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B Forbes

Publications and source records attributed to B Forbes.

29 records · Page 2Linked to original sources
PubMed1994

Adenovirus vector-mediated in vivo gene transfer into adult murine retina.

PURPOSE: To determine whether a reporter gene can be introduced into the adult mammalian retina in vivo through means of a recombinant replication-deficient adenovirus. METHODS: A dilution series of purified Ad.CMVlacZ ranging from 10(5) to 10(11) pfu/ml was prepared and microinjected into the subretinal space of adult CD-1 mice. This virus contained the cytomegalovirus (CMV)-promoted Escherichia coli reporter gene, lacZ. LacZ expression was assessed in enucleated eyes from 0 to 95 days after injection by beta-galactosidase (beta-Gal) assay. RESULTS: The efficiency of transfection increased as a function of concentration of recombinant virus injected. Eyes injected with greater than 10(7) pfu of Ad.CMVlacZ demonstrated beta-Gal activity lasting at least 95 days. LacZ expression was apparent only in those cells directly exposed to the adenovirus. LacZ expression was observed in the retinal pigment epithelium (RPE) at high efficiency at 48 hours after exposure. By 2 weeks after injection of > 10(7) pfu, lacZ was also expressed in photoreceptors, but at lower density. CONCLUSIONS: These results demonstrate that high efficiency stable transfer of functional genes can be achieved in vivo in post-mitotic mammalian retina using recombinant adenoviral vectors. Adenovirus vectors appear to be a promising means for delivering therapeutic genes in vivo to the mammalian neural retina and particularly to the RPE.

Adenoviruses, Human↗
PubMed1993

Dynamics of central venous catheter-related sepsis in rats.

To determine when catheter-related sepsis clears after removal of an infected central venous catheter (CVC) and when a new sterile CVC can be inserted without risk of recolonization, a catheter infected with 10(5) CFU of Staphylococcus epidermidis per ml was inserted into 40 Fischer 344 rats. Five control rats had sterile catheters. Insertion of an infected CVC was followed by a significant rise in leukocytes after 4 days and the presence of S. epidermidis in lungs, livers, spleens, kidneys, and the catheter tip, as examined by bacteriological assay. After the infected catheter was removed, the rat recovered from the induced catheter-related sepsis within 12 h. When a new sterile CVC was inserted into the femoral vein, the leukocyte count remained normal, and all catheter tips and tissue cultures were sterile 4 days later.

Animals↗
PubMed1990

An insulin-like growth factor-binding protein purified from medium conditioned by a human lung fibroblast cell line (He[39]L) has a novel N-terminal sequence.

We have identified a novel insulin-like growth factor (IGF)-binding protein secreted into the culture medium of a human lung fibroblast cell line (He[39]L). This binding protein was purified by S-Sepharose cation exchange chromatography, IGF affinity chromatography and reverse-phase high-performance liquid chromatography. Analysis of the He[39]L-binding protein on silver-stained polyacrylamide gels and by ligand blotting showed that it had a molecular weight of 32 kDa under non-reducing conditions. In charcoal competition binding assays, IGF-II competed at lower concentrations than IGF-I for binding to the He[39]L-binding protein and the more potent form of IGF-I (des-(1-3)-IGF-I) was not bound. This is a similar IGF binding pattern to that of the bovine IGF-binding protein-2 (bIGFBP-2). However, immunoblotting with an antibody to bIGFBP-2 demonstrated that the He[39]L-binding protein is not immunochemically related to bIGFBP-2. It is a glycosylated protein, having N-acetyl-glucosaminyl sugars detected by wheatgerm agglutinin affinity chromatography. Of the first 15 N-terminal amino acids of the He[39]L-binding protein, 13 are identical to the 15 amino acid sequence of a recently sequenced cerebrospinal fluid-binding protein. However, the total He[39]L-binding protein sequence (25 amino acids) showed no homology to other previously sequenced binding proteins (IGFBP-1, IGFBP-2 and IGFBP-3). We conclude that the He[39]L-binding protein is a novel binding protein.

Amino Acid Sequence↗
PubMed1988

Classification of the insulin-like growth factor binding proteins into three distinct categories according to their binding specificities.

Competitive binding experiments with insulin-like growth factor (IGF)-1, IGF-2 and des-(1-3)-IGF-1 have confirmed the interpretation based on limited amino-terminal sequence analysis that at least three types of IGF binding protein occur. In addition to the acid stable subunit of the large serum binding protein which exhibits des-(1-3)-IGF-1 binding only slightly less than IGF-1, the small IGF binding proteins can be separated into two classes based on differences in des-(1-3)-IGF-1 and IGF-2 binding potencies.

Animals↗
PubMed1988

Detection of individual virus-infected cells by filter in situ hybridization.

The diagnosis of virus infection by nucleic acid hybridization represents an alternative to classical virological diagnostic methods. One special technique termed 'filter in situ hybridization' consists of fixation of intact cells to nitrocellulose filters followed by hybridization with a labelled DNA probe. We demonstrate that filter in situ hybridization can be a simple and sensitive method for the detection of virus infection in cells. In an in vitro model system using a human B-lymphoma cell line infected by the lymphotropic papovavirus (LPV), it is shown that individual virus replicating cells can be detected by this method. Infection can be diagnosed even if only one out of 20,000 cells in a culture contains replicating virus. This assay may be of value as a diagnostic tool in other viral systems.

Cell Line↗
PubMed1987

Sodium and bicarbonate fluxes in regenerating rabbit corneal endothelium.

