PubMed Health⌕ Search

Biomedical subjects

D Moore

Publications and source records attributed to D Moore.

At least 271 records · Page 15Linked to original sources
PubMed1988

Ammonium ions and glutamine inhibit sporulation of Coprinus cinereus basidia assayed in vitro.

Basidia of Coprinus cinereus (Schaeff.:Fr) S. F. Gray are committed to their developmental pathway, continuing through meiosis and sporulation even when excised from their parental fruit body. A technique is described which permits this in vitro differentiation to be used as a rapid, small-scale bioassay for chemicals which interfere with these morphogenetic processes. Of a range of compounds tested, only ammonium and glutamine, and some structural analogues, were able to inhibit basidium differentiation. Growth was not inhibited; instead the differentiation inhibitors caused vegetative hyphal tips to grow out from regions of the basidial apparatus expected to be in active growth during sporulation. Depending on the stage reached at the time of exposure to the inhibitors, vegetative hyphal tips emerged from the four apical sites for sterigmata, from the tips of sterigmata, from partially formed or abnormal spores, and from the basal regions of the basidium from which paraphyses would be expected to arise. The experiments show that ammonium ions and glutamine halt meiocyte differentiation. Reports of similar effects in other organisms, animals and plants as well as fungi, may imply that sporulation events are generally sensitive to ammonium inhibition.

Agaricales↗
PubMed1988

Semisynthetic pyrrolizidine alkaloid N-oxide antitumor agents. Esters of heliotridine.

The C-9 and C-7 monoesters and C-7, C-9 diesters of heliotridine with (S)-(+) and (R)-(-)-2-hydroxy-2-phenylbutyric acid were prepared, converted into their N-oxides, and compared with the corresponding C-9 monoesters of retronecine in the in vivo P388 lymphocytic leukemia screen. Relative in vitro cytotoxicities of some of the free bases and their corresponding N-oxides were also measured against the A204 rhabdomyosarcoma cell line by using the soft agar colony forming assay. Stereochemistry at C-7 of the necine and at C-2' of the necine acid appears to have a significant effect on the antitumor activity in this system. In the heliotridine series, the configuration of the necic acid has a pronounced effect on the site selectivity (C-7 vs C-9) in esterification with carbodiimidazole. An explanation for this site selectivity is offered.

Animals↗
PubMed1988

In vitro susceptibilities of Nocardia species to newer antimicrobial agents.

The in vitro activities of various quinolones, two newer cephalosporins, and imipenem against 23 strains of Nocardia asteroides, 4 strains of Nocardia brasiliensis, and 4 strains of Nocardia caviae were determined by an agar dilution method. PD-117558, a newer carboxyquinolone, and imipenem were the most active agents tested, inhibiting 90% of N. asteroides isolates at an MIC of 2 micrograms/ml. Of the 23 strains of N. asteroides, 15 were susceptible to cefpirome and 10 were susceptible to ciprofloxacin. The N. brasiliensis and N. caviae strains were very susceptible to PD-117558 (MIC, less than or equal to 1 microgram/ml), moderately susceptible to ciprofloxacin, and resistant to most of the other tested drugs.

Anti-Bacterial Agents↗
PubMed1988

An analysis of structural aberrations in human sperm chromosomes.

We have analyzed structural aberrations in 5,000 sperm chromosome complements obtained from 20 men over a 5-yr period by fusion of human sperm with hamster eggs. Detailed data are presented on 366 abnormal cells with 379 analyzable breakpoints. The frequency of cells with structural aberrations ranged from 1.9% to 14.5% among donors; this interindividual variability was statistically significant (p less than 0.0001). In contrast, repeat samples from individual men showed no significant variation over time. The number of sperm chromosome sets processed per hamster egg had no effect on the frequency with which structural aberrations occurred, nor were sperm chromosome abnormalities altered by varying capacitation or culture conditions. The spectrum of structural aberrations observed in human sperm chromosomes and a chi-square analysis of breakpoints based on DNA content are presented. Although human sperm chromosome abnormalities were visualized with a cross-species system, we believe that they represent an inherent, biologically significant phenomenon.

Animals↗
PubMed1987

Characterization of hyaluronate binding proteins isolated from 3T3 and murine sarcoma virus transformed 3T3 cells.

