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Biomedical subjects

M T Smith

Publications and source records attributed to M T Smith.

At least 307 records · Page 17Linked to original sources
PubMed1979

Anaplastic astrocytoma following radiation for a glomus jugular tumor.

Evaluation of radiation therapy for a given neoplasm includes consideration of possible treatment complications as well as potential benefit. A 43-year-old male with a glomus jugular tumor or the right middle ear had received 4480 rad to the right middle and inner ear and temporal bone. Eight years later, he developed an anaplastic astrocytoma of the right cerebellar hemisphere. At this time a third neoplasm, a left carotid body tumor, was demonstrated angiographically. Although radiation can be implicated in the genesis of the glial neoplasm, the presence of two neural crest derived tumors suggests that a lowered threshold for neoplastic transformation in neuroectodermal cells may have been an additional factor. Long-term follow-up of large numbers of patients with glomus jugulare tumors will be necessary to determine if multiple paragangliomas predispose to radiation-associated gliomas.

Adult↗
PubMed1979

Rhabdomyosarcoma arising in a pineal teratoma.

Pineal teratomas are relatively uncommon intracranial neoplasms. A rhabdomyosarcoma developed in a pineal teratoma in a 14-year-old boy and was rapidly fatal despite radiation therapy. This is the second reported case of a pineal teratoma giving rise to a rhabdomyosarcoma.

Adolescent↗
PubMed1979

Behavioral effects of strong 60-Hz electric fields in rats.

Eight individually housed male Long Evans rats were raised, beginning at age 30 days, for six weeks in an electric field exposure apparatus. During five of the six weeks, the animals were exposed to a 25 kV/m, 60-Hz electric field. A similar population of rats housed in an identical environment, except for the absence of the high voltage field, were used as control animals. Differences between the two groups in body mass, food and water intake, and exploratory activity were studied. Statistical analysis shows the high voltage fields to have no significant effects on the above parameters.

Animals↗
PubMed1979

Diagnosis of toxoplasmosis by electron microscopic fine-structural analysis.

The analysis of fine structures by electron microscopic examination of ultrathin tissue sections permitted a diagnosis of toxoplasmosis in a fatal human case that would have gone undiagnosed by conventional methods. Examination of histologically prepared sections revealed organisms that were morphologically nondiagnostic. Fine-structural analysis showed the organisms to be 3 x 2 micrometer in size, to contain few micronemes, to contain as many as nine rhoptries, to possess an apical conoid, and to multiply by endodyogeny. The features corresponded to those observed in fine-structural analyses of Toxoplasma gondii grown in animals by Scholtyseck and Mehlhorn. Fine-structural analysis can be a valuable adjunct in the diagnosis of toxoplasmosis.

Cell Division↗
PubMed1978

Systematics of Hanseniaspora Zikes and Kloeckera Janke.

The physiological and morphological characteristics of eighty-two strains of Hanseniaspora and Kloeckera, represented twenty-nine described species, were examined. These results along with DNA base composition and DNA/DNA reassociation experiments revealed that the genus Hanseniaspora comprises six distinct species, viz. H. valbyensis, H. uvarum, H. guilliermondii, H. occidentalis, H. osmophila and H. vineae, with K. japonica, K. apiculata, K. apis, K. javanica, K. corticis and K. africana, respectively, as their imperfect states.

Ascomycota↗
PubMed1978

Experimental dysraphism in the rat.

An experimental treatment that results in dysraphic lesions in rat embryos was studied to gain insight into the origin of such lesions. Pregnant rats given 100,000 units of vitamin A by gavage tube on gestational Days 8, 9, and 10 produced abnormal litters, and 50% of the embryos had exencephaly and/or spina bifida. Study of these embryonic lesions revealed hyperplesia of neural tube tissue that extended laterally to the edge of an epidermal defect. The epidermal defect consisted of the absence of fetal epidermis over the hyperplastic neural tissue. At no stage in development was embryonic hydrocephalus noted. In fact, the central canals of the embryos with malformations were poorly developed and smaller than those of control embryos. Results with this model indicate that the malformations arise through a process of overgrowth and hyperplasia and not from embryonic hydrocephalus. Continued work with this and other models is required to delineate new mechanisms and to offer alternative postulates for the origin of dysraphic lesions.

