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PubMedDate not supplied

Cervical cytology screening after tubal ligation.

Tubal ligation has become one of the most frequently performed surgical procedures, and estimates suggest that over 50 percent of all women will undergo surgical sterilization by age 45. Preventive health procedures such as Pap tests are often performed when women visit physicians for family planning and obstetric care. Since women do not visit physicians for these reasons following tubal ligation, it is important to know how their physician contact and Pap test coverage is affected by this surgery. We used data from the Manitoba Health Services Commission to construct health-services-use histories for the two years before and the two years after surgery for all women aged 25-44 who underwent tubal ligation in 1974 (n = 4,553) and for a comparison group of women who did not have the surgery (n = 5,161). Women visited physicians after surgery at the same rate as they had before surgery. However, the proportion of women receiving Pap tests fell in the years after surgery for the tubal ligation women but remained the same for the comparison group. The reasons for this decline in testing were a decline in the number of visits for gynecologic and obstetric reasons and a decline in testing because of high rates of "screening" prior to surgery. This study demonstrates both the importance of the one-time surgical event as an opportunity to offer Pap tests to women who might otherwise not visit physicians and the possibility of overtesting among some women.

Adult↗
PubMed1986

Phospholipid metabolism in bile duct-ligated rat plasma and erythrocytes.

Incorporation of [32P]orthophosphate into phosphatidylcholine, lysophosphatidylcholine and molecular species of phosphatidylcholine in vivo was observed in liver, plasma and erythrocytes of bile duct-ligated or sham-operated rats. Both the amount and radioactivity of dienoic species of phosphatidylcholine in all tissues examined increased in bile duct-ligated rats as compared to sham-operated rats. The experiments in vivo and in vitro showed that the ratio of lysophosphatidylcholine to phosphatidylcholine transferred to erythrocytes from plasma in sham-operated rats was much higher than that in bile duct-ligated rats. It is suggested that one of the mechanisms by which abnormal erythrocytes appear might be explained by the facilitated and direct transfer of phosphatidylcholine, which is caused by the interaction of erythrocytes with bile acid in bile duct-ligated rat plasma.

Animals↗
PubMed1986

Completion of excision repair in human cells. Relationship between ligation and nucleosome formation.

The completion of excision repair patches in human cells, following UV irradiation, was compared to the refolding of these regions into nucleosomes. Incomplete repair patches were detected by their enhanced sensitivity to exonuclease III. This enhanced sensitivity was due to the presence of gaps (or displaced parental strands) at the 3' end rather than unligated nicks, indicating that ligation occurs rapidly after repair synthesis is completed. Different rates of completion were achieved by treatment with the inhibitors hydroxyurea and sodium butyrate, as well as by using a (partially) ligase-deficient human cell strain. Hydroxyurea caused a marked decrease in both the rate of completion and the level of repair incorporation in all three cell types studied, while sodium butyrate yielded different effects in each cell type. In each case, however, a decrease in the rate of repair patch completion resulted in a concomitant decrease in the level of nucleosome formation. To determine the temporal relationship of these two events, the levels of repair-incorporated nucleotides in isolated 146-base pair nucleosome core DNA were compared on native and denaturing gels. The data indicate that little (or no) nucleosome formation occurred in the nascent DNA regions prior to ligation regardless of the cell type or treatment used. Furthermore, comparison of the fraction of unligated repair patches and the fraction of repair patches in a nonnucleosomal state indicated that in the absence of inhibitors there was a significant time lag between ligation and nucleosome formation. This lag time, however, decreased when cells were treated with hydroxyurea. Thus, the formation of nucleosomes in newly repaired regions of DNA occurred after the ligation step in all cases and these two features of the excision repair process are not "tightly coupled" events.

DNA↗
PubMed1979

Acid secretion in the bile duct-ligated pig.