A hyaluronic acid binding fraction was purified from the supernatant media of both 3T3 and murine sarcoma virus (MSV) transformed 3T3 cultures by hyaluronate and immunoaffinity chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis resolved the hyaluronate affinity-purified fraction into three major protein bands of estimated molecular weight (Mr,e) 70K, 66K, and 56K which contained hyaluronate binding activity and which were termed hyaluronate binding proteins (HABP). Hyaluronate affinity chromatography combined with immunoaffinity chromatography, using antibody directed against the larger HABP, allowed a 20-fold purification of HABP. Fractions isolated from 3T3 supernatant medium also contained additional binding molecules in the molecular weight range of 20K. This material was present in vanishingly small amounts and was not detected with a silver stain or with [35S]methionine label. The three protein species isolated by hyaluronate affinity chromatography (Mr,e 70K, 66K, and 56K) were related to one another since they shared antigenic determinants and exhibited similar pI values. In isocratic conditions, HABP occurred as aggregates of up to 580 kilodaltons. Their glycoprotein nature was indicated by their incorporation of 3H-sugars. Enzyme-linked immunoadsorbent assay showed they were antigenically distinct from other hyaluronate binding proteins such as fibronectin, cartilage link protein, and the hyaluronate binding region of chondroitin sulfate proteoglycan. The apparent dissociation constant of HABP for hyaluronate was approximately 10(-8) M, and kinetic analyses showed these binding interactions were complex and of a positive cooperative nature.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Remissions in hairy-cell leukemia with pentostatin (2'-deoxycoformycin).

The Eastern Cooperative Oncology Group conducted a study of pentostatin (2'-deoxycoformycin) in 37 patients with hairy-cell leukemia. Among the 27 patients who met all the study's entry criteria, the response rate was 96 percent, with 16 patients (59 percent) entering complete remission and 10 patients (37 percent) partial remission. In one patient no response was observed. These results were not significantly changed by the inclusion of nine additional patients who were found retrospectively not to have fulfilled the entry criteria. When complete remission was attained, maintenance therapy was not given. Despite this, no patient has had a relapse, and the duration of complete remission ranges from 1 to 375 days. Pentostatin appears to be equally effective in untreated patients and in those who have progressive disease after splenectomy or after both splenectomy and treatment with interferon. Whether pentostatin is superior to splenectomy or interferon as therapy for hairy-cell leukemia will have to be assessed by direct comparison in randomized studies. Lengthy follow-up will be required to determine a median duration for the responses of hairy-cell leukemia to pentostatin.

Antineoplastic Agents↗
PubMed1987

Neural control of a cyclic postural behavior in the crayfish, Procambarus clarkii: the pattern-initiating interneurons.

As part of its repertoire of defensive behaviors, the crayfish, Procambarus clarkii, may respond to mildly threatening tactile or visual stimuli from the front of its body by walking backwards. During this behavior, the abdomen undergoes complex cyclical movements involving flexion and extension of the postural musculature which cause the tail to alternately contact and withdraw from the substrate. Intracellular neuropil recordings and dye injections were used to search for the interneurons responsible for initiating this postural motor pattern in the crayfish abdomen. Several diverse morphological types of interganglionic pattern-initiating (PI) interneurons were found. Each interneuron, when driven intracellularly, was capable of eliciting the same motor program, in its entirety, throughout the abdominal nerve cord. During pattern generation, PI interneurons exhibited a burst of spikes preceding the motor output. Silencing single PI interneurons with hyperpolarizing current during pattern generation failed to affect the motor program, indicating a redundancy of pattern-initiating function. The observations of extensive dye-coupling with other parallel axons, consistent dye-coupling with other identified cells in the pattern-initiating system, and the presence of multiple spike amplitudes in the bursts suggested electrotonic coupling among the PI interneurons. An additional group of interganglionic interneurons, the partial pattern-initiating (PPI) interneurons, were found to comprise a significant subset of the pattern-initiating system. As with the PI cells, the PPI interneurons exhibited a complex burst of spikes just preceding the patterned motor program. However, the PPI interneurons were only capable of eliciting an incomplete, though recognizable, postural motor pattern. Silencing any PPI interneuron during pattern generation caused a deficit in the motor pattern, indicating either an absence or lesser degree of functional redundancy within the PPI interneuron population compared to that occurring within the PI interneuron group. We conclude that a large number of PI interneurons are presynaptic to a relatively small group of PPI interneurons which, in turn, conduct pattern-initiating signals to the ganglionic oscillators. Our results indicate that pattern-initiation is accomplished through a command system involving multiple command elements organized in a coordinated interganglionic network.

Animals↗
PubMed1987

Analysis of Escherichia coli K12 F factor transfer genes: traQ, trbA, and trbB.

The genes that encode the transfer properties of plasmid F, the fertility factor of Escherichia coli K12, are known to be clustered over a large, 33.3-kb segment of F DNA. As the central segment of the transfer region has not previously been well characterized, we constructed a detailed restriction map of the large F EcoRI DNA fragment, fl, and isolated a series of plasmid derivatives that carry various overlapping segments of this F tra operon DNA. We also analyzed the protein products of those clones that carried DNA segments extending over the region between traF and traH. This region was known to include traQ, a gene required for efficient conversion of the direct product of traA to the 7000-Da pilin polypeptide. We identified the traQ product as a polypeptide that migrates as a 12,500-Da protein on sodium dodecyl sulfate-polyacrylamide gels. We also detected the products of two other new genes that we have named trbA and trbB. These polypeptides migrate with apparent molecular weights of 14,200 and 18,400, respectively. Analysis of plasmid deletion derivatives that we constructed in vitro shows that these genes map in the order traF trbA traQ trbB traH. The presence of a plasmid carrying a small 0.43-kb fragment that expressed only the 12,500 traQ product caused the traA product of a co-resident compatible plasmid to be converted to the 7000-Da pilin polypeptide, demonstrating that TraQ is the only tra operon product required for this step of F-pilin biosynthesis.

