Purification of DNA fragments from lyophilized agarose gels.
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DNA↗
Biomedical subjects
L Anderson
Publications and source records attributed to L Anderson.
Rapid desensitization of the thyrotropin-releasing hormone receptor expressed in single human embryonal kidney 293 cells.
This study uses fluorescence microscopy combined with dynamic video imaging to examine the events associated with the rapid desensitization of the thyrotropin-releasing hormone receptor (TRH-R). In single non-pituitary human embryonic kidney 293 (HEK-293) cells, expressing either the rat or human TRH-Rs, TRH produced a rapid dose-dependent monophasic rise in [Ca2+]i. This Ca2+ transient was completely abolished by pretreatment of cells with the intracellular Ca2+ antagonists thapsigargin or cyclopiazonic acid, but not EGTA, the voltage-operated Ca2+ channel (VOCC) antagonist nifedipine or the second-messenger-operated Ca2+ channel antagonist SK&F 96365. These results suggest that TRH causes the mobilization of Ca2+ from thapsigargin/cyclopiazonic acid-sensitive intracellular Ca2+ stores but not the influx of extracellular Ca2+. HEK-293 cells also failed to respond to KCl or the slow Ca(2+)-channel activator BAY K 8644, suggesting that they lack L-type VOCCs. Rat and human TRH-Rs are highly conserved except at the C-terminus where the sequence differs. The C-terminus is believed to be important in receptor desensitization. Despite differences in this region, rat and human TRH-Rs expressed in HEK-293 cells underwent rapid (within 1 min) desensitization. This desensitization was dose-dependent and did not involve receptor loss. Similarly the bradykinin receptor endogenous to HEK-293 cells also displays a rapid desensitization. We conclude that in TRH-R-expressing non-pituitary HEK-293 cells, TRH mobilizes intracellular Ca2+ resulting in a monophasic Ca2+ transient. The rat and human TRH-Rs as well as the endogenous bradykinin receptor also displayed rapid receptor desensitization.
Animals↗
A familial Alzheimer's disease locus on chromosome 1.
The Volga German kindreds are a group of seven related families with autosomal dominant early-onset Alzheimer's disease (AD). Linkage to known AD-related loci on chromosomes 21 and 14 has been excluded. Significant evidence for linkage to AD in these families was obtained with D1S479 and there was also positive evidence for linkage with other markers in the region. A 112-base pair allele of D1S479 co-segregated with the disease in five of seven families, which is consistent with a common genetic founder. This study demonstrates the presence of an AD locus on chromosome 1q31-42.
Adult↗
The relationship between the technical accuracy of stereotactic interstitial implantation for high grade gliomas and the pattern of tumor recurrence.
PURPOSE: To correlate the pattern of failure and subsequent survival with the technical accuracy of stereotactic brain tumor implantation. METHODS AND MATERIALS: The patterns of failure of 47 consecutive patients with primary or recurrent gliomas after stereotactic implantation delivering 60 Gy via removable high activity 125I sources were reviewed. When the tumor was covered at all levels by the chosen isodose distribution, the implant was considered to be "ideal." If the coverage was not complete, a numerical description of the volume of tumor outside the isodose was assigned. Criteria for "adequate" and "inadequate" implants were defined. Standard radiographic criteria, with pathologic confirmation in 26 cases, were used to categorize the patterns of failure into the following components: central, peripheral, distant (within the brain parenchyma), leptomeningeal, and spinal. A peripheral failure was scored as being in the "direction of error" when the prescribed isodose did not cover the tumor volume and the subsequent tumor progression was in this region. Survival was calculated from the date of implantation. RESULTS: Of 47 cases examined, 72% had an element of central and/or peripheral failure and 23% had a component of distant or meningeal failure. Among the patients with "adequate" or "inadequate" ("nonideal") implants who had a component of peripheral failure, only 19% were in the "direction of error." All patients with technically "inadequate" implants progressed in both the central and peripheral region. Among the groups who had "ideal," "adequate," and "inadequate" implants; 37%, 70%, and 75%, respectively, underwent reoperation [p = not significant (NS)]. Patients who underwent reoperation had a longer median survival than those who did not; 521 days vs. 298 days, respectively (p = 0.035). For patients with "nonideal" implants, a median survival of 470 days was found for patients undergoing reoperation vs. 184 days for those who did not (p = 0.016). CONCLUSIONS: (a) Patients with "inadequate" implants failed in both the central and peripheral region in all cases. This pattern, while less common in those with "ideal" or "adequate" implants, occurred in the majority of cases. (b) The technical excellence of the implant had no impact on survival. (c) Patients with "nonideal" implants were more likely to have reoperation than those with "ideal" implants, and this intervention was associated with a significant survival advantage.
