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Biomedical subjects

M Carlson

Publications and source records attributed to M Carlson.

At least 253 records · Page 14Linked to original sources

High-dose methotrexate as secondary chemotherapy in metastatic soft-tissue sarcomas.

High-dose methotrexate in a dose of 2-4 g/m2 every four weeks was given as secondary chemotherapy to 22 patients with metastatic soft-tissue sarcoma; toxic reactions included 1 death and 2 instances of moderate hematopoietic toxicity. The remaining patients tolerated this treatment without difficulty. Of 18 patients with measurable evaluable disease, 17 demonstrated progression. One patient with metastatic angiosarcoma had a complete response lasting for 15 months. Three patients were given adjuvant high-dose methotrexate following wedge resections of pulmonary metastases. One patient demonstrated recurrence after four months, another after 13 months, and the third after 15 months. One additional patient underwent resection of pulmonary metastases following two months of stabilization with high-dose methotrexate and has continued free of disease with high-dose methotrexate as adjuvant for eight months. Five patients are alive and have been disease-free for an average period of 14 months. Four of these underwent operative treatment combined with chemotherapy. The effectiveness of high-dose methotrexate appears limited in soft-tissue sarcomas when it is given as secondary chemotherapy.

Adolescent↗

Somatic sensory cortex (SmI) of the prosimian primate Galago crassicaudatus: organization of mechanoreceptive input from the hand in relation to cytoarchitecture.

Mechanoreceptive input from the hand to the somatic sensory cortex (SmI) of the prosimian primate Galago crassicaudatus was examined with microelectrode mapping methods. In anesthetized animals, low threshold cutaneous input from the hand projects to SmI cortex in a single, complete, somatotopically organized pattern. Within this single pattern, cells with receptive fields on the glabrous skin of the palm, digits and digit tips are located in the rostral half, and cells with RFs on the hairy skin of the dorsal hand and digits are located in the caudal half of the hand areas. The cutaneous hand area is coextensive with the densely granular architectonic region of SmI. Studies of single cells in this region of awake galagos reveal the same pattern of cutaneous input and, in addition, demonstrate the presence of cells responding to joint movement not detected in anesthetized animals. Cells responsive to joint movement are arranged in vertically oriented columns located adjacent to cutaneous columns with receptive fields on the same part of the hand. In anesthetized animals, cells rostral to the granular region, in an area typified by increasing numbers of pyramidal cells in layer V and decreasing numbers of granular cells in upper layers, respond to high threshold stimulation of large areas of the hand. The few cells isolated in this area in awake animals respond to either active or passive hand movements. In such animals, cells caudal to the granular region, in an area characterized as agranular and alaminar cortex, respond to either passive stimulation of single or multiple joints or to active hand movements. These results, together with similar findings in a related prosimian, Nycticebus coucang, emphasize the generality of a single cutaneous hand area in SmI of prosimian species. The demonstration of multiple hand areas corresponding to multiple cytoarchitectonic subdivisions in SmI of Old and New World simians illustrates the increased degree of SmI differentiation from the prosimian to the simian grade of organization. The present results further suggest that determination of the homologues of multiple areas or subdivisions within and surrounding SmI in primates will require comparisons of somatotopy, submodality, sulcal patterns, cytoarchitecture, and connectivity in representative members of prosimian and simian families.

Anesthesia, General↗

Polarographic determination of edetate disodium in eyewash and ophthalmic decongestant solutions.

The quantitative analysis of edetate disodium in nonprescription eyewash and ophthalmic solutions is described. The method involves differential pulse polarography using a dropping mercury electrode. A known concentration of cadmium or zinc is added to a buffer in a polarographic cell. The sample solution is incremented into the cell with a micropipet. The peak current decreases because the resulting chelate is not reducible at the potentials used. The quantity of edetate disodium in the sample then is determined graphically. Some contact lens cleaning and wetting solutions containing polymeric compounds are amenable to assay to edetate disodium if extraction, precipitation, centrifugation, or dilution steps minimize the maximum suppressor effect of the additives. These steps are very effective with cellulose ether compounds but are ineffective with polyvinyl alcohol.

Edetic Acid↗

High-dose methotrexate in malignant melanoma.

High-dose methotrexate was given to 28 patients with advanced malignant melanoma who had previously failed to respond to two chemotherapy protocols. There were five instances of serious, but not fatal, toxicity. One patient has had an objective response and seven patients have had stabilization of disease with an average duration of 4 months.

Adult↗

One of the copia genes is adjacent to satellite DNA in Drosophila melanogaster.

