Coherent squeezed states of motion in an ion trap generated with Raman-driven sideband transitions.
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Journal Article↗
Biomedical subjects
F Lin
Publications and source records attributed to F Lin.
Detection of the BCR-ABL gene by reverse transcription/polymerase chain reaction and fluorescence in situ hybridization in a patient with Philadelphia chromosome negative acute lymphoblastic leukaemia.
The Philadelphia (Ph) chromosome is detected in leukaemia cells in approximately 20% of adults with acute lymphoblastic leukaemia (ALL). When treated with chemotherapy alone, Ph-positive ALL has a poor prognosis, and patients may benefit from bone marrow transplantation in first remission. Here we report a patient with chromosomally normal bone marrow, in all 60 cells analysed, who was found to have the p210-type BCR-ABL chimaeric transcript by RT/PCR. Fluorescence in situ hybridization was labelled cosmid probes for BCR and ABL showed the presence of BCR-ABL juxtaposition on a normal chromosome 22 in leukaemia cell metaphases. We conclude that molecular and cytogenetic methods should be used in conjunction to detect the BCR-ABL gene rearrangement in ALL.
Adult↗
Variable numbers of BCR-ABL transcripts persist in CML patients who achieve complete cytogenetic remission with interferon-alpha.
A substantial minority of patients with chronic myeloid leukaemia (CML) achieve a complete response to treatment with interferon-alpha (IFN-alpha), defined as the disappearance of Philadelphia chromosome positive metaphases or, for patients who are Philadelphia chromosome negative but BCR-ABL positive, the disappearance of the leukaemic clone as assayed by Southern blot. We have measured the levels of BCR-ABL transcripts in 20 such patients by quantitative PCR. Results were standardized for both quality and quantity of cDNA by quantification of ABL as an internal control. All 20 patients had evidence of residual disease; the median number of transcripts was 750/micrograms RNA (range 10-22,000) and the median BCR-ABL/ABL ratio was 0.17% (range 0.0008-3.6%). Our findings show that CML has not been eradicated in any patient and that the quantity of residual disease in complete responders may vary by as much as four orders of magnitude.
Adult↗
Stimulatory and inhibitory effects of iron on photodynamic inactivation of leukemia cells.
The influence of exogenous iron on merocyanine 540 (MC540)-sensitized photoinactivation of leukemia cells has been investigated. Irradiation of murine L1210 or human HL-60 cells (approximately 10(6)/mL in 1% serum/RPMI medium) with broadband visible light in the presence of MC540 (2 microM) resulted in a progressive loss of clonally assessed cell viability. When added to cells 30 min before irradiation, the low polarity chelate, ferric 8-hydroxyquinoline [Fe(HQ)2, 0.5 microM] stimulated dye-sensitized photokilling, whereas high polarity chelates such as ferric 8-hydroxyquinoline-5-sulfonate [Fe(HQS)2, 0.5 microM] or ferric ethylenediaminetetraacetate (Fe.EDTA, 0.5 microM) had no no effect. A striking reversal of Fe(HQ)2-enhanced photokilling was observed upon increasing the preirradiation incubation time with Fe(HQ)2 such that a marked resistance (relative to non-iron-treated controls) was evident after 24 h. Cells exposed for 24 h to Fe(HQS)2 or Fe.EDTA showed similar or even greater resistance to photokilling. Like phototoxicity, H2O2-induced cytotoxicity was enhanced after a 30 min exposure of cells to Fe(HQ)2 but strongly repressed after 24 h. Immunoblot (western) analysis, using a polyclonal antibody to ferritin, revealed that cells exposed to Fe(HQ)2 for 24 h contained at least 12 times as much ferritin heavy chain as non-Fe(HQ)2-treated controls. Preincubating cells with emetine, an inhibitor of protein synthesis, prevented both ferritin induction and the development of hyperresistance. These findings, along with the observation that exogenous apoferritin protected L1210 cells against photokilling, suggest a possible role for ferritin in iron-stimulated photoresistance.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Hip osteoarthritis and dysplasia in Chinese men.