Bile duct ligation is associated with severe gastric ulceration in the pig, but the pathogenesis is unknown. Gastric acid secretion was therefore studied before and after bile duct ligation in pigs with Heidenhain pouches. Basal pouch secretion and the response to submaximal pentagastrin stimulation incresed significantly 6--14 days after ligation of the common bile duct (P < 0,05). Bile duct ligation was not followed by gastric ulceration in the pigs in this study which had had, in effect, a 50--70% gastric resection in the course of fashioning the Heidenhain pouch. These observations suggest that oesophagogastric junction ulceration in pigs is associated with gastric acid hypersecretion.

Animals↗
PubMed1980

Kinetic intermediates in the formation of ordered complexes from cytochrome c fragments. Evidence that methionine ligation is a late event in the folding process.

The reactions of ferric heme-containing fragments with apofragments to form ordered complexes resembling native horse heart cytochrome c have been studied under conditions which resolve the overall process into consecutive second order and first order kinetic steps. In the initial, second order step the two fragments combine to form an intermediate complex which exhibits tryptophan 59 fluorescence quenching similar to native cytochrome c, but which has not yet achieved the native ligation state of the heme iron. The existence of first order processes following the second order step is demonstrated by absorbance changes in the Soret region. the entire absorbance change at 695 nm, relating to ligation of the sulfur atom of methionine 80 to the heme iron, is also associated with these first order processes. Thus, ligation of methionine is a late event in this self ordering of the polypeptide chains. Since the conformational energy is assumed to distinctly decrease in this late process of folding (Parr, G.R., and Taniuchi, H. (1980) J. Biol. Chem. 255, 2616-2623), it would follow that small spatial rearrangements of the polypeptide chains in the late stage of folding (as manifested by the ligation of methionine) are associated with a specific decrease in energy.

Animals↗
PubMed1983

Conventional versus laser reanastomosis of rabbit ligated uterine horns.

Conventional microsurgical reanastomosis was compared with laser microsurgical reanastomosis of the ligated uterine horn in the rabbit. Fourteen virgin female New Zealand white rabbits had both uterine horns ligated and divided at laparotomy. Four weeks later, seven rabbits had conventional microsurgical reanastomosis of the divided uterine horns after the ligated stumps were excised (group 1). The ligated uterine horns of the other seven animals were incised with a carbon dioxide laser with a power density of 637 to 796 W/cm2 followed by conventional microsurgical reanastomosis using polyglactin (Vicryl) 8-0 sutures (group 2). After six weeks, a laparotomy was performed to determine adhesion formation and uterine horn patency by chromopertubation. Adhesion formation was graded 0 (no adhesions) through 3 (extensive, dense adhesions) for each uterine horn. Only one uterine horn in the control group was not patent. Laser microsurgery produced significantly less adhesion (mean +/- SE, 0.79 +/- 0.24) than conventional microsurgery (2.29 +/- 0.13) (P less than .001). The findings indicate that laser microsurgical tubal reanastomosis produces significantly better results with less adhesion than the conventional microsurgical technique.

Animals↗
PubMed1981

Differences in experimental pancreatic carcinogenesis induced by oral or subcutaneous administration of 2,2'-dihydroxydi-n-propylnitrosamine in duct-ligated hamsters.

After ligation of the main pancreatic duct in the splenic lobe, Syrian golden hamsters were treated, either p.o. or s.c., for 15 weeks with dihydroxydi-n-propylnitrosamine for induction of pancreatic duct carcinomas. The incidence, location, and type of proliferative lesions distal and proximal to the ligature were recorded and compared to those of dihydroxydi-n-propylnitrosamine-treated hamsters without duct ligation. Proliferative duct lesions, including carcinomas, developed on either side of the ligation. While after s.c. administration the incidence was similar to that in nonligated animals, a markedly decreased incidence was found in p.o.-treated animals with duct ligation. The data suggest that the blood stream might be one major access route of the carcinogen to the pancreatic duct cell. Furthermore, it is assumed that an umimpaired release of pancreatic juice in the duodenum is necessary for the enteral resorption of dihydroxydi-n-propylnitrosamine.