Rabbit corneal endothelia were subjected to a cryoinjury (-70 degrees C for 15 sec) and sodium and bicarbonate fluxes were determined at various times after induction of the endothelial destruction. A complete monolayer of cells was present by 4 days that consisted of large cells that underwent division over the next 16 days. Unidirectional sodium fluxes were unaltered by the transformation from large to normal sized hexagonal cells. Unidirectional bicarbonate fluxes showed an increase in Jendostr coupled with a decrease in the net Jstrendo flux. As the cells became smaller these bicarbonate fluxes returned to normal values. The data indicate that the cell margin/cell size ratio is not related to the flux rates, thus the paracellular pathway increase with healing is not related to the passage of either sodium or bicarbonate. Secondly, the data indicate separate effects on both sodium and bicarbonate, suggesting that transendothelial movement of the ions can be separated and that they are not necessarily linked in passage across the endothelium.

Animals↗
PubMed1987

The benefits of Isolator cultures in the management of suspected catheter sepsis.

Until recently, when a patient receiving total parenteral nutrition (TPN) was suspected of having catheter-related sepsis, the catheter was removed and the tip and the patient's blood was cultured. Using this method at our institution, greater than two thirds of the central venous catheters (CVC) removed were sterile, or if colonized, proved not to be the source of sepsis. This practice led to the unwarranted removal of numerous catheters and posed a clinical dilemma because it necessitated replacement of the catheter with its attendant risks, cost, and inconvenience. To address this problem, we instituted a protocol for determining in situ catheter-related sepsis based on a quantitative blood culture method using lysis centrifugation (Isolator; Dupont Co., Wilmington, Del.). When catheter-related sepsis was clinically suspected, quantitative blood cultures were obtained simultaneously via a peripheral (PER) vein and through the CVC suspected as the source of sepsis. The CVC, however, remained in situ pending culture results (approximately 16 to 24 hours). A CVC colony of greater than or equal to five times the PER colony count was considered significant and the catheter was removed. Equivocal colony counts between the CVC and PER cultures were interpreted as incriminating a source of sepsis other than the CVC. An 8-month prospective study was undertaken to evaluate the efficacy of this method for determining in situ catheter sepsis. One hundred third-eight patients received TPN by means of 160 catheters. In 113 patients no sepsis-related problems were noted. In the remaining 25 patients, 28 catheters were suspected as the source of sepsis. Twenty-six catheters were evaluated by the Isolator culture method. In eight instances significant differences in colony counts between the CVC and PER cultures were seen, implicating the CVC as the source of infection. In all these cases the CVC was removed and the patients underwent defervescence. In 18 cases, the CVC samples revealed either no growth or insignificant differences between the CVC and PER colony counts. Nine of these CVCs were removed without clinical improvement. The remaining nine catheters were left in place, and another source of sepsis was ultimately identified and treated. These results confirm the use of the quantitative blood culture method for determining in situ catheter-related sepsis. In all cases, when the catheter was incriminated by culture data, removal of the CVC led to patient improvement.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMedDate not supplied

Bacteriological safety of closed enteral nutrition delivery system.

One of the most commonly reported side effects of enteral tube feedings is diarrhea, at times attributed to the bacterial contamination of tube feedings. A closed enteral delivery system has recently been devised. It consists of a cardboard Tetrapack containing the sterile enteral nutrition formula and and independent sterile administration set; together these constitute a closed Tetrapack-administration set enteral delivery system. The bacteriological safety of this system was evaluated in vitro under controlled laboratory conditions in a series of studies. There was no or bacteriologically insignificant bacterial contamination of the enteral nutrition formula, even with repeated use of one administration set for multiple containers over 24 h. Bacteriological growth in the enteral nutrition formula was directly related to the duration of the hanging time of a Tetrapack container. No bacterial growth occurred with hanging times less than 18 h; insignificant bacterial growth occurred by 24 h. A progressive time-related increase in bacterial growth occurred between 24 and 48 h. Our data indicate that the newly developed closed Tetrapack-administration set enteral delivery system is, and will remain, bacteriologically sterile if each Tetrapack container is allowed to hang for no longer than 24 h.

Bacteria↗
PubMedDate not supplied

[The bacteriological diagnosis of catheter-related sepsis. The advantages of quantitative blood cultures].

If sepsis due to a catheter is suspected in a patient receiving parenteral nutrition, the doctor responsible for the patient usually withdraws the catheter and sends the point to the bacteriological laboratory for examination. This operation is usually accompanied by the extraction of several blood samples for haemoculture. With this attitude, it has been observed that most of the catheters withdrawn are sterile or if they are contaminated, they are not the cause of the sepsis. This leads to a series of unnecessary expenses and risks. This problem has prompted us to design a clinical study for the prospective investigation of the efficiency of quantitative haemocultures in the diagnosis of sepsis due to the catheter. During an 8-month period, all the patients who received parenteral nutrition in our centre were followed up by members of the nutritional support unit and participated in the study. In the face of the clinical suspicion of sepsis due to the catheter, blood was obtained for haemoculture, both through the catheter and from the peripheral veins. However, the catheters were not withdrawn until after the results of the cultures, between 16 and 24 hours following the extraction. A count of colonies in blood proceeding from the catheter which was five times or more greater than the count in the peripheral blood was interpreted as sepsis due to the catheter and the catheter was withdrawn. Differences between both counts (central and peripheral) which were less were interpreted as sepsis with a different origin to the catheter and in this case, the catheter was not withdrawn. A total of 26 catheters were evaluated using this method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