OBJECTIVE: To estimate the prevalence of hip osteoarthritis (OA hip) and hip dysplasia in a sample of Hong Kong men who were unselected with respect to hip symptoms. METHODS: The postmicturition films of 999 men aged 60-75 years, consecutive attenders for intravenous urography between 1987 and 1990 at a regional hospital, were reviewed. OA hip was diagnosed as the occurrence of two or more features of OA using a modified version of the Kellgren and Lawrence scale, or a minimal joint space of 1.5 mm or less. Hip dysplasia was defined as a centre-edge angle of less than 25 degrees, or an acetabular depth of less than 9 mm. The results were compared with British data obtained by similar methods. RESULTS: In the Hong Kong sample, the proportion of men with two or more features of osteoarthritis in at least one hip was about 50% that of the men in the British study (5.4% and 11.0%, respectively). Severe joint space narrowing (of 1.5 mm or less) occurred in 0.7% of the hips in Hong Kong men, compared with 2% in the British men. The proportion of hips with centre-edge angles less than 25 degrees was 4.5% in Hong Kong, compared with 3.6% in Britain, and the prevalence of shallow acetabular depth was greater in Chinese (14.5%) than in the British (2.1%). Radiographic measures of hip dysplasia were not associated with minimal joint space. CONCLUSIONS: Our results have confirmed the lower prevalence of radiographic hip osteoarthritis in Hong Kong men compared with British men. However, acetabular dysplasia was as prevalent among Chinese men as in the British sample. This is evidence against the hypothesis that variations in the frequency of hip osteoarthritis are caused by differences in the occurrence of hip dysplasia.
Acetabulum↗
20-Hydroxyeicosatetraenoic acid is formed in response to EGF and is a mitogen in rat proximal tubule.
Hydroxyeicosatetraenoic acid (20-HETE) is a major cytochrome P-450-arachidonic acid metabolite in the rat kidney, and its synthesis along the nephron is specifically localized to the proximal tubule, where receptor density for epidermal growth factor (EGF) is the highest. EGF stimulated endogenous 20-HETE formation in a concentration and time-dependent manner, i.e., from 1.6 to 2.6 +/- 0.3 and 3.0 +/- 0.6 pmol 20-HETE.mg-1.min-1 at 10(-8) and 10(-7) M EGF, respectively. The effect of 20-HETE on proximal tubular cell proliferation was examined using primary cultures of rat proximal tubular cells and proximal tubular-derived cell lines, LLC-PK1 and opossum kidney OK. In both cell lines, 20-HETE increased thymidine incorporation into DNA with maximal effect at 10(-9) M. Addition of 20-HETE to serum-deprived LLC-PK1 or OK cells for 48 h caused a concentration-dependent increase in cell number with maximal effect at 10(-9) M. This effect was specific, as structurally similar eicosanoids such as 20-COOH-arachidonic acid, 19(R)-HETE, and 19(S)-HETE did not increase cell number. In 4-day primary cultures of proximal tubular cells, EGF (10(-9) M) and 20-HETE (10(-9) M) increased bromodeoxyuridine (BrdU) incorporation by 40 and 28%, respectively. Addition of both resulted in a twofold increase in BrdU incorporation. Although 20-HETE synthesis in cultured cells is greatly diminished with time, significant picomolar concentrations can be obtained in 4-day cultures. Addition of 17-octadecynoic acid (17-ODYA), an inhibitor of 20-HETE synthesis, significantly inhibited EGF-stimulated BrdU incorporation. The demonstrations that EGF stimulates proximal tubular 20-HETE production and that the latter is a potent mitogen to these cells suggests that 20-HETE may act as a mediator of the EGF effect on cellular growth in the proximal tubule.
Animals↗
The molecular biology of initiation of tooth eruption.