Adult↗
COMMIT anti-smoking program shows modest success.
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Humans↗
Fiber intake of normal weight, moderately obese and severely obese subjects.
The lack of dietary fiber may be a contributing factor in obesity. This study examined the fiber intake of three weight groups: normal (20.0 < or = BMI < or = 27.0), moderately obese (27.1 < or = BMI < or = 39.9) and severely obese (BMI > or = 40.0). Each group contained 50 subjects. Detailed 3-day food records were used to gather the nutritional data. Fiber intake in the normal weight group was 18.8 +/- 9.3 grams, the moderately obese consumed 13.3 +/- 5.8 grams of fiber and the severely obese 13.7 +/- 5.7 grams. Total fiber intake in grams was found to be significantly higher in the lean group (p < 0.05) and was positively associated with sex and education level with men and more highly educated individuals consuming more fiber. Using regression analysis total fiber in grams and fiber in g/1000 kcalories was inversely associated with BMI after adjusting for sex, age, education level and income (p < 0.01). A high fiber diet may help to promote a negative energy balance by causing early satiety secondary to gastric distention. Dietitians and physicians need to emphasize the importance of a high fiber diet to their obese patients.
Adult↗
Effects of oltipraz and related chemoprevention compounds on gene expression in rat liver.
One promising approach to cancer chemoprevention involves the induction of phase II xenobiotic metabolism enzymes. Since this approach requires drugs specifically intended to alter tissue gene expression patterns over long periods, it will be important to determine experimentally which proteins are increased or decreased by treatment, and how such alterations may (or may not) be related to the postulated chemopreventive mechanism. We have employed two-dimensional electrophoresis to detect and quantitate gene expression effects of candidate chemoprevention compounds in the livers of treated rats. Oltipraz, an inducer of several phase II enzymes, affected a series of at least 26 proteins, most of which were slightly decreased by treatment. Several proteins were increased, the prime example being rat liver spot 693, which was induced more than 7-fold by oltipraz. This protein was excised from multiple 2-D gels and subjected to in situ tryptic digestion followed by microchemical sequence analysis. The resulting multiple peptide sequences match perfectly with the cDNA-derived sequence of rat aflatoxin B1 aldehyde reductase (AFAR). Using quantitative measurements of AFAR from 2-D gels, we compared a series of dose regimens. Oltipraz administration by gavage or in diet appeared equally effective, while recovery studies indicated a half-time of 5.5 days for disappearance of the AFAR protein.(ABSTRACT TRUNCATED AT 250 WORDS)
Amino Acid Sequence↗
Characterization of novel phorbol ester- and serum-responsive sequences of the rat ornithine decarboxylase gene promoter.
Ornithine decarboxylase (ODC), the key regulatory enzyme in mammalian polyamine biosynthesis, is rapidly induced by mitogens and tumor promoters. We used transient expression assays and DNA-protein binding studies to examine the regulation of ODC promoter activity by phorbol esters and serum growth factors. A fragment of the ODC 5' flanking region (nt-1156 to +13) was sufficient to confer 12-O-tetradecanoylphorbol-13-acetate (TPA)-responsive expression to a luciferase reporter gene when transfected into H35 cells. However, induction by TPA was not observed in Rat2 fibroblasts, although refeeding of serum-starved Rat2 cells with fresh serum-containing medium rapidly induced a fivefold to sixfold increase in ODC promoter activity, maximal about 8 h after refeeding. Deletion analysis demonstrated that several sequences contributed to basal ODC promoter activity but that nt -92 to +13 was sufficient for induction by TPA or by serum. This sequence lacked canonical TPA-responsive elements, and an activator protein-1 (AP-1) consensus oligonucleotide failed to compete effectively for proteins binding to this region. Two of four protein complexes observed by gel-shift analysis of nt -92 to +13 were competitively inhibited by wild-type but not mutant oligonucleotides encompassing a variant cyclic AMP-response element (CRE) (ODC nt -50 to -42); however, a consensus CRE did not compete. Mutagenesis of this site demonstrated that it contributes to basal expression of the ODC promoter but not to TPA or serum responsiveness. Thus, we conclude that the proximal ODC promoter (nt -92 to +13) responds to TPA and serum stimulation in a cell-type-specific manner that is not mediated by canonical AP-1 elements.
