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Biomedical subjects

R Guggenheim

Publications and source records attributed to R Guggenheim.

At least 37 records · Page 2Linked to original sources
PubMed1981

Morphologic studies in saphenous vein grafts for aorto-coronary bypass surgery. Part I: Morphology of the Graft using ordinary surgical preparation techniques.

Vein bypass grafts in 8 patients were examined by light microscopy (LM) only or, in addition, by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) before stretching, after stretching and immediately before implantation. Before stretching, the endothelium showed only discrete changes and detachment of the endothelium was rare. After stretching severe endothelial damage was evident, including loss of large areas of endothelium and extensive endothelial tears. Before implantation there had been an extension of the tears and the endothelial detachment in individual preparations. The most important factor causing damage is stretching of the vein. The incubation medium may also play a significant role. Damage incurred before operation or during removal, and hypoxia are of lesser importance. By avoiding endothelial damage it should be possible to limit the occurrence of early postoperative thrombosis and possibly severe late changes as well.

Coronary Artery Bypass↗
PubMed1981

Morphologic studies in saphenous vein grafts for aorto-coronary bypass surgery. Part II: Influence of a pressure-limited graft dilation.

The evidence of considerable damage caused by stretching to the vein transplants for aorto-coronary bypasses led us to a modified technique of vein dilation that allows control and limitation of the pressure to which the veingraft is exposed. The efficiency of this procedure in terms of reduced damage to the vascular wall was investigated by microscopic and electronmicroscopic methods. It could be shown that the integrity of the intimal layer of vein grafts can be maintained to a high degree. Clinically this implies that the long-term patency rate of aorto-coronary veingrafts may be improved. This will be subject to further coronarographic studies during the follow-up of a present series of patients.

Aged↗
PubMed1981

Demonstration of supra-ependymal 5-HT nerve fibres in human brain and their immunohistochemical identification in rat brain.

When samples of the ventricle surfaces of human post-mortem brain were examined by scanning- and transmission electron microscopy, varicose nerve fibres could be seen traversing among the cilia and microvilli of ependymal cells. The varicosities contained numerous small electron-lucent vesicles and frequent large electron-dense vesicles, and were usually nonsynaptic but occasionally anchored to the surface by desmosome-like junctions. Supra-ependymal nerve fibres were observed in the lateral ventricles (e.g., n. caudatus), foramen of Monro (stria medullaris), third ventricle (habenula) and floor of the fourth ventricle in brains of the five cases examined. However, only in one of these was a yellow formaldehyde-induced fluorescence observed (on the fourth ventricle floor). Its discrete granular appearance, rapid fading and colour were typical of supra-ependymal 5-HT nerve fibres observed in rat brain. Very recent investigations on serial cryostat sections of rat brain ventricle regions revealed the absence of an immunohistochemical reaction with antisera to substance P, leu- and met-enkephalin and glutamic acid decarboxylase, but the presence of a reaction with 5-HT antiserum. The target for impulse-released 5-HT from this nonsynaptic 5-HT nerve plexus, bathed in cerebrospinal fluid, is not yet known.

Animals↗
PubMed1980

Surface characteristics of oocytes from juvenile mice as observed in the scanning electron microscope.

The in vivo and in vitro development of the zona pellucida as well as the vitelline membrane surface of oocytes isolated from juvenile mice aged between 8 and 30 days p.p. were investigated by scanning electron microscopy. In vivo a consistent development of the zona pellucida surface can be observed, namely the formation of a fibrous network like structure interspersed with numerous pores. After enzymatic removal of the zona pellucida the surface of the vitelline membrane was studied. In "normal" oocytes with intact germinal vesicles, microvilli were distributed over the entire oocyte surface in all age groups investigated. After resumption of meiosis in vitro a characteristic differentiation on the vitelline membrane occurs. A glabrous polar region appears in primary oocytes and a glabrous polar body in secondary oocytes. The same differentiation in surface organization could be observed in the in vivo precociously matured oocytes.

Age Factors↗
PubMed1980

Serum digoxin concentration and age.

A review was conducted of the charts of 79 consecutive inpatients (age range, 17-93 years) who were in a steady state with respect to digoxin dosage, and had serum creatinine levels below 1.6 mg/dl or urea nitrogen levels below 26 mg/dl. In these patients whose renal function was not impaired, there was no correlation between age and the serum digoxin level normalized for dosage. Concurrent administration of quinidine significantly elevated digoxin concentration. Patients with congestive heart failure showed a higher serum digoxin level than did those without heart failure. Thus, age appeared to have little, if any effect on the relationship between the dose of digoxin and the steady-state serum level when the factor of impaired renal function (often associated with aging) was eliminated.

Adolescent↗
PubMed1980

Transmission and scanning electron microscopy of epididymis in male mice receiving estrogen during gestation.

In estrogen-induced cryptorchidism in mice, differentiation of the epididymis is arrested. Transformation of the Wolffian duct into the epididymis, which is androgen dependent, is incomplete. Simultaneous administration of estrogen and HCG prevents cryptorchidism, and the appearance of the epididymis in the transmission and the scanning electron microscope is similar to the appearance of the epididymis of control animals. According to our studies the epididymis differentiation is a prime mover in a process which leads to the descensus of the testis.

Animals↗
PubMed1979

[Studies on pigmented surface wrinkling retinopathy by scanning electron microscopy (author's transl)].

The light- and scanning electron microscopic appearance of 3 areas of pigmented epiretinal fibroplasia (pucker) are described in an eye removed following detachment surgery. The centre of each area of pucker consists of a fibroglial sheet covered by retinal pigment epithelium. The surface morphology of these cells resembles typical or slightly degenerated epithelium. Extensive areas of these pigment epithelial sheets were pigmentfree. There was no evidence that the pigment epithelial sheets exerted either direct or indirect traction on the inner surface of the retina. The origin of these cells and their role in the formation of retinal wrinkling is discussed.

