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Biomedical subjects

D L Larson

Publications and source records attributed to D L Larson.

At least 145 records · Page 8Linked to original sources
PubMed1976

Laryngeal injury: a critical review.

Thirty consecutive cases of laryngeal trauma requiring open exploration are reviewed. Eighteen injuries were the result of blunt trauma and 12 resulted from penetrating wounds. Within the blunt trauma group, eight of 18 injuries resulted in a competent airway and a good voice, six with a good airway but a fair voice, and four with airway compromise. Of 12 patients with penetrating wounds, ten sustained a good airway and a good voice, two a good airway and fair voice. Substantial granulation tissue response, though occurring in only eight of the 30 patients, was present in three of the four patients with airway stenosis. The use of a stent, in association with a soft tissue graft when mucosal loss cannot be approximated primarily, does not predispose to such a response, but rather facillitates maintenance of a competent skeletal framework and prevention of soft tissue endolaryngeal distortion.

Adolescent↗
PubMed1976

Relationship between analgetic ED50 dose and time-course brain levels N-alkylnormeperidine homologues.

The brain levels of meperidine and three N-alkyl homologues were determined at equal analgetic iv doses in mice. The relative levels of the four compounds in brain were found to be closely proportional to their ED50 doses even though the compounds exhibit a wide range in partition coefficient and metabolic N-dealkylation. While lipid solubility and metabolism are undoubtedly important factors in the overall time-course brain levels, it appears that during the period of analgetic measurement (5-60 min after injection) these factors do not profoundly affect the relative brain levels because peak uptake occurs within the first 5 min after administration of the homologues. As a consequence, the observed ED50 potencies appear to provide a fair approximation of the relative receptor affinities of the four homologues. N-Dealkylation was observed as a major metabolic transformation by mouse liver in vivo for all four compounds, and the extent of this N-dealkylation was found to directly correspond to the rates of N-dealkylation by mouse liver homogenate seen in an earlier study.

Analgesics↗
PubMed1976

Management of acute laryngeal injury: a critical review.

The approach to management of 30 cases of laryngeal trauma coming to open exploration is outlined. Eighteen patients had blunt trauma and 12 had penetrating wounds. Four cases resulted in airway compromise and all were in the blunt trauma group. Although significant granulation tissue response occurred in only eight of 30 cases, it was present in three of the four concluding with stenosis. It is demonstrated that the use of a stent, with a tissue graft, when mucosal approximation cannot be accomplished, facilitates prevention of endolaryngeal distortion and webbing and maintenance of skeletal framework integrity; its use did not predispose to granulation tissue development. A principal etiologic factor in those patients who had good airway but only a fair voice was arytenoid fixation, this despite anatomic reduction when subluxation occurred. Recurrent nerve injury was identified in only one patient. Foremost in management is suspicion and recognition of laryngeal injury in the multiple trauma patient. Once the urgent problems of hemorrhage, shock, and airway are attended to, attention must be directed to a systematic evaluation of the neck and larynx.

Airway Obstruction↗
PubMed1976

Thumb reconstruction in the severely burned hand.

The standard techniques have generally been adequate for thumb reconstruction in the severely burned hand. The basic principles of preservation of length, prevention of malposition and contracture by appropriate splinting, early motion, and early skin coverage are all applicable. The nature of the tissue changes wrought by the burn wound, however, frequently necessitates certain modifications in the approach to surgical reconstruction. We have described these and our methods used in handling 9 specific cases.

Adolescent↗
PubMed1976

Reconstruction of eyelids and eyebrows in burned patients.

The records of 283 consecutive patients treated for facial burns were reviewed. Eighteen percent of these patients had significant deformities of the eyelids or adnexal structures and underwent surgical correction. Our experience in managing these patients is presented and discussed.

Adult↗
PubMed1976

Detection of simian type-C particles in Mason-Pfizer virus infected cultures.

A simian type-C virus has been detected in cultures chronically infected with Mason-Pfizer monkey virus (M-PMV). Simultaneous budding of M-PMV and type-C virus particles from the same cells was observed in cultures incubated at 37 or 40 degrees C. However, the frequency of such cells was greater in cultures grown at 40 degrees C. Although clusters of type-C viral buds were seen at the surface of the cells, extracellular mature type-C particles in cell pellets or concentrated virus preparations were very rarely found. The increase in frequency of type-C buds was found to be transitory since cultures adapted to growing at the high temperature demonstrated budding type-C particles only occasionally. Cultures producing type-C buds were found to contain, in addition to M-PMV antigens, serological activity with polyvalent antisera produced against multiple structural components of endogenous baboon virus (BV) or simian sarcoma virus (SiSV). The reactivity, however, was found not to be serologically related to the major SiSV P28 core protein.