Animals↗
Tensile fatigue of 4-META cement bonding three base metal alloys to enamel and comparison to other resin cements.
The tensile median fatigue limits and fracture mode of 4-META cement were evaluated after bonding Ni-Cr, Ni-Cr-Be, and Co-Cr alloys to enamel. Alloy surfaces, 6 mm in diameter, were grit blasted with 50 microns Al2O3 and cemented to etched bovine enamel under a 2 kg load. Samples were cycled in tension to failure or 10(6) cycles at 5 Hz in Ringer's solution at 37 degrees C. Two-point strategy was used to determine median fatigue limits (S50). Fracture modes were evaluated by SEM on samples failing before 10(6) cycles. Results indicated differences between all sample groups where S50 (Ni-Cr-Be) > S50 (Co-Cr) > S50 (Ni-Cr). Failure analysis revealed mixed cohesive fractures near both interfaces with small areas of delamination within the cement. Comparison to reported median fatigue limits of two commercially available cements were discussed.
Acrylic Resins↗
Liver resection for colorectal liver metastases.
The management of patients with colorectal liver metastases is still controversial. Recent evidence suggests benefit for resection of localized metastases within a single lobe of the liver. A series of 49 patients undergoing liver resection for localized liver metastases is presented. Resection involved right hepatectomy (23), left hepatectomy (8) and segmental excision (18). The median age was 62 (range 40-77). Patients have been followed for a period of up to seven years. The overall median survival was 24 months. The actuarial 3-year survival was 57.9%. There was no significant correlation of survival with the degree of differentiation or Dukes staging of the primary tumour. This series adds further weight to the evidence supporting resection in selected patients with colorectal liver metastases.
Adult↗
Mixed-lineage acute myeloid leukemia associated with a suprasellar dysgerminoma.
An association between primary mediastinal germ cell tumors and hematologic malignancies has been recognized since 1985. We present a patient with a suprasellar germ cell tumor and an associated leukemia. A 20-year-old black female presented in December 1987 with a 6-month history of headaches and weight loss, confusion, polyuria, and polydipsia. Evaluation revealed hypernatremia, normal neurologic examination except poor recall, and an enhancing inhomogeneous suprasellar mass on cranial computed tomography. Biopsy of the mass diagnosed a dysgerminoma, which was treated with craniospinal radiation. In February 1988, the patient developed pancytopenia, which resolved with discontinuation of cimetidine and phenytoin. She did well until June 1988 when she presented with skin lesions over the trunk and extremities. Skin biopsy revealed a leukemic infiltration. She was admitted with a WBC 1,500/microliter (without blasts), Hb 11.6 g/dl, PLT 210,000 microliter. Bone marrow biopsy revealed hypercellularity with 50% blasts, demonstrating mixed-lineage acute myeloblastic leukemia (myelomonocytic-M4; megakaryoblastic-M7). The patient was induced with a standard Ara-C/daunorubicin regimen. Two weeks postinduction, she became septic and expired. An autopsy demonstrated leukemic involvement of the spleen, liver, bone marrow, and skin, without residual dysgerminoma. This represents the first reported case of suprasellar dysgerminoma associated with a mixed-lineage leukemia not related to chemotherapy.
Adult↗
Joint CNS appointment: is it viable?
A CNS joint appointment that is supported by the departments of nursing and medicine is viable when goals of the nurse and the organizations are congruent and expectations are delineated. Many challenges and strategies are associated with a joint appointment. Although the challenges and strategies were similar for the first (C.N.) and second authors (L.A.), their experiences differed. Based on the experience of the authors, feasibility of a joint appointment and benefits, challenges, and strategies for enacting the role are presented.
Feasibility Studies↗
Rapid desensitization of GnRH-stimulated intracellular signalling events in alpha T3-1 and HEK-293 cells expressing the GnRH receptor.