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Animals↗
Transcription and translation of CSF-1 in the dental follicle.
The dental follicle, a loose connective tissue sac which surrounds the unerupted tooth, is required for eruption to occur. Injection of colony-stimulating factor-1 (CSF-1) will accelerate molar eruption in rats, as well as stimulate tooth eruption in osteopetrotic rats. Utilizing in situ hybridization and reverse- transcription polymerase chain-reaction techniques, we show here that CSF-1 mRNA is present in vivo in the dental follicle of the first mandibular molar of the rat. Analysis of the molars from day 0 through day 10 post-natally demonstrates that the maximal expression of CSF-1 mRNA is at day 3 post-natally. Immunostaining also reveals that the CSF-1 mRNA is translated, with immunostaining for the CSF-1 itself, being heavy in early post-natal days and absent by day 9 postnatally. In view of the fact that there is a maximal influx of mononuclear cells (monocytes) into the dental follicle at day 3 post-natally--an influx which increases the numbers of osteoclasts needed to form a tooth eruption pathway--it is probable that the maximal expression of CSF-1 mRNA by day 3 post-natally contributes to this monocyte influx. Thus, this study establishes a relationship among a molecule (CSF-1), cell (monocyte), and tissue (dental follicle) that appear to play a major role in tooth eruption.
Animals↗
Arachidonic acid omega-hydroxylation and cytochrome P450 4A expression in the rat kidney.
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Aging↗
[Establishment of a human fetal thymocyte cell line and observation of its biological properties].
Thymocytes were isolated from a five month fetus after caesarean section and cultured in vitro. A cell line named human fetal thymocyte 8810 (HFT8810) was established and cultured continuously for 2 years in our lab, and grew well after recovery from the state of being frozen in liquid nitrogen. The HFT 8810 cells retained their ability to secrete thymosin after many generations in vitro culture.
Animals↗
Quantification of residual disease in Philadelphia-positive acute lymphoblastic leukemia: comparison of blood and bone marrow.
We designed a new semi-quantitative competitor-based PCR assay to assess the amount of p190 BCR-ABL mRNA in patients with Ph-positive ALL. Transcript numbers were compared in 29 paired specimens of blood and marrow collected contemporaneously from 18 patients at differing stages of disease. In general, the numbers of BCR-ABL transcripts detected in marrow in blood were not significantly different (p = 0.1). However, in four samples BCR-ABL transcripts (< 10-1000/micrograms RNA) were detected in the marrow while the blood was negative; the reverse, positive blood and negative marrow, was not seen. In a further three samples the number of BCR-ABL transcripts was more than 10-fold higher in the marrow. We measured the number of ABL transcripts/micrograms RNA in all samples as an internal standard in order to control for variations in sample quality and other parameters. For two out of the four discordant samples in which blood was PCR negative, the number of ABL transcripts/micrograms RNA detected in the marrow was substantially higher than in the blood, suggesting poor quality blood specimens. However, the ratio of BCR-ABL to ABL in marrow and blood was similar for the three discordant samples in which both tissues were PCR positive. We conclude that in general, blood and marrow contain similar BCR-ABL transcript numbers in Ph-positive ALL but some samples are discordant. Marrow is therefore the preferred tissue for residual disease studies. Quantification of ABL mRNA as an internal control is useful in the interpretation of competitive PCR data and may serve as a robust way to standardize results between laboratories.
Base Sequence↗
Cytochrome P450 arachidonic acid omega-hydroxylation in the proximal tubule of the rat kidney.
