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Biomedical subjects

C Gribbin

Publications and source records attributed to C Gribbin.

14 recordsLinked to original sources
PubMed2001

Radiologic placement of a low profile implantable venous access port in a pediatric population.

PURPOSE: To evaluate the feasibility and complications of placement of a low-profile venous access port in the chest in children requiring long-term venous access. METHOD: A low-profile peripheral arm port (PAS port; Sims Deltec, St. Paul, MN, USA) was implanted in the chest in 22 children over a 4-year period. The mean age of the study group was 6 years (range: 9 months to 20 years). Ports were placed for the administration of chemotherapy, hyperalimentation and frequent blood sampling. Sonographic guidance was used to access the internal jugular or subclavian vein in each case. A review of all inpatient and outpatient charts was undertaken to assess catheter performance and complications. RESULTS: Access to the central venous circulation was successfully achieved in each case without complication. Ports remained implanted for 6579 catheter-days (mean: 299 days). Ten ports have been removed. Of three patients (13%) experiencing device-related infections (0.45 infections/1000 catheter days), two (9.1%) were unresponsive to antibiotics and removed (0.3 infections/1000 catheter days). One port was removed because of pain in the shoulder adjacent to the port implantation site. One port was removed because of difficult access. The final port was removed in order to place a dual-lumen catheter prior to bone marrow transplant. Twelve ports remain implanted. Aspiration occlusion occurred in four patients (18%). Deep venous thrombosis did not occur in any patient. CONCLUSION: Low-profile chest ports placed by interventional radiologists in the interventional radiology suite can be placed in children as safely as traditional chest ports placed in the operating room. The incidence of infection, venous thrombosis and aspiration occlusion is comparable to that of ports placed operatively.

Adolescent↗
PubMed1998

Chronology of events in the first cell cycle of the polyspermic egg of the domestic fowl (Gallus domesticus).

The nuclear population in the polyspermic egg of the domestic hen was examined in whole-mount preparations of the germinal disc. The numbers of nuclei varied in groups of hens from averages of 5.9 to 26, depending on days from insemination. Changes in development from initial formation of pronuclei to the early mitoses of the zygote nucleus were staged according to the position of the egg in the oviduct. The findings substantiated earlier accounts on the timing of the apposition of the parental pronuclei towards the end of the first cell cycle. Additionally, analysis of the spatial distribution of accessory spermatozoal nuclei showed a slight, but significant, dispersal from a clustered arrangement at this time.

Animals↗
PubMed1995

Expression of genes encoding bone morphogenetic proteins and sonic hedgehog in talpid (ta3) limb buds: their relationships in the signalling cascade involved in limb patterning.

The chicken mutant talpid3 (ta3) has polydactylous limbs with up to 7-8 morphologically similar digits. This lack of antero-posterior polarity in digit pattern is correlated with symmetrical expression of genes of the HoxD complex. We determined the distribution of polarizing activity in limb buds of the chick mutant ta3 by assessing the ability of mesenchyme from various positions along the antero-posterior axis to induce digit duplications when grafted anteriorly into a normal limb. Cells with highest polarizing activity were found at the posterior margin of the wing as in the polarizing region of normal limb buds. However, in contrast to normal limb buds, ta3 anterior mesenchyme also had low polarizing activity. Application of retinoic acid or a polarizing region graft to the anterior of ta3 limb buds changed digit morphology but did not induce digit duplications or digits with any characteristic a-p pattern. To determine which genes are associated with polarizing activity and which are associated with patterning of the digits, we examined expression of the genes Sonic hedgehog (shh), Bmp-2, and Bmp-7, whose expression is normally confined to the posterior margin of the early wing bud and is associated with the polarizing region. In addition, we determined the distribution of Fgf-4 transcripts which in normal limb buds are restricted to the posterior part of the apical ectodermal ridge. In ta3 limb buds, shh expression is restricted to the posterior limb mesenchyme, which has high polarizing activity, but is not expressed in regions which have low polarizing activity. In contrast, Bmp-2 and Bmp-7 are expressed uniformly along the a-p axis. Fgf-4 transcripts are present throughout the apical ectodermal ridge in ta3 limb buds. In the ta3 mutant, there is both an abnormal distribution of signalling activity and response to polarizing signals. In addition, the dissociation between the expression of shh and Bmps suggests distinct roles for the encoded molecules in signalling and response in a-p patterning of limb buds.

Animals↗
PubMed1994

Second-line treatment with ifosfamide and carboplatin in patients with ovarian carcinoma relapsing after treatment with carboplatin.