Adenocarcinoma↗
PubMed1994

Maturation of acute T-lymphoblastic leukemia cells after CD2 ligation and subsequent treatment with interleukin-2.

In this study, we have investigated the ability of various cytokines to induce the maturation of acute lymphoblastic leukemia (T-ALL) cells with early T-cell phenotype. Leukemic blasts from 17 untreated T-ALL patients were assayed for their ability to acquire mature T-cell markers, CD3/T-cell receptor (TCR) in particular, after incubation with one or a combination of recombinant human interleukin-1 (IL-1), IL-2, IL-4, IL-7, and CD2-specific monoclonal antibody (MoAb). IL-7 or IL-2 induced the proliferation of some leukemic cells, whereas sequential cell treatment with CD2-MoAb and then IL-2 promoted CD3/TCR expression on nearly all CD2+ cells (15 of 16), except for 1 T-ALL that developed into CD3-CD16+CD56+ cells. Differentiation of T-ALL cells was also evidenced through the downregulation of CD34 precursor cell antigen, the generation of CD4+ and CD8+ cells from CD4+ CD8+ precursors, and the acquisition of mature T-cell functions. CD2 ligation induced a progressive increase of surface expression of IL-2 receptor alpha (IL-2R alpha) and IL-2R beta and an accelerated in vitro death of leukemic cells. The ligation of IL-2R by IL-2 rescued T-ALL cells from death and promoted their progression toward more mature cells expressing extracellular CD3/TCR alpha beta complexes. Intracellular analysis indicates that TCR alpha transcription and membrane translocation of both TCR alpha and TCR beta were promoted in these conditions. Analysis of intracellular signals transduced during T-ALL differentiation indicated that CD2-ligation induced Ca2+ influx and that the ligation of CD2 and IL-2R induced distinct tyrosine phosphorylation patterns. The addition of inhibitors of tyrosine phosphorylation abolished T-ALL cell differentiation, which suggests the involvement of tyrosine kinases in this phenomenon. Together, we showed the constant maturation of leukemic early T cells after stimulation of surface CD2 and the high-affinity IL-2R.

Antibodies, Monoclonal↗
PubMed1994

An in vitro ligation and transfection system for inserting DNA sequences into the latency-associated transcripts (LATs) gene of herpes simplex virus type 1.

This report describes a simple, rapid and highly efficient method for introducing specific DNA sequences into a defined locus of the herpes simplex virus type 1 (HSV-1) genome by restriction enzyme cleavage and ligation. The genome of the HSV-1 strain HFEM contains a 4.1 kb deletion in one copy of the RL region, deleting one copy of the latency-associated transcript (LAT) gene. It does not contain any site for restriction enzyme PacI. Two unique PacI restriction enzyme sites flanking an HSV-1 ICP6 promoter-LacZ reporter gene cassette were engineered into the LAT region to generate a recombinant virus HFEM/ICP6-LacZ which produced blue plaques in the presence of X-gal. This viral vector allowed the insertion of foreign genes directly into the HSV-1 genome by restriction enzyme digestion and ligation. The system was tested by digesting the HFEM/ICP6-LacZ DNA with PacI and with SwaI (an endogenous unique restriction enzyme site upstream of the LAT promoter locus and inserting by in vitro ligation a LAT promoter-LacZ gene cassette into the HFEM/ICP6-LacZ genome. The new recombinant virus HFEM/LAT-LacZ was detected as white plaques in the presence of X-gal, since beta-galactosidase expression, when driven by the LAT promoter, is not detectable during viral replication in tissue culture. The high yield (approximately 100%) of the recombinant virus obtainable from this in vitro ligation and transfection procedure coupled with a blue-white or reversible white-blue plaque detection scheme makes this a powerful method for constructing HSV-1 vectors around the LAT promoter locus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Distinct signal transduction in mouse CD4+ and CD8+ splenic T cells after CD28 receptor ligation.