Aged↗
PubMed1979

Hormonal influences on the dog prostate--a correlation study with light microscopy, transmission and scanning electron microscopy.

Dog prostates under defined hormonal influences were investigated by light microscopy (LM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The normal acinar cell apices exhibited well-developed, densely packed microvilli. TEM demonstrated numerous secretory granules, indicating a high secretory activity. Following castration, the acinar cells of the dog prostate showed rounded apices. Most of the microvilli disappeared and only knob-like protrusions were seen. Castrated dogs following administration of 3 alpha-androstandiol showed fewer microvilli than the controls; however, a well-developed undulating surface could be observed. Castrated dogs given 3 alpha-androstandiol and cyproterone acetate showed almost completely atrophic glandular cells. Prostates of dogs with spontaneous benign prostatic hyperplasia (BPH) were characterized by pleomorphism of cell shapes and surfaces. The different hormonal influences induced changes of the prostatic surface structures and secretory activity.

Androstanols↗
PubMed1979

Comparative scanning and transmission electron microscopy of the prostatic gland in different species (mouse, rat, dog, man).

Man, dog, rat and mouse prostatic glandular cells were compared by light microscopy (LM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). In rodents and dogs, a merocrine secretion exists, and in these species the undulating surface represented a confluence of secretory granules. The prominent secretory blebs observed in dog and human benign prostatic hyperplasia (BPH) corresponded to apocrine secretions. Also variations in the amount of secretory activity were seen. Androgenic hormones were responsible for the differentiation of the prostatic epithelial cells during development. Therefore, an absence of microvilli as well as the appearance of ruffles, microplicae, and bare cells were seen in the prepuberal and castrated rat. In the elderly rat and in human BPH, a pleomorphism of the apical cell surface was evident.

Age Factors↗
PubMed1978

[Studies on fibrous and fibro-glial surface wrinkling retinopathy by scanning electron microscopy (author's transl)].

The scanning electron microscope was used to examine 16 cases of epiretinal membrane formation and retinal puckers which occurred in a variety of primary retinal disorders. In this first section the authors describe three types of epiretinal membranes: (1) Fibrous acellular membranes with and without vitreous adhesions. Retinal puckering was caused by vitreous traction with collagen strands binding the residual folds. (2) Fibrous membranes containing isolated glial cells. (3) Fibrous membranes partly covered by sheets of glial cells. In all three forms the acellular fibrous component is believed to represent vitreous cortex remnants. The invariable presence of these fibrous membranes at sites of retinal pucker and their relationship to wrinkled internal limiting membrane suggests that contraction of these membranes is responsible for retinal puckering. Morphological evidence of glial membrane contraction and collagen production by glial cells was not found.

Connective Tissue↗
PubMed1978

Long-term cultivation of plasma cell leukemia cells and autologous lymphoblasts (LCL) in vitro: a comparative study.

Two long-term cell lines were established in vitro from the peripheral blood of a patient with plasma cell leukemia: one line with plasma cell proliferation, the other with lymphoblastoid cell proliferation (LCL). The 9-month-old plasma cell line showed the typical morphology of plasmoblasts. The cells neither had B- nor T-lymphocyte characterisitics, were EBV negative, and showed aneuploidy with various marker chromosomes, including the 14 q+ marker. The cytogenetic findings indicate a monoclonal proliferation of the plasmacells. No tumor growth in thymusless nude mice could be induced upon intracranial inoculation with these cells. In contrast, the autologous LCL, cultured after addition of exogenous EBV, showed the characteristic markers of lymphoblastoid cells, with the typical morphology of pear- and handmirror-shaped lymphoblasts, growing in clumps. They had C3- and Fc-receptors, surface-Ig, E-rosette-negativity, a diploid karyotype, and EBV dependent macromolecule synthesis. They lymphoblastoid cells produced intracranial tumors in nude mice in 8 out of 8 attempts.

Adult↗
PubMed1977

[Findings on retinal surface by scanning electron microscopy. II. Vitreous detachment (author's transl)].

The authors describe their findings by scanning electron microscopy of the surface of the retina following secondary and primary senile posterior vitreous detachment. These findings are correlated with those of transmission electron microscopy. Extended nets formed by vitreous fibrils can be found on the retinal surface. The fibrils form a continuous feltwork, which cannot be traced by biomicroscopy or dissection of enucleated globes. This feltwork desintegrates in places or over a wide area and the basal membrane of the Müller cells becomes exposed. Structural differences in consequence of the two examination techniques well as possible artifacts are shown.

Age Factors↗
PubMed1977

[Findings on retinal surface by scanning electron microscopy. III. Epivascular glial clusters (author's transl)].

The findings by scanning and transmission electron microscopy of multiple glial excrescences from the retina into the cortical vitreous body are described. These formations are located in lines above superficial retinal vessels. The findings are compared with those from light microscopy of similar formations. The pathogenesis and the possible significance as retinovitreal attachments for rhegmatogenous defects of the retina and for posterior vitreous detachments are discussed.

Aged↗
PubMed1976

[Findings on retinal surface by scanning electron microscopy. I. Retinal holes (author's transl)].

The findings by scanning electron microscopy on three retinal holes are described. An outgrow of a glial membrane with microvilli from the holes to the retinal surface can be seen. This epiretinal cell membrane grows on a felt of collagen fibres of the vitreoretinal borderlayer. Rudiments of visual receptors project from the deep walls into the holes. The layer of the pigment epithelial cells beneath the holes is remarkable by the abundance of microvilli.

Female↗