20-Hydroxy-5,8,11,14-eicosatetraenoic acid (20-HETE) is a major cytochrome P450-dependent arachidonate metabolite in the rat kidney. In the present study we characterized the formation of 20-HETE in the proximal tubule, the nephron segment with the highest concentration of cytochrome P450 activities, including P450 arachidonic acid metabolism. Freshly isolated tubules showed a basal formation of 20-HETE, implying that it is an endogenous constituent of the proximal tubule. Conversion of exogenous arachidonic acid to 20-HETE in proximal tubule homogenates was enzymatic and NADPH-dependent (i.e., 0 and 65.5 +/- 1.1 pmol/mg/min in the absence and presence of NADPH, respectively). That its formation was not affected by indomethacin but inhibited following preincubation with 17-ODYA (17-octadecynoic acid) and 7-ER (7-ethoxyresorufin) suggested that a P450 monooxygenase activity was involved in its synthesis. This was further strengthened by the demonstration that antibody raised against the rat cytochrome P450 4A1, a major fatty acid omega-hydroxylase isozyme, inhibited 20-HETE formation, suggesting the involvement of a P450 4A1 or P450 4A1-like activity in this reaction. Pretreatment of rats with clofibrate and dexamethasone, inducers of the P450 4A gene family, yielded a twofold increase in the proximal tubular synthesis of 20-HETE as well as an increase in P450 4A1 mRNA. These results, together with previous demonstrations that 20-HETE vasoconstricts isolated blood vessels, namely, renal microvessels, and affects tubular ion transport, suggest a role for 20-HETE in the regulation of renal vascular tone and transport functions and further stress the importance of understanding the regulation of 20-HETE synthesis in the kidney.
Animals↗
Recruitment with high physiological doses of estradiol preceding chemotherapy: flow cytometric and therapeutic results in women with locally advanced breast cancers--a Southwest Oncology Group study.
One theoretical method of increasing chemotherapeutic efficacy in breast cancer is to temporarily increase the number of tumor cells in cycle through hormonal recruitment prior to initiation of chemotherapy. In an effort to determine when and if this could be reliably accomplished, 50 women with locally advanced and/or metastatic breast cancer with known estrogen receptor (ER) status were entered into a serial breast biopsy study designed to measure increases in S-phase fraction (SPF) and proliferative index (PI; S + G2 + M) following administration of a high physiological dose of estrogen via estradiol vaginal suppositories prior to chemotherapy. Blood levels of estradiol were maintained in a range (0.5-5 nM) known to increase SPF in vitro. Compliance with suppository administration was monitored by serial blood sampling. Tumors were sampled at 0, 24, 48, 72, and/or 96 h. Thirty-one ER-positive and 9 ER-negative women had evaluable baseline biopsies and at least 1 subsequent biopsy. An increase was seen for SPF in 20 (69%) and for PI in 23 (79%) of 29 ER-positive patients at 48 h after estrogen initiation (95% confidence intervals, 49-85% for SPF and 60-92% for PI); similar increases were seen at 72 h. Median baseline SPF and PI values in ER-positive patients for whom increases were noted at 48 h were 6.2 and 8.5%, respectively. The median relative increases in these patients were 170 and 100%, respectively, at 48 h. The increases observed at 24 h in 4 (SPF) and 6 (PI) of the 9 ER-negative patients could have occurred by chance alone. Twenty-five of the 28 locally advanced (T4 and/or N2-3) patients achieved a complete response during combined modality treatment (estradiol-chemotherapy, mastectomy, and radiation). At a minimum follow-up time of 42 months, estimated 5-year progression-free and overall survivals are 30 and 49%, respectively, with a median time to progression of 35 months. Twenty-two women had metastatic disease (19 also had locally advanced disease). Thirteen had a complete or partial response, with a median duration of 12 months. Median progression-free and over-all survival times for all metastatic patients are 4 and 17 months, respectively. Estimated 5-year survival for metastatic disease patients is 27%. A high physiological dose of estrogen administered to patients with locally advanced ER-positive tumors can reliably increase the tumor SPF and PI within 48 h.(ABSTRACT TRUNCATED AT 400 WORDS)
Breast Neoplasms↗
Conformation of a peptide corresponding to T4 lysozyme residues 59-81 by NMR and CD spectroscopy.
