Wild-type gas vesicle formation requires at least ten genes in the gvp gene cluster of Halobacterium halobium plasmid pNRC100

To study the functions of the 13 gvp genes, gvpMLKJIHGFEDACN, on plasmid pNRC100 of Halobacterium halobium in gas vesicle formation, we carried out linker scanning mutagenesis of the gene cluster. We constructed a 24.5-kb Escherichia coli-H. halobium shuttle plasmid, pFL2, containing the gvp gene cluster and introduced a kanamycin resistance (kappa) cassette into each gene (except for gvpA). Transformation of H. halobium SD109, which had the entire gvp gene cluster deleted, with pFL2 and mutated pFL2 derivatives showed that while the unmutated gene cluster successfully programmed gas vesicle formation, derivatives with insertion of the kappa cassette in any of the gvp genes, except gvpM, did not lead to production of normal gas vesicles. Insertions in gvpL, -K, -J, -I, and -F resulted in a complete block in gas vesicle synthesis, while insertions in gvpH, -G, -E, -D, -C, and -N resulted in greatly reduced gas vesicle synthesis. In most cases, the block in gas vesicle synthesis did not result from polar effects, since similar results were obtained for derivatives of the insertion mutants in which most of the internal portion of the kappa cassette was deleted and only small (15 to 54-bp) insertions remained. The only exceptions were for gvpH and gvpD, where deletion of the internal portion of the kappa insertions resulted in phenotypic reversion. Electron microscopic analysis of the kappa mutants revealed that interruptions of gvpC and gvpN result in the formation of smaller gas vesicle than in the wild type, while interruptions of gvpF, -G, -H, -J, -K, and -L produce no discernible vesicle intermediates. These results indicate the gvpA, -C, and -N, which have the rightward transcriptional orientation, encode structural proteins, with gvpC and gvpN necessary for late stages of vesicle formation, and gvpL, -K, -J, -I, -H, -G, and -F, which have the leftward transcriptional orientation encode proteins involved in early steps in the assembly of gas vesicles.

Goblet cell carcinoid of the appendix

BACKGROUND

Over the past 15 years, a variant of appendiceal carcinoid has been recognized which is not widely known to the general surgeon. This tumor, variously labeled adenocarcinoid or goblet cell carcinoid, has a more aggressive natural history than classic appendiceal carcinoids and requires a different surgical approach.

PATIENTS AND METHODS

A survey of the tumor registries of 10 hospitals identified 7 female and 2 male patients with goblet cell carcinoid of the appendix between 1983 and 1993. The clinical data of these patients were reviewed.

RESULTS

Median age was 58 years (range 31 to 73). Clinical presentation followed two distinct patterns: acute onset suggestive of appendicitis or chronic symptoms associated with a pelvic mass. In no case was the diagnosis suspected preoperatively or established intraoperatively. Four patients with discrete distal appendiceal tumors treated with appendectomy are alive without evidence of disease 2 to 11 years since their diagnoses. The 5 patients with diffuse appendiceal involvement all had intra-abdominal metastases. Four are dead of disease at intervals from 5 months to 2 years postdiagnosis.

CONCLUSIONS

Goblet cell carcinoids are a distinct clinical and pathologic entity with variable malignant potential. Patients with diffuse appendiceal involvement require aggressive surgery as part of multimodal therapy.

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.

Cloning and sequencing of an endo-beta-1,4-glucanase gene mcenA from Micromonospora cellulolyticum 86W-16

Endo-beta-1,4-glucanase gene mcenA of Micromonospora cellulolyticum 86W-16 was cloned, and the nucleotide sequence was determined. An open reading frame (ORF) of 1374 bases, coding for a peptide (McenA) of 457 amino acids and 46,742 Da, was found. It is preceded by a Gram-positive type of ribosome-binding site and followed by an imperfect inverted repeat. A putative signal peptide containing 23 amino acids is at the N-terminus and a linker region possessing 37 amino acids is in the midpart of McenA. The N-half of McenA functions as the catalytic domain and the C-half might serve as a cellulose-binding domain (CBD). Deletion of the latter did not decrease the CMCase activity of McenA. Significant similarity (70%) was found between the amino acid sequences of McenA and MbcelA, an endoglucanase from Microbispora bispora.