Animals↗
PubMed1977

Kloeckera apis st. nov.; the imperfect state of Hanseniaspora guilliermondii Pijper.

K. apiculata var. apis (nom. nud.) was found to be the imperfect state of H. guilliermondii Pijper by a high degree of DNA reassociation. The name is validated and raised to species rank, K. apis Lavie ex Smith, Simione and Meyer. K. apis and H. guilliermondii could be distinguished from H. uvarum and H. valbyensis by a low DNA reassociation and by growth at 37 C.

DNA↗
PubMed1977

The reaction of nerve tissue to various suture materials: a study in rabbits.

Adult, male white New Zealand rabbits were used to compare two new synthetic suture materials, polyglycolic acid (Dexon) and polypropylene (Prolene), with wire, plain catgut, and silk. The purpose of the study was simply to determine the reaction of nerve tissue to each of the five different materials. No attempt was made to measure functional results. The nerves were examined grossly and microscopically in an effort to evaluate which suture incited the least host reaction. Although no difference was noted in the initial cellular response, Prolene was shown to incite the least fibrolastic response. Silk evoked the most marked fibroblastic response.

Animals↗
PubMed1977

Inverse cerebellum and occipital encephalocele. A dorsal fusion defect uniting the Arnold-Chiari and Dandy-Walker spectrum.

The malformation of inverse cerebellum and occipital encephalocele is situated morphologically between the Arnold-Chiari and Dandy-Walker malformations. In the three reported cases, hydrocephalus was not present, concomitant malformations of the lamina terminalis were present in two, and polymicrogyria was found in all three. The primary defect in the malformation is a complex occipital encephalocele composed of miniature hemispheres connected to the brain stem by an extension of the midbrain tectum. The cerebellar folia extend ventrally and cover the basilar artery. We propose that the encephalocele arises through the processes of overgrowth and dysraphism and thus falls into the organogenetic malformations of Yakovlev. Supporting this theory is the consistent observation of the duplicate hemispheres in the encephalocele and the hydromyelia in the examined spinal cords.

Arnold-Chiari Malformation↗
PubMed1976

Extraskeletal myxoid chondrosarcoma: a clinicopathological study.

Extraskeletal myxoid chondrosarcoma is a rare tumor of cartilagenous origin, with only 41 previously reported cases. It has a distinctive histologic pattern and should be distinguished from chondrosarcoma of bone because of its different behavioral pattern. The light microscopic, histo-chemical and electron microscopic features of such a tumor are reported.

Adult↗
PubMed1976

Sweat gland carcinoma: a clinico-pathological reappraisal.

A case of sweat gland carcinoma arising from the right fifth finger which later metastasized to the regional lymph nodes and the lungs is the subject of this report which attempts to establish further the true characteristics of this definite pathological entity. The diagnosis of sweat gland carcinoma has been loosely applied to a variety of lesions, and it was not until recently that more exact and appropriate criteria were used to establish the diagnosis of sweat gland carcinoma. The case reported in this manuscript possesses most if not all the criteria necessary to make a diagnosis of sweat gland carcinoma. Further review of the literature shows that this is a rare and aggressive neoplasm as this case illustrates. Radical surgery of the primary lesions with radical regional lymph node dissection whenever possible is recommended for the initial treatment, and combination chemotherapy and radiotherapy may be employed in the palliative treatment of the more advanced forms of the disease.

Adenocarcinoma↗
PubMed1975

Physiological and DNA characterization of Candida maltosa, a hydrocarbon-utilizing yeast.

Selected yeast classified as Candida sake van Uden et Buckley were examined for their physiological, morphological and immunological properties and their DNA relatedness. Candida maltosa Komagata, Nakase et Katsuya is herein recognized as a species separate from C. sake, Candida maltosa was distinguished from C. sake and from C. tropicalis by insignificant DNA reassociation. In addition, C. maltosa was distinguished from C. sake by its higher maximal growth temperature and lower guanine plus cytosine content of its DNA and from C. tropicalis by its failure to utilize soluble starch for growth and its resistance to cycloheximide. The species C. cloacae and C. subtropicalis are placed in synonymy with C. maltosa.

Alkanes↗