The conformation, in solution, of a peptide corresponding to residues 59-81 from T4 lysozyme [LYS(59-81)] has been determined by 1H NMR and CD spectroscopy. This peptide spans the region corresponding to helix C in the crystal structure of T4 lysozyme. Secondary structure predictions indicated that the peptide would possibly be helical in an aqueous environment, but in a more hydrophobic environment the peptide would certainly adopt a helical conformation. This prediction was confirmed by the far-UV CD and NMR studies, which showed the peptide to be relatively unstructured in aqueous solution and significantly helical in the presence of either TFE or SDS micelles, although the 1H NMR results did give some indication of the presence of nascent helix in aqueous solution. For LYS(59-81), in TFE, the three-dimensional structure derived from the NMR data showed that the helix had a more pronounced curvature than the gradual bend observed in the crystal structure.
Amino Acid Sequence↗
Thermal conductivity of KH2PO4 in an applied electric field.
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Journal Article↗
Relapse of chronic myeloid leukemia after allogeneic bone marrow transplant: the case for giving donor leukocyte transfusions before the onset of hematologic relapse.
Fourteen patients with chronic myeloid leukemia (CML) relapsing after allogeneic bone marrow transplant (BMT) were treated with leukocyte transfusions from the original marrow donor (sibling, n = 9; volunteer unrelated, n = 5). The relapse was defined at the molecular level in two cases, cytogenetically in five cases and hematologically in seven cases. Ten patients responded, seven of seven patients with cytogenetic/molecular relapse compared with three of seven with hematologic relapse (P < .03). All five recipients of cells from unrelated donors responded. Eight of the 10 responders have achieved polymerase chain reaction-negative status and this persisted in three patients for more than 2 years; no responder has shown sign of relapse. Reversible marrow aplasia occurred in two patients, both treated in hematologic relapse. Severe graft-versus-host disease occurred in four patients and was fatal in one. We confirm previous reports that donor leukocyte transfusions are effective in the management of CML in relapse after BMT. In this series, therapeutic intervention before the onset of hematologic relapse was associated with an increased likelihood of response and no marrow aplasia.
Adult↗
Characterization of the human gene encoding LBR, an integral protein of the nuclear envelope inner membrane.
We have characterized the human gene encoding LBR, an integral protein of the nuclear envelope inner membrane. Restriction mapping shows that the transcription unit spans approximately 35 kilobases. A transcription start site is located approximately 4 kilobases 5' to the translation initiation codon, and an RNA splice of 3863 bases occurs in the 5'-untranslated region to generate mature HeLa cell mRNA. 5' to the identified transcription start site are two CCAAT sequences and potential recognition sites for several transcription factors including Sp1, AP-1, AP-2, and NF-kB. There are 13 protein coding exons in the LBR gene. LBR's nucleoplasmic domain is encoded by exons 1-4, and its hydrophobic domain, with eight putative transmembrane segments, is encoded by exons 5-13. The hydrophobic domain is homologous to three yeast polypeptides, suggesting that this higher eukaryotic gene could have evolved from recombination between a gene that encoded a soluble nuclear protein and a membrane protein gene similar to those in yeast. These results are the first to demonstrate the structural organization of a vertebrate gene encoding an integral membrane protein of the nuclear envelope that may be a member of a family of polypeptides conserved in evolution.
Amino Acid Sequence↗
Symptomatic double-channel pylorus. Successful treatment with a biliary sphincterotome.
A patient with a previous vagotomy and pyloroplasty was evaluated for symptoms of gastric outlet obstruction. Endoscopy revealed a thick, fibrous bridge that created a dual-channel pylorus. Symptomatic improvement was not achieved with balloon dilatation. Surgery was avoided by dividing the tissue bridge endoscopically with a sphincterotome. Since reestablishing a normal pyloric aperture, the patient's symptoms have been alleviated. This is the first description of this minimally invasive technique in the management of a symptomatic double-channel pylorus.
Endoscopy, Digestive System↗