Current evidence suggests that recognition of Ag/MHC by the TCR alone is insufficient to lead to T cell proliferation or effector function. For a Th cell to produce sufficient IL-2 to allow autocrine-driven clonal expansion, there is a requirement for so-called "costimulatory" or "accessory" signals in addition to TCR ligation by Ag/MHC. Although the first signal delivered by TCR ligation has been well characterized, information regarding the biochemical nature of second signals is limited. In the present report, using a newly generated mAb specific for CD28, signal transduction by the CD28 receptor has been studied in mouse splenic T cells. When freshly isolated splenic T cells were assessed, cross-linking of CD28 by mAb did not induce increases in intracellular calcium concentration were assessed, cross-linking of CD28 by mAb did not induce increases in intracellular calcium concentration whereas TCR cross-linking was able to induce calcium mobilization. In contrast, when T cells were activated by phorbol ester treatment or by in vitro culture, CD28 ligation was able to induce calcium mobilization in 60 to 70% of splenic T cells. Unexpectedly, the CD28-induced calcium response was mainly limited to T cells of the CD4+ subset, whereas both CD4+ and CD8+ T cell subsets showed increases in [Ca2+]i of similar magnitude after CD3 epsilon ligation. The temporal nature of the CD28-induced signal was also different from TCR-induced calcium mobilization. CD28-induced signals were delayed in onset and sustained in duration in contrast to TCR signals that had short latency and brief duration. Differential expression of CD28 on the surface of activated CD4+ or CD8+ T cells did not appear to account for the differences in signal transduction between the two T cell subsets. The preferential responsiveness of the CD4+ T cell population to CD28-induced signaling was also observed in downstream events such as the induction of IL-2R, CD69 expression, and in cellular proliferation. These results indicate that the costimulatory signal delivered by CD28 may have fundamentally different biochemical properties in CD4 and CD8 T cell subsets, and therefore the functional role of CD28 may differ in these T cell subsets.

Animals↗
PubMed1995

[Clinical experience with modified method of tubal ligation].

OBJECTIVE: To evaluate the clinical results with modified tubal ligation method. METHODS: From 1983 to 1992, 700 cases of modified tubal ligation operation with tubes cut and overlapped were performed in our hospital, and this was compared with 602 cases of Pomeroy's and 502 cases of modified Uchida's method. Patients were followed at 6 months, 2 and 5 years. Pregnancy rates, menstruation disturbances, lower abdominal or back pain, and leucorrhea were observed. RESULTS: Patients with modified tubal ligation method had a pregnancy rate of 0.43%, which was significantly lower than that of Pomeroy's 1.50% (P < 0.05). The modified method group also had few complications. The occurence rate of menorrhage and prolonged bleeding were apparently lower than that of Pomeroy's too (P < 0.01). CONCLUSION: This modified tubal ligation method is more effective and practicable than Pomeroy's and modified Uchida's method.

Adult↗
PubMed1997

MHC class I ligation of human T cells activates the ZAP70 and p56lck tyrosine kinases, leads to an alternative phenotype of the TCR/CD3 zeta-chain, and induces apoptosis.

