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Biomedical subjects

R David

Publications and source records attributed to R David.

At least 199 records · Page 11Linked to original sources
PubMed1982

Tannic acid-glutaraldehyde fixative and pleomorphic adenomas of the salivary gland: an ultrastructural study.

Four cases of pleomorphic adenomas of parotid glands were fixed by immersion in a mixture of 4% tannic acid and 3% glutaraldehyde followed by OsO4 postfixation and heavy metals staining. This clearly visualized the presence of dense amorphous elastic fibers in cellular and myxochondroid areas. The dense amorphous fibers were associated with varying numbers of peripheral filaments which appeared sometimes as bundles of parallel fibrils without intermingled amorphous material. These intermediate-sized filaments were seen indirect continuity with similar intracellular filaments with or without interposition of basal-membrane-like material and/or with extracellular filament-containing vesicles. It is suggested that these filaments are synthesized intracellularly and released into the extracellular space by neoplastic myoepithelial cells mainly by cytoplasmic vesicle separation. In addition, small round vesicles with a dense core of amorphous material and staining characteristics identical to those of extracellular elastin were frequently seen in the peripheral parts of these myoepithelial-like cells. It is possible that these dense-cored vesicles have a secretory function and contain a precursor of elastin.

Adenoma, Pleomorphic↗
PubMed1982

Treatment of acquired aphasia: speech therapists and volunteers compared.

This paper reports on a multicentre trial comparing the effects of speech therapists and untrained volunteers on recovery from aphasia following stroke. One hundred and fifty-five patients entered the study and 96 completed it. Patients in both treatment groups improved, and there were no differences overall in the amount of progress made. A small subgroup of patients who started treatment much later had equivalent initial scores and made almost as much progress as those who started earlier. It is suggested that the improvement in communication which occurred during treatment may be due both to the appropriate stimulation which was based on detailed and accurate speech therapy assessment, and to the regular support and encouragement provided within the therapeutic relationship.

Aged↗
PubMed1982

Study of granulocyte-macrophage progenitor (CFUc) preservation after slow freezing of bone marrow in the gas phase of liquid nitrogen.

Storage of human hematopoietic stem cells has been made possible through effective preservation of viability by freezing technique. We have studied the quantitative and qualitative aspects of granulocyte-macrophage precursor (CFUc) recovery from 29 bags of frozen bone marrow stored at - 160 degree C in the gas phase of liquid nitrogen for several months or years. it has been shown that with the freezing and preservation technique used, over 75% of the proliferative capacity of the cryopreserved CFUc was recovered. The influence of various factors on the quality of bone marrow preservation was studied and showed that dimethylsulfoxide (DMSO) appeared to cause substantial loss of CFUc at 4 degree C. Evaluation of CFUc in vitro is essential for determining the quality and richness of cryopreserved bone marrow with a view to using such marrow for autologous grafting intensive chemotherapy or total body irradiation in patients with hematological malignancies or solid tumors. No correlation was found between the number of nucleated bone marrow cells and CFUc content.

Adolescent↗
PubMed1981

[Diagnosis and treatment of lacrimal pathway lesions].

The experience of a clinic dealing exclusively with lacrimal system problems is reported. 2,002 patients (2,497 eyes) were treated over the course of eight years. The great majority of patients were children under the age of 4 years. the etiology of the lacrimal dysfunction varied according to age. In infants and children under four 98% of the cases were of congenital defects. The most frequent causes in adolescents and adults was trauma, and in the elderly, inflammation. Inflammation of the lacrimal sac was more than twice as common in females, and the right side was more often affected that the left (4:3).

Adolescent↗
PubMed1981

"Hyaline cells" in pleomorphic adenoma of salivary gland origin.

Fifty-two cases of pleomorphic adenoma of minor salivary gland origin and seventy-two cases of pleomorphic adenoma of major salivary gland origin were examined for the presence of hyaline cells (plasmacytoid cells). Hyaline cells were found in 38 percent of the minor salivary gland cases and 21 percent of the major salivary gland cases. When stained with hematoxylin and eosin, the hyaline cells exhibited an eccentric nucleus and a striking homogenous, ground-glass, eosinophilic cytoplasm. At the ultrastructural level, the cytoplasm of the hyaline cells was closely packed with intermediate-sized filaments having no apparent orientation. It is suggested that the hyaline cells are modified myoepithelial cells.