Trisomy 11 and other nonrandom trisomies in congenital fibrosarcoma

Chromosome studies in a 7-week-old female infant with an intraabdominal malignant fibrosarcoma showed a hyperdiploid karyotype of 50,XX, +der(6)del(6)(p23)add(6)(q11), +8, +10, +11,add(12)(p13). Trisomy 11 appears to be a nonrandom primary cytogenetic abnormality in the congenital or infantile form of this mesenchymal tumor and is also a nonrandom gain in congenital mesoblastic nephroma. A possible developmental link between these two mesenchymal tumors, mediated by a gene or genes on chromosome 11 is postulated.

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)

Detection of residual leukaemia more than 10 years after allogeneic bone marrow transplantation for chronic myelogenous leukaemia

The clinical status of a homogeneous cohort of long-term survivors of allogeneic marrow transplantation was assessed and residual leukaemia was studied by reverse transcription polymerase chain reaction for leukaemia specific BCR-ABL mRNA. The group comprised 34 consecutive patients with CML in chronic phase treated by chemoradiotherapy and transplantation of bone marrow from HLA-identical sibling donors between February 1981 and December 1983 in the joint Hammersmith-Northwick Park programme. The probability of survival at 10 years was 59 +/- 17%. Eighteen of the 19 surviving (95%) patients have Karnofsky scores of 90 or 100% indicative of a good performance status. One of the survivors had evidence of relapse 6.5 years after transplant but has since been restored to complete remission by treatment with interferon-alpha followed by donor leucocyte transfusions. Surprisingly, 2 of the 19 patients who have been in remission for over 10 years have molecular evidence of persisting leukaemic cells. Quantification by competitive PCR indicated that the malignant clone persisted at low levels. The data suggest that the majority of long-term survivors after BMT for CML are in good health and may be regarded as cured. Some long-term survivors, however, may still harbour residual leukaemic cells and continued monitoring for late relapse is warranted. Late relapse is amenable to further therapy with leukocyte transfusions from the original marrow donor.

Aplasia after donor lymphocyte infusion (DLI) for CML in relapse after sex-mismatched BMT: recovery of donor-type haemopoiesis predicted by non-isotopic in situ hybridization (ISH)

We report a patient with CML in relapse after a sex-mismatch bone marrow transplant who was treated with donor lymphocyte infusions and developed severe marrow aplasia 3 months later. As cytogenetic analysis at this point was not possible because of the very low number of marrow cells available, we used in situ hybridization (ISH) for sex chromosomes and the BCR/ABL gene together with quantitative PCR to monitor the patient's response. The results suggest that recovering haemopoiesis was derived from donor cells and contributed to the decision not to transfuse donor marrow cells on a second occasion.

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.

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.

Selective RNA editing and subunit assembly of native glutamate receptors

RNA editing and subunit assembly of ionotropic glutamate receptors (GluRs) were examined in an oligodendrocyte progenitor cell line, CG4, which expresses GluR2-GluR4, GluR6, GluR7, KA1, and KA2. AMPA-evoked currents rapidly desensitize, whereas kainate-evoked currents contain a steady-state component with a nearly linear current-voltage relation and a fast desensitizing component that is inwardly rectifying. The Q/R site is edited > 95% to the arginine codon in GluR2(Q607) mRNA, and < 5% in GluR6(Q621) mRNA. Immunoprecipitation experiments demonstrate that GluR6 and/or GluR7 subunits assemble with KA2, but not with GluR2-GluR4. These results indicate that oligodendrocyte progenitor cells selectively edit and assemble glutamate receptors into at least two functionally and structurally distinct heteromeric channels.