The gonadotropin-releasing hormone receptor (GnRH-R) desensitizes following chronic exposure to GnRH or its agonists. However, it is not certain whether the GnRH-R undergoes rapid homologous desensitization analogous to other members of the G-protein coupled receptor (GPCR) superfamily. This study investigated rapid desensitization events in two cell lines expressing the GnRH-R; (the pituitary gonadotrope alpha T3-1 cell line and the stably transfected human embryonal kidney cells, HEK-293). In both cell types, total inositol phosphate (IP) production did not desensitize, increasing linearly over 10 min. Short-term GnRH pretreatment also did not desensitize the rapid phase ( < or = sec) of the early Ins1,4,5P3 response despite a partial desensitization of the plateau phase ( > 1 min). It is likely that Ins1,4,5P3 metabolism rather than desensitization is responsible for this partial effect. In contrast, GnRH-stimulated calcium responses did desensitize in a dose-dependent fashion in both alpha T3-1 and HEK 293 cells expressing the GnRH-R. These results suggest that rapid GnRH-R desensitization occurs at a level beyond both the receptor and phospholipase C (PLC) activation. These events were receptor specific and not related to cell type, since similar rapid desensitization profiles were observed in both GnRH-R expressing pituitary and nonpituitary cell types. In contrast, profiles of GnRH-stimulated calcium responses were cell type specific.
Animals↗
Reading-induced absence seizures.
Reading epilepsy usually presents with jaw myoclonus and generalized tonic-clonic seizures. We report a 12-year-old girl with absence seizures induced by reading, which were diagnosed by video EEG. An absence seizure with generalized 3-Hz spike-and-wave discharge occurred within 30 seconds of each reading session. Treatment with valproate caused complete seizure control, with therapy successfully discontinued after 2 years.
Child↗
HIV seroprevalence and risk behaviors among lesbians and bisexual women in San Francisco and Berkeley, California.
Few data are available on human immunodeficiency virus (HIV) infection and risk behaviors among lesbians and bisexual women. A total of 498 lesbians and bisexual women was sampled from public venues in San Francisco and Berkeley, Calif, during 1993. The overall HIV seroprevalence was 1.2%. Ten percent of participants reported injecting drugs since 1978. Forty percent of the participants reported unprotected vaginal or anal sex with men during the past 3 years, including unprotected sex with gay and bisexual men and male injection drug users. The high rates of injection drug use and unsafe sexual behaviors suggest that lesbians and bisexual women frequenting public venues in San Francisco and Berkeley are at risk for HIV infection.
Adolescent↗
Linkage of early-onset osteoarthritis and chondrocalcinosis to human chromosome 8q.
Calcium pyrophosphate-deposition disease (CPDD), also called "chondrocalcinosis" or "pseudogout," is a disorder characterized by the deposition of calcium-containing crystals in joint tissue, which leads to arthritis-like symptoms. The presence of these crystals in joint tissue is a common finding in the elderly, and, in this population, there is a poor correlation with joint pain. In contrast, early-onset CPDD has been described in several large families in which the disease progresses to severe degenerative osteoarthritis (OA). In these families, an autosomal dominant mode of inheritance is observed, with an age at onset between the 2d and 5th decades of life. In this report, we describe a large New England family with early-onset CPDD and severe degenerative OA. We found genetic linkage between the disease in this family and chromosome 8q, with a multipoint lod score of 4.06. These results suggest that a defective gene at this location causes the disease in this family.
Adult↗
Quantitative DNA analysis: a comparison of conventional DNA ploidy analysis and teleploidy.
JPEG compression can be used on images for DNA ploidy analysis if careful consideration is given to the level of compression used for file storage. The amount of JPEG compression possible may vary depending on the type of tissue analyzed, however, a compromise may be reached for all types of tissue. JPEG compression should not go over a level of 70 for DNA analysis as this would result in possibly erroneous IOD calculation and erroneous DNA ploidy analysis. Also, the resulting file quality is so poor that even visual analysis is not possible. With careful training of personnel in cell selection, remote DNA ploidy analysis would be an effective tool for standardization and quality control in the pathology laboratory. By using remote DNA ploidy analysis, it is possible for hospitals to consolidate their workload, and make DNA ploidy analysis by image cytometry a cost effective test in the laboratory. Proficiency testing would also become possible as all laboratories performing DNA ploidy analysis would receive the same fields of view for testing. DNA ploidy analysis by image cytometry using stored images could be a versatile tool for the telepathology community.
Animals↗
The effectiveness of the Masterson curette in sampling the endometrial cavity.
The Masterson curette was used to sample the endometrial cavity of 25 women prior to scheduled hysterectomy for benign or malignant pathology. Adequate amount of tissue was obtained in 20 (87%) of 23 patients who did not have endometrial atrophy. The Masterson curettage detected all seven cases of endometrial hyperplasia or adenocarcinoma for a sensitivity of 100%. However, the Masterson curette does not sample the entire endometrial cavity. If abnormal uterine bleeding persists despite normal histology on curettings obtained with the Masterson or other endometrial sampling device, hysteroscopy is recommended.
Adenocarcinoma↗