20 patients with ovarian carcinoma whose disease had relapsed (1-42 months, median 4 months) after showing either response or stable disease to carboplatin, were treated with ifosfamide (5 g/m2 intravenously over 24 h, day 1) and carboplatin (200 mg/m2 intravenously day 2) as second-line treatment. The mean number of treatment cycles was 3.5 (range 1-6). The major toxicities were thrombocytopenia (WHO grade 3/4, 25%), neutropenia (WHO grade 3/4, 40%) and encephalopathy (WHO grade 3/4, 15%). Overall response rate was 15% [complete response, 0; partial response, 3 (15%); no change, 5 (25%) and progressive disease, 12 (60%)]. The median survival from the date of second-line treatment was 7 months. This combination offers no advantage over either agent used alone.

Adult↗
PubMed1994

Transgenic birds by DNA microinjection.

We have developed a method for production of transgenic chickens by DNA microinjection of chick zygotes followed by ex vivo embryo culture. The fate of plasmid DNA microinjected into the germinal disc of zygotes was analyzed in embryos which survived for at least 12 days in culture. Approximately half of the embryos contained plasmid DNA, 6% at a level equivalent to one copy per cell in all tissues analyzed. Seven chicks, 5.5% of the total number of injected ova, survived to sexual maturity. One of these, a cockerel, transmitted the exogenous DNA to 3.4% of his offspring. These G1 birds have reached sexual maturity and have been bred to produce transgenic offspring, demonstrating that stable transmission of foreign DNA can be obtained by our method.

Animals↗
PubMed1990

Low-dose CT of the lungs: preliminary observations.

The potential of low-dose computed tomography (CT) of the lungs was critically evaluated in two patients with normal-appearing lungs and 10 patients with a wide diversity of underlying parenchymal abnormalities. At each of five levels, in addition to routine scans obtained at 120 kVp and 140 mA, a scan at 10 mA and a half scan at 10 mA were obtained, with all other parameters held constant. Each scan was evaluated visually to assess anatomic clarity as well as the presence of artifacts and the extent of graininess. At all levels of the thorax, visualization of parenchymal structures was not affected by decreasing the milliamperage. It appears that high-quality, diagnostic images of the lung can be obtained with a very low radiation dose. Although further evaluation is necessary, the potential of low-dose CT for use in the pediatric population in particular, as well as for screening in patients at high risk for developing lung cancer, is apparent.

Humans↗
PubMed1979

In vivo methylation of bacteriophage phi X174 DNA.

A mutant (designated mec(-)) has been isolated from Escherichia coli C which has lost DNA-cytosine methylase activity and the ability to protect phage lambda against in vivo restriction by the RII endonuclease. This situation is analogous to that observed with an E. coli K-12 mec(-) mutant; thus, the E. coli C methylase appears to have overlapping sequence specificity with the K-12 and RII enzymes; (the latter methylases have been shown previously to recognize the same sequence). Covalently closed, supertwisted double-standed DNA (RFI) was isolated from C mec(+) and C mec(-) cells infected with bacteriophage phiX174. phiX. mec(-) RFI is sensitive to in vitro cleavage by R.EcoRII and is cut twice to produce two fragments of almost equal size. In contrast, phiX.mec(+) RFI is relatively resistant to in vitro cleavage by R.EcoRII. R.BstI, which cleaves mec(+)/RII sites independent of the presence or absence of 5-methylcytosine, cleaves both forms of the RFI and produces two fragments similar in size to those observed with R. EcoRII. These results demonstrate that phiX.mec(+) RFI is methylated in vivo by the host mec(+) enzyme and that this methylation protects the DNA against cleavage by R.EcoRII. This is consistent with the known location of two mec(+)/ RII sequences (viz., [Formula: see text]) on the phiX174 map. Mature singlestranded virion DNA was isolated from phiX174 propagated in C mec(+) or C mec(-) in the presence of l-[methyl-(3)H]methionine. Paper chromatographic analyses of acid hydrolysates revealed that phiX.mec(+) DNA had a 10-fold-higher ratio of [(3)H]5-methylcytosine to [(3)H]cytosine compared to phiX.mec(-). Since phiX.mec(+) contains, on the average, approximately 1 5-methylcytosine residue per viral DNA, we conclude that methylation of phiX174 is mediated by the host mec(+) enzyme only. These results are not consistent with the conclusions of previous reports that phiX174 methylation is mediated by a phage-induced enzyme and that methylation is essential for normal phage development.

Bacteriophage phi X 174↗