidis. Also, no additional SP-10 bands were detected in extracts of cauda epididymal, ejaculated, or capacitated sperm, suggesting that no further processing of the 32-18-kDa SP-10 peptides occurred during epididymal transit, ejaculation, and capacitation. Electron microscopic immunocytochemical observations of epididymal, ejaculated, and capacitated sperm revealed that colloidal gold labeling of SP-10 was most abundant within the principal segment and posterior bulb of the equatorial segment of the acrosome, while the colloidal gold labeling of SP-10 was sparse in the anterior equatorial segment of the acrosome. After a follicular fluid-induced acrosome reaction, SP-10 was detected on the inner acrosomal membrane in the equatorial segment and was associated with hybrid vesicles. This localization after the acrosome reaction is consistent with the hypothesis that SP-10 may be involved in sperm-zona binding or penetration.

Acrosome↗
PubMed1990

Oocyte retention after follicle luteinization.

Indirect evidence supports the existence of the luteinized unruptured follicle syndrome in infertile women. To seek direct evidence of oocyte retention, infertile and normal women were studied in the early and midluteal phase by visual documentation of ovulation stigma, needle aspiration of ovarian follicles, and peritoneal fluid collection for estradiol and progesterone assay. Luteal phase was confirmed by endometrial biopsy (postovulation day 2 to 8). In normal control subjects (n = 16), 25% of test cycles were stigma-negative and no oocytes were recovered. In infertile group (n = 23), 43% of test cycles were stigma-negative. Five oocytes were recovered including one from a stigma-bearing follicle. Peritoneal fluid steroid levels failed to discriminate stigma-positive from stigma-negative cycles in either group. Oocyte retention after luteinization occurs in infertile women.

Ascitic Fluid↗
PubMed1989

Concentration of acrosome stabilizing factor (ASF) in rabbit epididymal fluid and species specificity of anti-ASF antibodies.

Rabbit Acrosome Stabilizing Factor (ASF) concentrations were measured by immunoradiometric assay (IRA) in lumenal fluids obtained by micropuncture from the caput epididymidis, corpus epididymidis, cauda epididymidis, and the vas deferens of the rabbit. ASF was below the limit of detection in caput epididymidal fluids. Average ASF concentrations (3 bucks) in the corpus epididymidis, cauda epididymidis, and vas deferens were 880, 3363, and 3236 micrograms/ml, respectively. The average level of ASF in the cauda epididymidal fluid (CEF) represents from 10 to 23% of the total protein and is at least tenfold more than the amount previously determined to effect complete decapacitation of rabbit sperm by an in vivo assay. The average ASF concentration in seminal plasma from two vasectomized males was 0.155 micrograms/ml, approximately 100,000-fold less than is present in CEF and 2000-fold less than is present in normal seminal plasma. CEFs or seminal plasma from 11 different species were screened by Western blotting using high titer anti-ASF polyclonal antibodies to detect ASF-like molecules in other species. Only rabbit ASF was recognized.

Animals↗
PubMed1989

Sulfated oviductal glycoproteins in the rabbit: quantitation by competitive enzyme-linked immunosorbent assay.

The rabbit oviductal epithelium synthesizes and secretes a family of antigenically related, sulfated oviductal glycoproteins (SOG). Anti-SOG monoclonal antibodies (Mabs) were produced and two (Mab 1 and Mab 2) were selected for further characterization. Periodate oxidation of Western blots of oviductal fluid did not affect the binding of Mab 1 or Mab 2, thus suggesting that these antibodies recognized protein rather than carbohydrate epitopes on SOG. The specificity of Mab 1 was determined by Western blot analysis of tissues obtained from estrous rabbits and from the male rabbit reproductive tract. SOG was identified in tissue extracts of both the oviductal ampulla and isthmus. Cervix was the only non-oviductal tissue with which Mab 1 cross-reacted. Mab 1 was used to isolated SOG from whole oviductal fluid by immuno-affinity chromatography. Affinity-purified SOG and Mab 1 were used to develop a quantitative, SOG-specific, competitive enzyme-linked immunosorbent assay. This assay was used to quantify SOG in rabbit oviductal fluid collected during estrus and pseudopregnancy. SOG secretion during pseudopregnancy was resolved into two transient episodes of increased secretion. Maximum SOG secretion (X = 1039 +/- 199 micrograms/day) occurred within 48 h of the induction of pseudopregnancy. A second period of enhanced SOG secretion (X = 308 +/- 46 micrograms/day) occurred during the fifth and sixth days of pseudopregnancy. Baseline SOG secretion occurred during estrus at approximately 60% of maximum postovulatory secretion.