Cross-linking of MHC class I (MHC-I) molecules on human T cells induces signal-transduction events, including activation of tyrosine kinases, tyrosine phosphorylation of phospholipase C-gamma 1, and elevation of the intracellular free calcium concentration. In this study, we demonstrate that the ZAP70 tyrosine kinase is tyrosine phosphorylated in Jurkat T cells and in purified peripheral T cells after MHC-I ligation. The tyrosine-phosphorylated ZAP70 kinase exhibits a particular phenotype with low affinities for proteins at 21, 40, 60, and 120 kDa, proteins normally co-precipitated with ZAP70 after TCR/CD3 stimulation. The phosphorylation of ZAP70 after MHC-I ligation was dependent on TCR/CD3 surface expression. One of the natural substrates for ZAP70 is the zeta-chain dimer of the TCR/CD3 complex. MHC-I cross-linking induces a phosphorylated zeta-protein that migrates as a dimer at 42 kDa in SDS-PAGE and differs from the 38-kDa phosphorylated zeta-protein dimer induced by TCR/CD3 cross-linking. Furthermore, we demonstrate that the p56lck tyrosine kinase is tyrosine phosphorylated following MHC-I ligation, and that a p56lck-negative Jurkat T cell mutant does not induce phosphorylation of the zeta-chain and the ZAP70 kinase following MHC-I ligation. Previous studies have demonstrated that lack or diminished activation of ZAP70 is involved in the induction of anergy or apoptosis in T cells. Likewise, MHC-I cross-linking of Jurkat T cells results in growth arrest and induction of apoptosis that is strongly inhibited by herbimycin A, suggesting an essential role of tyrosine kinase activity in the process leading to apoptosis.

Antibodies, Monoclonal↗
PubMed1998

Ligation of cell surface CD38 protein with agonistic monoclonal antibody induces a cell growth signal in myeloid leukemia cells.

CD38 is expressed during early stages of differentiation in normal and leukemic myeloid cells. Recently, CD38 has been shown to participate in intracellular signal transduction pathways following its ligation with CD38-specific mAbs. In this study we report that ligation of CD38 by one such agonistic mAb (IB4) induced proliferation of cultured leukemic cells in vitro. In HL-60, KG-1A, NB4, and OCI-AML-3 myeloid leukemia cell lines, IB4 mAb induced an increase in the proliferating cell fraction as determined by cell number, clonogenic assay, and flow cytometric analysis. The presence of Ab caused a dose-dependent increase in the number of CFU and an increase in cell divisions. HL-60-Dox cells (a HL-60-doxorubicin-resistant cell line), which have no detectable CD38 expression, failed to respond to IB4 mAb. The effect of CD38 ligation on cell growth was also evaluated in freshly isolated leukemic cells from patients with acute myelogenous leukemia (AML). A significant increase in the proliferating cell fraction (S+G2M) was observed in 50% of the patients incubated with IB4 mAb. In five of the six AML patients, anti-CD38 mAb stimulated the proliferation of AML colony-forming cells. These results suggest that ligation of CD38 can induce the proliferation of leukemic cells and may play a role in the propagation of leukemic cell clones in certain cohorts of AML patients.

ADP-ribosyl Cyclase↗
PubMed1976

The effects of ligation of vas deferens, corpus epididymidis and vasa efferentia on the testicular function in rats.

The effects of ligation of the vas deferens, the corpus epididymidis and the vasa efferentia on the testicular function were studied in sexually mature rats. The significant decrease in the testicular weight was observed after ligation of the corpus epididymidis and the vasa efferentia. However, neither the weight of the ventral prostate and of the seminal vesicle, nor the plasma testosterone level showed significant changes. The results suggest that the ligation at the three locations would not affect the endocrine function of the testis. The changes in the testis would mainly affect the spermatogenesis. The effects of sperm stasis on the testicular function were also discussed.

Animals↗
PubMed1980

Follow-up on maxillary artery ligation for epistaxis.

Forty-six transantral maxillary artery ligation cases were compared with 30 controls with regard to the outcome of their treatment of epistaxis. The success rate and the complication rate were higher in the ligated patients. Maxillary artery ligation for severe idiopathic epistaxis is a valid procedure only if injury to the infraorbital nerve is avoided.

Epistaxis↗
PubMed1996

Chronic aspiration in children. When are bilateral submandibular gland excision and parotid duct ligation indicated?