A method for purifying sequences adjacent to satellite DNA in the heterochromatin of D. melanogaster is described. A cloned DNA segment containing part of a copia gene adjacent to 1.688 g/cm3 satellite DNA has been isolated. The copia genes compose a repeated gene family which codes for abundant cytoplasmic poly(a)-containing RNA (Young and Hogness, 1977; Finnegan et al., 1978). We have identified two major poly (A)-containing RNA species [5.2 and 2.1 kilobases (kb)] produced by the copia gene family. The cloned segment contains copia sequences homologous to the 5' end of RNA within 0.65 kb of the 1.688 satellite DNA sequences. Seven different cloned copia genes from elsewhere in the genome have also been isolated, and a 5.2 kb region present in five of the clones was identified as copia by heteroduplex analysis. In addition, three ususual copies of copia were found: a "partial" copy of the gene (3.7 kb) which has one endpoint in common with the 5.2 kb unit; a copia gene flanked on one side by a 1.6 kb sequence and on the other by the same 1.6 kb sequence in the inverted orientation; and a copia gene flanked only on one side by the same sequence.

Animals↗

A gene adjacent to satellite DNA in Drosophila melanogaster.

Several copies of a sequence adjacent to 1.688 g/cm3 satellite DNA in the Drosophila melanogaster genome have been isolated by molecular cloning. This sequence, called the Dm142 gene, is homologous to a 1.6-kilobase RNA found in both D. melanogaster embryos and tissue culture cells. One cloned DNA segment includes two copies of the Dm142 gene and 1.688 g/cm3 satellite DNA sequences, which are located between and flanking both gene copies. The Dm142 gene is repeated many times in the D. melanogaster genome, and some copies are not flanked by 1,688 g/cm3 satellite DNA.

Alleles↗

Adjustable rectus muscle recession surgery. A follow-up study.

Fifty-six patients underwent an adjustable rectus muscle recession procedure. This procedure permits the surgeon to enhance or diminish the amount of muscle recession on the evening after surgery or the first postoperative day if cover-testing indicates an inappropriate amount of undercorrection or overcorrection. The adjustable rectus muscle recession technique seems to be a practical and effective means to change the strabismic deviation postoperatively. The procedure requires patient cooperation and is most suitable for patients age 15 years and older. The procedure has been effective in altering the angle of deviation, and this alteration has been stable during the follow-up period in most cases. In this initial series, the reoperation rate was low, postoperative alignment was excellent, and complications were minimal.

Adolescent↗

Somatic sensory cortex of hyrax (Procavia).

Somatic sensory (SI) cortex was mapped in hyraxes by micromapping methods developed and used earlier in slow lorises and llamas. The somatotopic pattern of organization was similar in its general features to that found in other mammals. The perioral and intraoral representations are relatively large in SI of hyrax and exhibit considerable distortion. Sulci are reliable landmarks demarcating boundaries of SI in hyrax as they are in other mammals.

Animals↗

Some morphological, physiological and behavioral specializations in North American beavers (Castor canadensis).

In order to gain insight into the functional properties of the tail in North American beavers (Castor canadensis) we (1) examined morphological features of skeletal, muscular, vascular, cutaneous and neural structures; (2) determined the segmental organization of spinal roots and certain stimulus-response features of receptive fields of single dorsal root fibers; (3) mapped the main somatic sensory area (SI) of the cerebral neocortex, and (4) attempted to relate these findings to observations of tail behavior in living beavers. The behavioral observations revealed the beaver capable of forceful yet discrete movements of the tail in water. A morphological correlate of these motor skills was the distinct segmentally organized pattern of serial muscle tendon arrangements and spinal sensory and motor innervation. Neither the receptors innervating the scales or hairs of the tail, the stimulus-response properties of single dorsal root afferents, nor the representation of the tail in SI suggested unusual cutaneous sensory capabilities associated with the morphological and behavioral specializations exhibited by the beaver's tail.

Animals↗

Pathogenesis of aphakic macular edema.

Six months after cataract extraction, a 71-year-old man had cystoid macular edema confirmed by fluorescein angiography. Microscopic examination revealed cystoid spaces in the outer plexiform and outer nuclear layer of the neurosensory retina. Chronic inflammatory cells were scattered throughout the ciliary body. Inflammatory cells were also present in a section of iris that had an adherent strand of vitreous leading to the pars plana. Comparison of these findings with other related clinical entities supported the hypothesis that ciliary body inflammation may play a significant role in postcataract extraction macular edema.

Aged↗