Animals↗
PubMed1976

Practical considerations in the development of a human cancer vaccine.

Factors involved in the development of a human oncornavirus vaccine are discussed. The isolation and purification of subviral gp69/71 antigenic components enhance the feasibility of developing safe vaccine. The recent isolation of a C-type virus (the HL-23) from a human leukemic patient and its similarity to the simian sarcoma virus presents us with a unique opportunity to test the safety and potency of a vaccine in nonhuman primates.

Animals↗
PubMed1976

Liposarcoma of the tongue.

Liposarcoma is a rare tumor in the head and neck. No previous report of its occurrence in the tongue is found at the time of this writing and this prompts its presentation. Significant in its management is wide surgical excision. Irradiation may be effective in some metastases. Prognosis is best in well differentiated forms.

Adult↗
PubMed1975

Interactions between endogenous baboon type-C virus and oncogenic viruses. I. Syncytium induction and development of infectivity assay.

Cells releasing the endogenous baboon virus (BV) can interact with human KC cells containing the Rous sarcoma virus (RSV) genome, resulting in cell fusion and syncytium formation. This interaction has been utilized in the development of a sensitive infectivity assay for BV. The titration pattern is of a one-hit type, demonstrating a linear relationship between virus concentration and number of syncytial plaques obtained in the KC co-cultivation assay. Endpoint titration comparisons indicate that the KC test is as sensitive as the immunofluorescence or the RNA-directed DNA-polymerase assays. Attempts to develop an XC test for BV failed, indicating that while BV can interact with the RSV genome it will do so in the human KC cells and not in the rat XC cells. Syncytia are also induced when KC cells are directly exposed to cell-free BV; however, a linear dose relationship is not obtained. When syncytium-positive KC cultures are passaged, the syncytia disappear and a chronic BV infection is established. These KC-BV cells then lose the ability to interact with either the endogenous cat RD-114 virus or the Mason-Pfizer virus which are known to form syncytia with KC cells.

Animals↗
PubMed1975

B-lymphocytosis factor in human plasma.

Patients with acute thermal burns experience an increase of serum immunoglobulins associated with marked B-lymphocytosis during the recovery phase from the burn injury. This study was performed to delineate humoral factors which may induce the B-lymphocytosis in such patients. Plasma samples were obtained serially from 14 adult patients and 14 adult controls. One-half ml of plasma was injected intraperitoneally into C3H/He male mice, and absolute numbers of surface immunoglobulin-bearing cells in the mouse peripheral blood were counted. Fractionation of plasma samples was performed. The biologically active plasma fraction, tentatively termed B-lymphocytosis factor (BLF), was cultured with normal human peripheral blood lymphocytes to determine in vitro lymphocyte transformation. The solubility of 125I-labelled BLF in various organic solvents was examined. Plasma obtained from burned patients induced a marked increase of IgG, IgA, and IgM-bearing cells in the peripheral blood of mice within 3 hours after injection. The B-lymphocytosis activity of normal plasma was not significant. The molecular weight of BLF was estimated to be close to that of ribonuclease A (M.W. 13,400). Transformation of normal human peripheral blood lymphocytes was observed when cultured with BLF. 125I-labelled BLF was not soluble in organic solvents. These data suggest that BLF is not a lipopolysaccharide, and plays a role in regulation of B-lymphocyte levels in burned patients.

Adolescent↗
PubMed1975

Prevention and management of contractures in patients with burns of the neck.

Two hundred patients with neck burns were analyzed to determine the incidence of contractures. It was found that only 8 per cent of patients with second degree burns had contractures, all of which were mild. Both the overall incidence of cervical contractures in patients with third degree neck burns and their severity can be decreased by the use of a custom-formed isoprene splint. Splinting should begin as soon as possible after the burn and continue until scar maturation is complete.

Burns↗
PubMed1975

Burned hands.

Hand involvement is common in patients with severe burns. Our experience indicates that almost one-third of the patients admitted to the Shriner's Burns Institute and The University of Texas Medical Branch Hospitals with burns exceeding 30 per cent of the body surface had concomitant burns of the hand. Our approach in managing the burned hand during the acute phase of unjury, as well as during secondary reconstruction of the deformities, is presented and discussed.

Burns↗
PubMed1975

The observation of myofibroblasts in hypertrophic scars.

Contractile fibroblasts, myofibroblasts, are common cellular components of immature human hypertrophic scars. The contraction of these cells, could play a significant role in the elevation of the scar tissue. The appearance of such cells within granulation tissue suggests that the tissue is pre-disposed to hypertrophy at an early stage of repair.

Biopsy↗