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Biomedical subjects

R Lowe

Publications and source records attributed to R Lowe.

At least 55 records · Page 3Linked to original sources
PubMed1985

Biologic fate of valves in reversed and nonreversed arterial vein grafts.

The cusps of valve-bearing segments of canine cephalic, femoral, and jugular veins were completely divided and were used in interposition grafts in the femoral and carotid arteries in the nonreversed position. Three control grafts had intact valves in the reversed position, and one control graft in the reversed position had division of the leaflets. Nine grafts were studied up to 2 months postoperatively with gross and microscopic observations. The cusp tissue, which shrinks immediately after complete division, disappears very early in the postoperative period in the reversed and nonreversed positions. Two reversed intact valves were still grossly microscopically normal 5 and 7 weeks postoperatively. The complete disappearance of the divided valve with a nonreversed coronary graft 101/2 months postoperatively has been documented at autopsy for the first time in a human subject. The significance of these findings and the superiority of the valveless nonreversed autogenous vein graft in clinical cardiovascular surgery has been discussed.

Animals↗
PubMed1985

Development and analysis of a transformation-defective mutant of Harvey murine sarcoma tk virus and its gene product.

The Harvey murine sarcoma virus has been cloned and induces focus formation on NIH 3T3 cells. Recombinants of this virus have been constructed which include the thymidine kinase gene of herpes simplex virus type 1 in a downstream linkage with the p21 ras gene of Harvey murine sarcoma virus. Harvey murine sarcoma tk virus rescued from cells transfected with this construct is both thymidine kinase positive and focus inducing in in vitro transmission studies. The hypoxanthine-aminopterin-thymidine selectability of the thymidine kinase gene carried by this virus has been exploited to develop three mutants defective in the p21 ras sequence. All three are focus negative and thymidine kinase positive when transmitted to suitable cells. Of these, only one encodes a p22 that is immunologically related to p21. This mutant has been used to explore the relationship between the known characteristics of p21 and cellular transformation. Data presented herein indicate that the p21 of Harvey murine sarcoma virus consists of at least two domains, one which specifies the guanine nucleotide-binding activity of p21 and the other which is involved in p21-membrane association in transformed cells.

Animals↗
PubMed1984

Early treatment of streptococcal pharyngitis.

The concept of treating presumed streptococcal pharyngitis prior to obtaining throat culture results remains controversial. We review the rationale for early treatment and the predictive ability of current techniques for rapidly estimating the probability of streptococcal pharyngitis. Decision analysis is combined with clinical and microscopic predictive tests to provide an approach for early treatment of presumed streptococcal pharyngitis. Our unified approach supports the treatment of presumed streptococcal pharyngitis prior to obtaining culture results when specific clinical or microscopic criteria are met.

Adolescent↗
PubMed1982

A bullet in the appendix.

An unusual case of a foreign body lodged in the appendix after traumatic intestinal penetration is described. Although rarely found, foreign bodies in the appendix may produce acute appendicitis and other complications which necessitate surgery. An appendectomy is recommended: 1) for all symptomatic patients; 2) in patients with pointed objects retained because such patients are at potential risk for perforation; or 3) in any patient with a foreign body in the appendix who is undergoing intra-abdominal surgery for other reasons.

Adult↗
PubMed1981

Role of the Lombard effect in lingual vibrotactile thresholds.

Lingual sensory, auditory, and vocal intensity interactions were investigated for 20 subjects. Lingual vibrotactile measurements were obtained from the lingual dorsum after normal reading, reading during exposure to auditory masking producing the "Lombard effect," and reading with matched Lombard loudness with no auditory masking. Results do not demonstrate a significant shift in threshold for lingual sensitivity in the presence of auditory masking that previous studies have shown. The observed results are discussed with reference to possible physiological properties and experimental and procedural variables.

Acoustic Stimulation↗
PubMed1980

Subgenomic fragment of molecular cloned Friend murine leukemia virus DNA contains the gene(s) responsible for Friend murine leukemia virus-induced disease.

Friend murine leukemia virus (G-MuLV) is a helper-independent, type C retrovirus isolated from stocks of Friend virus complex (spleen focus-forming virus plus MuLV). In cell culture, F-MuLV has an ecotropic and NB-tropic host range and causes XC cells to fuse. When injected into newborn NIH Swiss mice, F-MuLV produces hepatosplenomegaly, severe anemia, and numerous circulating hematopoietic precursors in the peripheral blood with normal thymus and lymph nodes after 3 to 6 weeks. Recently, we molecularly cloned an 8.5-kilobase pair (kbp) form of F-MuLV DNA from which we could recover the pathogenic F-MuLV virus by DNA transfection of NIH 3T3 cells. From this molecularly cloned F-MuLV DNA, we have now subcloned in pBR322 a 4.1-kbp HindIII fragment which contains in continuity 3.0 kbp from the 3' terminus (env and c region), 0.6 kbp of the terminal repeat sequences, and 0.5 kbp from the 5'terminus of the viral RNA (genome). NIH 3T3 fibroblasts were transfected with this DNA fragment an then infected with the wild mouse amphotropic retrovirus (cl 1504-A). In cell culture, 1504-A is a helper-independent type C virus which has an N-tropic host range and does not cause fusion of XC cells. When injected into newborn NIH Swiss mice, 1504-A does not produce splenomegaly or thymic enlargement in mice held for up to 8 months. The transfection with the F-MuLV fragment and the infection with 1504-A consistently yielded virus preparations that were XC positive. From such virus stocks we were able to isolate both helper-independent and replication-defective XC-positive viruses. The helper-independent virus was shown to be a recombinant virus since it contains a gp70 molecule derived at least in part from F-MuLV and a specific gag precursor derived from 1504-A as determined by radioactive immune precipitation assays. When injected into newborn Swiss mice, the recombinant helper-independent virus caused hepatosplenomegaly in approximately 50% of the mice in 6 to 8 weeks. The histology of the diseased splenic tissue was indistinguishable from that seen in the disease caused by the whole F-MuLV. The replication-defective virus could be pseudotyped with new 1504-A virus, and this viral complex also caused the F-MuLV disease picture when the complex was injected into newborn Swiss mice. We conclude that the genetic information responsible for the pathogenicity of F-MuLV is contained within the 4.1-kbp DNA fragment, which includes env gene sequences, the terminal repeat sequences, and the c region sequences of the F-MuLV genome.

Animals↗