OBJECTIVE: To assess the efficacy of bilateral submandibular gland excision and bilateral parotid duct ligation in treatment of chronic aspiration in neurologically impaired children. DESIGN: Retrospective chart review and telephone follow-up interview. SETTING: Tertiary care center. PATIENTS: All patients from 1986 through 1994 who underwent bilateral submandibular gland excision and bilateral parotid duct ligation and had evidence of at least 1 episode of aspiration pneumonia in the year prior to undergoing surgery. MAIN OUTCOME MEASURE: Two main outcomes measures were (1) the change in number of hospitalizations for pneumonia and total number of lower respiratory tract infections between 1 year before and 1 year after surgical intervention and (2) telephone assessment of patient outcome with respect to parental satisfaction, effect on quality of life, care requirements, amount of suctioning, and use of voice. RESULTS: Sixteen patients aged 16 months to 18 years were included. After surgical intervention, there was a significant decrease in the mean (+/-SD) number of pneumonias (2.3 +/- 1.44 before surgery, 0.9 +/- 1.2 after surgery; P < .001) and hospitalizations (1.2 +/- 0.8 before surgery, 0.4 +/- 0.8 after surgery; P < .005). Six patients had a tracheostomy at the time of surgery, and 1 required a tracheostomy 2 years after surgery. No individual required laryngotracheal separation. Eleven families were able to be contacted by telephone. Caretakers reported that in 8 of 11 patients, quality of life was improved and care requirements decreased. Seven patients used voice for at least some degree of communication. Three patients had postoperative complications involving the parotid glands; all resolved after further therapy. CONCLUSION: Bilateral submandibular gland excision and bilateral parotid duct ligation reduce the incidence of aspiration pneumonias and hospitalization, and decrease overall care requirements in a select group of neurologically impaired children. Because they are voice sparing, are efficacious, and have a low morbidity, they should be considered before laryngotracheal separation or tracheoesophageal diversion.

Adolescent↗
PubMed1993

Radial or ulnar artery laceration. Repair or ligate?

OBJECTIVE: To determine the relationship between patency of radial or ulnar artery repair and later hand symptoms. DESIGN: Call-back survey. SETTING: Urban trauma center. PATIENTS: Thirty-two subjects with wrist artery lacerations undergoing 26 arterial repairs and six artery ligations during an 8-year period. INTERVENTIONS: Directed history and hand examination (palpation of wrist pulses, Doppler Allen test, and Doppler interrogation of palmar arch and digital vessels). MAIN OUTCOME MEASURES: History of hand claudication, weakness, or cold sensitivity or paresthesias and patency of wrist arteries. RESULTS: Twelve (46%) of 26 wrist artery repairs were patent. There was no evident benefit of optical magnification or specialization in hand or vascular surgery. No subjects had hand claudication; there was a 50% incidence of hand weakness and a 12% incidence of cold sensitivity independent of patency of the damaged wrist artery and present only in subjects with associated nerve injury. Professional charges for wrist artery repair were threefold to fourfold higher than those for wrist artery ligation. CONCLUSION: Consonant with prior reports, patency following repair of radial or ulnar artery laceration does not exceed 50%. Later hand symptoms relate to nerve or tendon damage, not to arterial patency. In the absence of acute hand ischemia, simple ligation of a lacerated radial or ulnar artery is safe and cost-effective.

Adolescent↗
PubMed1975

Hepatic artery ligation and postoperative chemotherapy for hepatic metastases: clinical and pathophysiological results.

Nineteen patients underwent hepatic artery ligation for metastatic cancer of the liver. Metastases were from colon cancer in 13 and from other primary cancers in 6. Postoperative chemotherapy was given to 15 by the systemic route, and to 1 by infusion into the ligated hepatic artery. Sixteen patients survived the procedure. In these patients, the mean survival of those with metastases from colon cancer was 27+ (5-72) weeks, and from other cancer 50+ (8-23) weeks. Among the patients evaluated, 57% had symptomatic improvement, 43% showed improvement in the liver scan, and 33% had a decrease in liver size. Our experience suggests that hepatic artery ligation can offer temporary but significant palliation in carefully selected patients.

Adult↗