Adenoma, Pleomorphic↗
PubMed1981

Factors affecting sperm motility. VII. Sperm viability as affected by change of pH and osmolarity of semen and urine specimens.

The effects of pH and osmolarity of semen and urine specimens on motility and velocity of human spermatozoa were studied objectively with the aid of the multiple exposure photography (MEP) method. The pH of fresh ejaculates ranged from 7.2 to 8.2 and specimens were slightly hyperosmotic ranging between 300 to 380 mOsm/kg. Gradually changing the pH and osmolarity to either side of normal values led to progressive loss of sperm motility. However, sperm velocity was slightly increased by mild alkalinization and hyperosmolarity. Spermatozoa that became immobilized by acidification regained their motility shortly after pH was restored to normal values. In the majority of instances spermatozoa lost their motility when mixed with fresh urine specimens. Neutralization of urinary pH could not protect them from this effect unless urine osmolarity was also isotonically adjusted. It is suggested that patients with retrograde ejaculation should adequately increase their fluid intake before recovery of sperm from their bladder for artificial insemination.

Humans↗
PubMed1981

Quantitative trabeculectomy.

The technique and results of a trabeculectomy are presented where the desired final intraocular pressure (IOP) is obtained by means of adjusting the thickness of sclerocorneal tissue removed to the initial pressure. The procedure was used in 35 eyes with all types of glaucoma and pre-operative pressures of up to 50 mmHg. In 78.3% of cases one operation was sufficient to control the IOP without additional medication. Two eyes had to be reoperated on, and 7 more needed additional pressure-lowering medication. The overall success rate, therefore, rose to 97.3%. The only failure occurred in an eye with irreducible acute angle-closure glaucoma where malignant glaucoma complicated the trabeculectomy. Complications included hyphaema (3), shallow anterior chamber (7)--with or without choroidal detachment--and transient rise in the IOP. All complications subsided with conservative therapy.

Glaucoma↗
PubMed1981

Racism, society, and disease: an exploration of the social and biological mechanisms of differential mortality.

Racial differentials in mortality provide important insight into the nature of mass disease in capitalist society. Not only are the differentials sizable in magnitude, they are consistent for multiple causes of death and appear to evolve in response to social development. The relationships among social factors and the biological and physical agents of disease can be identified through racial contrasts and a pattern of causation which applies to both the minority and majority populations described. Furthermore, the impact of exploitation as the primary disease-mediating factor under capitalist social relations can be estimated. This paper attempts to combine an analysis of bio-medical mechanisms with Marxist social theory in a comprehensive framework for the study of the social origins of racial differentials.

Black or African American↗
PubMed1981

Water intoxication in normal infants: role of antidiuretic hormone in pathogenesis.

Eight infants, 2 to 5 months of age, who were seen somnolence or irritability, seizures, and hypothermia are described. The symptoms developed following the ingestion of dilute formula. All infants were hyponatremic. Three patients were identified by the symptom complex and were evaluated prior to any therapeutic intervention. Plasma arginine vasopressin concentration and urinary osmolality were either normal or increased despite hyponatremia and decreased serum osmolality. These data, coupled with rapid biochemical and clinical improvement following fluid restriction and/or administration of 3% NaCl, strongly implicate the excessive release of arginine vasopressin in the pathogenesis of this syndrome of water intoxication.

Arginine Vasopressin↗
PubMed1981

Effect of ethanol upon placental uptake of amino acids.

The effect of ethanol infusion upon placental uptake of amino acids was studied in pregnant sheep. Blood ethanol levels of 150-260 mg/dl obliterated the normal uptake of amino acids by the in vivo placenta. However, when human placental villi were incubated in vitro with ethanol at 300 mg/dl, there was no inhibition of uptake of 14C alpha-amino isobutyric acid (AIB). In contrast, 2-20 mM, but not 50 or 200 micro M, acetaldehyde significantly inhibited AIB uptake (% inhibition at 90 min: 2 mM, 23.5 +/- 9.6%; 5 mM, 33.8 +/- 4.7%; 10 mM, 54.6 +/- 2.9%; 20 mM, 61.5 +/- 7.5%; p less than 0.01 for all 4 concentrations). When human placental villi were preincubated with 10 micro M acetaldehyde, washed, and incubated with 14C-AIB in the absence of acetaldehyde, there was significant residual inhibition of AIB uptake. The data suggest that ethanol-associated placental injury may contribute to the pathophysiology of the fetal alcohol syndrome.