Animals↗
PubMed1989

Effect of steroid hormones on sulfated oviductal glycoprotein secretion by oviductal explants in vitro.

Explants of rabbit ampullary and isthmic tissue were cultured 4 days with and without exogenous steroids, and the sulfated oviductal glycoprotein (SOG) concentration in the explant culture supernatants was determined. Tissues cultured with progesterone plus estrogen secreted significantly more SOG than control tissues, whereas tissues cultured with estrogen alone did not. Ampullary tissues cultured with progesterone plus estrogen secreted significantly more SOG than control tissues on Days 2 and 3, whereas SOG secretion by isthmic tissues was significantly above control secretion on Day 4. Ampullary and isthmic tissues differed significantly in their secretory capacity. Maximum ampullary SOG secretion was approximately 650 ng SOG/mg tissue/day. Maximum isthmic SOG secretion was approximately 30 ng SOG/mg tissue/day. These findings suggest that the oviduct is composed of discrete functional regions that provide support to gametes and developing embryos through the unique secretory characteristics of each region.

Animals↗
PubMed1986

Chemical and physical characterization of rabbit sperm acrosome stabilizing factor.

Rabbit Acrosome Stabilizing Factor (ASF) is an epididymal product that reversibly inhibits the process of sperm capacitation. The native molecular weights of the monomer and dimer ASF were determined from sedimentation and diffusion data at 129,000 and 259,000 Mr. The monomer is composed of 92,000 and 38,000 Mr subunits according to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), with size heterogeneity demonstrated for the latter. The stoichiometry of the subunits appears to be one-to-one by gel scanning. Amino acid and carbohydrate compositions are characteristic of a globular glycoprotein, which is high in cysteine content and is 8.3% carbohydrate by weight. The sugar composition suggests the presence of both high mannose and complex N-linked oligosaccharides with the unusual feature of appreciable amounts of glucose. The isoelectric character of ASF spans a range from 5.3 to 7.0.

Amino Acids↗
PubMed1985

Sperm surface components involved in the control of the acrosome reaction.

Several lines of evidence suggest that decapacitation of sperm occurs normally in the male reproductive tract, and as a result the acrosome is stabilized and the acrosome reaction is controlled. Since the defining experiments in 1951, where decapacitation was reversed in the female reproductive tract by capacitation, investigations have pursued the molecular events of this process. This review attempts to examine critically the older literature and compare that perspective with the current theories. The theories for decapacitation of sperm include the possible role of a peptide decapacitation factor, a glycoprotein-mediated steroid transfer to the sperm, masking of a galactosyl transferase by some macromolecule-containing carbohydrate, preclusion of calcium influx by a binding protein, and sperm interaction with the acrosome stabilizing factor. Although these theories are diverse, there are some unifying aspects. However, there remain some major unanswered questions. For example, although we point to some circumstantial evidence that infers a single decapacitation factor, this needs to be further substantiated. It is concluded that with the purification of a macromolecule involved in capacitation, specific proposals on the mechanism of capacitation, and new tools to evaluate the capacitation process, it is likely that another decade will not pass without emergence of a unifying molecular theory of sperm capacitation.

Acrosome↗
PubMed1984

Evaluation of the site of synthesis of rabbit sperm acrosome stabilizing factor using immunocytochemical and metabolic labeling techniques.

Antibodies to rabbit acrosome stabilizing factor (ASF) were raised in mice and proved monospecific on Western electroblots . Anti-ASF was utilized to immunolabel tissue sections of male reproductive tract organs. Staining of principal cell cytoplasm was observed primarily in the corpus epididymidis (Regions 6 and 7), and secondarily in the cytoplasm of principal cells of the distal cauda epididymidis (Region 8b ) and the columnar cells of the vas deferens epithelium. The microvilli of principal cells in the proximal cauda epididymidis (Region 8a ) were densely stained. Spermatozoa appeared uniformly stained within the lumen of the corpus epididymidis and staining intensity increased distally. The Golgi region of corpus principal cells was not stained, nor were other cell types in this region. Testis, caput epididymidis, and accessory sex organs were not stained. Synthesis of ASF by corpus epididymidis was shown by immunoprecipitation of radiolabeled ASF from organ cultures of specific epididymal segments. Scant amounts of synthesis were also detected in the cauda epididymidis and vas deferens. The large subunit of ASF, immunoprecipitated from the corpus epididymidis, is 2000-4000 daltons larger than the large subunit of ASF from more distal regions of the reproductive tract, suggesting modification of this component.

Acrosome↗