Regulation and localization of colony-stimulating factor-1 mRNA in cultured rat dental follicle cells

Cultured dental follicle cells from rat mandibular molars transcribe colony-stimulating factor-1 (CSF-1) mRNA as determined by reverse-transcription polymerase chain reaction. In turn, the CSF-1 mRNA appears to be translated, as seen by immunoperoxidase staining. Interleukin 1 alpha (IL-1 alpha) stimulates increased transcription of the CSF-1 gene in a concentration- and time-dependent manner. Moreover, CSF-1 itself has an autocrine effect on transcription of the CSF-1 gene. Because others have shown that in vivo injection of CSF-1 accelerates tooth eruption and because the dental follicle is required for eruption to occur, this study demonstrates the possible relation between CSF-1 and the follicle; namely, the source of CSF-1 for tooth eruption might be the dental follicle. In turn, regulation of gene expression for CSF-1 by IL-1 alpha and CSF-1 may play a part in signalling the onset of tooth eruption.

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.

Bleaching of membrane-bound merocyanine 540 in conjunction with free radical-mediated lipid peroxidation

The lipophilic dye merocyanine 540 (MC540) can photosensitize potentially lethal cell membrane damage as well as its own degradation (bleaching). Photobleaching in a test membrane, the human erythrocyte ghost has been examined. White light irradiation of MC540-sensitized ghosts resulted in lipid hydroperoxide (LOOH) formation, low-level thiobarbituric acid (TBA) reactivity, and dye bleaching (A568 decay). When the reaction was carried out in the presence of ascorbate (AH-), and added Fe3+, there was a large enhancement of TBA reactivity (indicative of free radical-mediated lipid peroxidation) and concomitant increase in the rate of photobleaching. Rapid bleaching also occurred when MC540 was incubated in the dark with ghosts that had been photoperoxidized with another dye (a phthalocyanine) and then exposed to AH-. The extent of bleaching in this system was found to be proportional to the starting level of LOOH. Like the wave of free radical lipid peroxidation that accompanied it, dye bleaching in AH(-)-treated, preperoxidized ghosts was stimulated by supplemental Fe3+, inhibited by desferrioxamine or butylated hydroxytoluene (BHT), but unaffected by catalase or superoxide dismutase. From this and related evidence, we deduce that: (1) in the absence of Fe3+/AH-, photoperoxidation and photobleaching occur independently and are nonradical, singlet oxygen-mediated processes; and (2) in the presence of Fe3+/AH-, 1-electron reduction of photogenerated LOOHs results in a surge of lipid peroxidation that amplifies dye loss via free radical processes. MC540 bleaching might be exploited as a relatively simple and sensitive indicator of lipid autoxidation in isolated membranes and cells.

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.

Both open and closed NMDA receptor channels desensitize

Desensitization of NMDA receptors was studied at the single-channel level using outside-out patches taken from rat hippocampus CA neurons maintained short term in culture. The amount of desensitization that accumulated as a function of time during the application of NMDA (2.5 microM) was measured by the response to the rapid application of NMDA at a high concentration (100 microM). Records were sorted into two classes: those in which no openings were detected during the application of 2.5 microM NMDA, and those in which some channel openings occurred. Analysis of these data reveals that some desensitization accumulated when no channels opened, but that more desensitization developed when channels opened. The observations indicate that channels can pass from the closed state to the desensitized state, but that desensitization occurs more rapidly from the open state.

Detection of proteins and sialoglycoproteins in polyacrylamide gels using eosin Y stain

An eosin Y staining technique that permits detection of various proteins, including membrane sialoglycoproteins, in polyacrylamide gels is described. The sensitivity of the eosin Y staining method is comparable to silver staining. In addition, there is an added advantage of the antigenicity of the stained proteins being retained in a Western blot. Details of the procedure to obtain optimal staining results are described.