Acetaldehyde↗
PubMed1980

[Studies of immunological status, following autologous bone marrow transplantation in man (author's transl)].

Following transplant, circulating immunoglobulin levels fell moderately and remained depressed less than 2 months for IgG, and for variable and longer periods of time for IgM and IgA. Repeated quantitative determinations of antibodies against multiple antigens did not show any decrease in the pretransplant levels. Indeed some patients developed herpes and cytomegalovirus infections to which they responded by a sharp increase in antibody titers. In 2 cases, a primary immunization was demonstrated (against CMV and BK virus) with increasing levels of IgM and IgG antibodies. Lymphocyte counts in peripheral blood returned to 500 mm# between day 10 and 29 (median day 18) and to pretransplant values within 6 weeks. Non specific stimulation of lymphocytes by mitogens in the immediate post-transplant period showed a decreased response to PHA and Con A, whereas the responses to pokeweek mitogens and alloantigens were only slightly diminished. The degree of the responses was related to the dose of cryopreserved marrow infused. We conclude that:--although the minimum dose for autologous bone marrow transplantation in man is around 0,5 10(8) nucleated bone marrow cells/Kg, much higher doses should be used to ensure faster and better restoration of immune reactivity.--The similarity of the immunological dysfunction following autologous and allogeneous bone marrow transplantation suggest that, in the immediate post-transplant period, the role of GVHD in cellular immunity depression may be minimal.

Bone Marrow Transplantation↗
PubMed1980

Elastosis in benign and malignant salivary gland tumors. A histochemical and ultrastructural study.

One hundred sixteen cases of various types of salivary gland tumors were examined for the presence of elastic tissue. Almost all the pleomorphic adenomas (97%) and all the malignant pleomorphic adenomas contained elastic tissue in varying amounts. A high percentage (82%) of adenoid cystic carcinomas also contained elastic tissue but the overall quantity was significantly less than in pleomorphic adenomas. All other salivary gland tumors studied, i.e. adenolymphomas, oxyphilic adenomas, mucoepidermoid tumor, and various variants of monomorphic adenomas, were devoid of significant elastic tissue. At the ultrastructural level, the elastic fibers were mainly seen close to neoplastic myoepithelial-like cells, and all stages of elastogenesis were present, ranging from young elastic fibers with a high microfibrilelastin ratio, usually associated with basal-membrane-like material, to mature fibers consisting mainly of an amorphous electron lucent central elastin component. It is postulated that elastic tissue in the salivary gland tumors is produced by the myoepithelial-like tumor cells rather than by tumor stromal induction as has been described in some types of breast carcinomas.

Adenolymphoma↗
PubMed1980

Langerhans' cells in a pleomorphic adenoma of submandibular salivary gland.

Large numbers of round and dendritic cells similar to Langerhans' cells of normal epidermis and other epithelia were seen within a pleomorphic adenoma of the submandibular salivary gland. These cells, which were present only in areas of non-cornifying epidermoid metaplasia, exhibited Birbeck granules with isolated terminal vesicles, cytoplasmic microfilaments, microtubules, and a few poorly developed intercellular junctions.

Adenoma, Pleomorphic↗
PubMed1980

Aberrant testicular differentiation in 46,XY gonadal dysgenesis: morphology, endocrinology, serology.

In an infant with gonadal dysgenesis and somatic anomalies, the internal and external genitalia were female but the gonads contained tubular structures suggesting male differentiation. The karyotype was 46,XY with no evidence of structural aberration or mosaicism. Hormonal metabolism and H-Y antigen expression were assayed in cultured gonadal cells. Although unable to synthesize testosterone, the cultured cells were able to convert it to dihydrotestosterone. H-Y antigen was present, perhaps at a level lower than that in cells from normal XY males. Our observations indicate that a modicum of testicular organogenesis may precede the involution that results in a streak gonad in some cases of gonadal dysgenesis.

Cells, Cultured↗