Bacteriophage lambda↗
PubMed1987

Familial renal abnormalities associated with the oligohydramnios tetrad secondary to renal agenesis and dysgenesis.

Thirty-four families of index cases with the oligohydramnios tetrad secondary to renal agenesis/dysgenesis were screened for renal abnormalities using Real Time ultrasonography. The index cases were separated into two groups. Group 1 consisted of cases of perinatally lethal renal disease and Group 2 of cases of renal dysgenesis secondary to the urethral obstruction malformation. Renal ultrasound screenings of 23 families in Group 1 demonstrated two previously unidentified cases of unilateral renal agenesis in siblings. Screening of 11 families in Group 2 revealed one sibling with a hydronephrotic kidney and one parent with an ectopic pelvic kidney. There is a recurrence risk of 3.5-5% in families with perinatal lethal renal disease and an increased risk of silent renal anomalies in first degree family members. The recurrence risk is low in families of infants with renal dysgenesis secondary to the urethral obstruction malformation, but immediate family members are at increased risk of structural and functional urinary anomalies. Routine renal ultrasound screening of first degree relatives of infants with lethal renal agenesis and dysgenesis is recommended.

Amniotic Fluid↗
PubMed1987

Location of F plasmid transfer operon genes traC and traW and identification of the traW product.

As part of an analysis of the conjugative transfer genes associated with the expression of F pili by plasmid F, we have investigated the physical location of the traC and traW genes. We found that plasmid clones carrying a 2.95-kilobase EcoRI-EcoRV F transfer operon fragment were able to complement transfer of F lac traC mutants and expressed an approximately 92,000-dalton product that comigrates with TraC. We also found that traW-complementing activity was expressed from plasmids carrying a 900-base-pair SmaI-HincII fragment. The traW product was identified as an approximately 23,000-dalton protein. The two different F DNA fragments that expressed traC and traW activities do not overlap. Our data indicate that the traC gene is located in a more-tra operon promoter-proximal position than suggested on earlier maps and that traW is distal to traC. These results resolve a long-standing question concerning the relationship of traW to traC. The clones we have constructed are expected to be useful in elucidating the role of proteins TraC and TraW in F-pilus assembly.

Bacterial Proteins↗
PubMed1987

Analysis of transfer genes and gene products within the traB-traC region of the Escherichia coli fertility factor, F.

A series of plasmids that carry overlapping segments of F DNA encoding the genes in the traB-traC interval was constructed, and a restriction enzyme map of the region was derived. Plasmids carrying deletions that had been introduced at an HpaI site within this interval were also isolated. The ability of these plasmids to complement transfer of F lac plasmids carrying mutations in traB, traV, and traW, and traC was analyzed. The protein products of the plasmids were labeled in UV-irradiated cells and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. These analyses showed that the product of traV is a polypeptide that migrates with an apparent molecular weight of 21,000. It was not detected when [35S]methionine was used to label plasmid products, but was readily detected in 14C-amino acid labeling experiments. A 21,500-dalton product appeared to stem from the region assigned to traP. A 9,000-dalton product was found to stem from a locus, named traR, that is located between traV and traC. No traW activity could be detected from the region of tra DNA examined. Our data also indicated that traC is located in a more promoter-proximal position than suggested on earlier maps. The plasmids constructed are expected to be useful in studies designed to identify the specific functions of the traB, -P, -V, -R, and -C products.

Autoradiography↗
PubMed1987

Morbidity after percutaneous liver biopsy.

The safety of percutaneous liver biopsy with a 1.2 mm Menghini needle in infants aged one year or less was investigated. One hundred and eighty four procedures performed from 1975 to 1985 were reviewed. There were no deaths or major complications within 48 hours associated with the procedure. In five instances specific complications occurred: a drop in haemoglobin concentration (three), transient hypotension (one), and haematoma at the biopsy site (one). The result of liver biopsy was diagnostic in 83% of cases, compatible with unspecified metabolic disease in 8%, and normal or not diagnostic in 9%. This study suggests that percutaneous liver biopsy can be performed with relative safety in small infants if coagulation is normal and there are no major contraindications, and the results yield important diagnostic information which cannot be obtained using less invasive procedures.

Biopsy, Needle↗