A comparison of the sensitivity of blood and bone marrow for the detection of minimal residual disease in chronic myeloid leukaemia

We have sought to determine whether peripheral blood or bone marrow is more sensitive for assessment of minimal residual disease in chronic myeloid leukaemia (CML). Contemporaneous blood and marrow specimens were taken from 21 patients at various times after allogeneic bone marrow transplant (BMT) and from one patient in complete cytogenetic remission on alpha-interferon. Samples were analysed for evidence of BCR-ABL mRNA by RT-PCR: four were PCR negative and 19 PCR positive. Results with blood and marrow were concordant in all cases. BCR-ABL transcripts were quantified in PCR-positive samples using a competitive PCR titration assay. Results ranged from < 10 to 2 x 10(6) BCR-ABL transcripts/micrograms RNA. In all 19 cases a high degree of concordance in BCR-ABL levels with blood and marrow (r = 0.99) was found. We conclude that either tissue may be used for residual disease studies after BMT for CML.

Cytoprotection against merocyanine 540-sensitized photoinactivation of the Na+,K(+)-adenosine triphosphatase in leukemia cells: glutathione and selenoperoxidase involvement

When irradiated with broad-band visible light in the presence of merocyanine 540 (MC540), murine leukemia L1210 cells grown under selenium-deficient conditions (Se(-) cells) accumulated lipid hydroperoxides and lost viability more rapidly than selenium-satisfied (Se(+) cells). These findings suggest that cytoprotection against photoperoxidation and photokilling is mediated at least in part by selenoperoxidase (SePX) action. Similar protection against photoinactivation of an intrinsic membrane enzyme, the Na+,K(+)-ATPase, has been observed. Thus, irradiation of MC540-sensitized Se(-) cells resulted in an immediate and progressive inactivation of ouabain-sensitive Na+,K(+)-ATPase; by contrast, activity loss in Se(+) cells was preceded by a prominent lag. Enzyme photo-inactivation in Se(-) cells was inhibited by ebselen, an SePX mimetic, confirming that SePX(s) is (are) involved in natural protection. Desferrioxamine treatment (iron sequestration/inactivation) resulted in higher hydroperoxide levels and slower Na+,K(+)-ATPase inactivation during MC540/light exposure, whereas ferric-8-hydroxyquinoline treatment (iron supplementation) had the opposite effect. Thus, iron appears to play an important role in both of these processes. In contrast, photoinactivation of another intrinsic enzyme in L1210 cells, acetylcholinesterase (AChE), was unaffected by selenium or iron manipulation. On the basis of these findings, we propose that lipid peroxidation plays an important role in the photoinactivation of Na+,K(+)-ATPase, but not AChE. This is consistent with the fact that Na+,K(+)-ATPase's active site lies within the membrane bilayer, whereas AChE's active site lies outside the bilayer.

Endoscopic ultrasound-guided fine needle aspiration of pancreatic carcinoma

Endoscopic ultrasound (EUS) is reported to be the single best modality for visualizing small pancreatic carcinomas. Whereas tissue diagnosis by fine needle aspiration (FNA) can be performed with computed tomography (CT) or transabdominal ultrasound guidance, the diagnostic accuracy is limited by the ability of these modalities to visualize the lesion. Real time EUS-guided fine needle aspiration has recently been reported as a new diagnostic modality. The application of EUS-guided FNA in the diagnosis of small pancreatic carcinoma has not been reported. We present a case in which transduodenal EUS-guided FNA was successful in establishing a definitive tissue diagnosis of pancreatic carcinoma in a 1.6-cm lesion in the head of the pancreas. This case along with a review of the literature highlights the great potential of this new modality in the diagnosis of pancreatic carcinoma.

Synovial cyst of dens causing spinal cord compression. Case report

We report a rare case of synovial cyst of the dens (odontoid process) in a 61 year old women with no previous history of trauma. She had progressive symptoms of 1 year's duration due to spinal cord compression. Magnetic resonance imaging of cervical spine revealed a large mass posterior to the dens which was compressing the spinal cord near the cervicomedullary junction. This lesion was at first considered radiologically to represent an exuberant pannus formation or a meningioma of the foramen magnum, but subsequent surgical intervention and pathological examination revealed that it was a synovial cyst. Similar cases reported in the literature are reviewed and discussed.