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Biomedical subjects

M Goldfinger

Publications and source records attributed to M Goldfinger.

At least 19 recordsLinked to original sources

Isolation of plasma membranes, Golgi bodies and mitochondria of Xenopus laevis morulae. Identification of plasma membrane proteins.

Homogenates of Xenopus morulae at the 16-32 cell stage were centrifuged on discontinuous sucrose gradients. Isolated fractions were identified by electron microscopy (EM) as mitochondria, a fraction enriched in Golgi vesicles, and plasma membranes. A special effort was made to prepare plasma membranes free of cytoplasmic contaminants. The resulting purified plasma membranes appeared morphologically identical to plasma membranes in situ. The external surface is covered with a fibrillar coat while vesicles are seen attached to their inner surface. O'Farell's method (1975) was used to obtain protein patterns of the various fractions on 2-dimensional gel electrophoresis. Each fraction displayed a specific pattern. By comparing the different patterns, it was possible to identify a group of proteins as belonging to the plasma membrane fractions. Labelling of cell surface with sulfo-N-hydroxysuccinimido-biotin together with differential extraction of proteins has allowed us to tentatively allocate these proteins in different structures of the plasma membrane fractions. The data presented in this paper corroborate and extend our ultrastructural studies on neogenesis of interblastomeric plasma membranes (Bieliavsky and Geuskens, 1990).

Animals

Autonomous mesoderm formation in blastocoelic roof explants from inverted Xenopus embryos.

Xenopus eggs, artificially fertilized, were prevented from undergoing equilibrium rotation by incubation in medium containing ficoll. Three orientations were selected: normal, with animal pole uppermost; inverted, with vegetal pole away from gravity; and an off-axis orientation, with embryos tilted approximately 90 degrees from the animal-vegetal axis. At blastula stage 8, cells forming the blastocoelic roof were cultured in isolation as explants. These cells are normally fated to from epidermis ventrally and neural derivatives dorsally. Unexpectedly, in the fragments originating from inverted or 90 degrees-off-axis embryos, axial structures were found: notochord, somites, neural cells, cement glands, and sometimes sensory organs. Inverted eggs could be exploited in studies of mesodermal specification.

Animals

Presence of high molecular weight glycans on the surface of germ and embryonic cells of Xenopus laevis.

Xenopus laevis male germ cells, fertilized eggs and gastrula cells were labelled with 3H labelled sodium borohydride reduction after galactose oxidase treatment. After pronase digestion, the bulk of the label is carried by high molecular weight glycans (greater than or equal to 6,000 D). The high molecular weight of these labelled glycans and their susceptibility to degradation by endo-beta-galactosidase suggest that they may be related to the polylactosaminoglycans.

Animals

Intraoperative ultrasound in the conservative resection of testicular neoplasms.

In a series of approximately 400 patients investigated for oligospermia 4 had small testicular tumors demonstrated by high resolution real-time ultrasound. The lesions ranged in size from 3 to 6 mm., were clinically impalpable and were demonstrated on repeated sonograms. Exploration was done in all 4 patients with the aid of intraoperative high resolution ultrasound. This procedure allowed for conservative resection of the tumor with preservation of the testicle. The pathological diagnosis in all cases was benign Leydig cell tumor.

Adult

Magnetic resonance imaging, computed tomography, and radionuclide scintigraphy in detection of liver metastases.

A series of 100 patients with suspected hepatic metastases was studied with magnetic resonance (MR), unenhanced computed tomography (CT), and radionuclide (RN) scintigraphy. Each set of images was read by three clinicians using a five-point scale to allow receiver operating characteristic (ROC) analysis using truth data derived from clinical review. Performance was measured by the areas under the ROC curves (0.940 +/- .018 for MR, 0.951 O +/- .013 for CT and 0.943 +/- .013 for RN) which were statistically not significantly different. We conclude that at their present level of development these three diagnostic examinations have equivalent performance and that MR is not superior in the detection of hepatic metastases.

Evaluation Studies as Topic

Thyroid cartilage imaging with diagnostic ultrasound. Correlative studies.

In 1976, Noyek observed that the thyroid cartilage framework of the larynx could be imaged by diagnostic ultrasound; the image appeared uniquely independent of the presence or absence of calcification. It was suggested that ultrasound, with its simple, nonroentgenographic, noninvasive features, might permit screening detection of thyroid cartilage destruction. It might, therefore, give direction to better computed tomographic (CT) imaging, and, specifically, more effectively identify T4 laryngeal cancer. Since that time, with improving generations of ultrasound transducers, more than 130 clinically correlated laryngeal ultrasound examinations have been recorded. Thirty CT, ultrasound, and pathologically correlated advanced cases of laryngeal carcinoma were critically evaluated by the Departments of Otolaryngology and Radiology at Mount Sinai Hospital, Toronto. Our diagnostic imaging approach has resulted in remarkably improved thyroid cartilage imaging by CT when "directed" by preliminary ultrasound.

Carcinoma

Sonographic guidance of thyroid needle biopsy.

We describe a new technique for sonographically guided needle biopsy of the thyroid using high-resolution real-time ultrasound. It proved to be highly effective for obtaining diagnostic samples from thyroid nodules in 13 of 14 patients who otherwise could not have a diagnostic thyroid aspiration because their nodules were in difficult locations or were not palpable. We believe that sonographic guidance will be important to those physicians employing thyroid needle biopsy.

Biopsy, Needle

Diffuse lymphomatous polyposis of the gastrointestinal tract. A case report with immunohistochemical studies.

A case of diffuse lymphomatous polyposis of the gastrointestinal tract is reported. The patient presented with abdominal pain and weight loss and x-rays revealed multiple polyps involving the entire gastrointestinal tract. Biopsies confirmed the diagnosis of lymphomatous polyposis. The patient also had involvement of the bone marrow and supraclavicular lymph node. Immunologically this lymphoma was characterized as a monoclonal proliferation of B lymphocytes bearing immunoglobulin M, type kappa. Diffuse lymphomatous polyposis of the gastrointestinal tract appears to be a generalized malignancy of uncommitted B cells of Peyer's patches. The migratory properties of these cells may account for the tendency to dissemination of lymphomatous polyposis. Diffuse lymphomatous polyposis of the gastrointestinal tract is a distinct entity, separate from the diffuse gastrointestinal lymphoma known as Mediterranean-type lymphoma.

Aged

Percutaneous gastrostomy for enteral feeding.

Over a period of 18 months, percutaneous nonendoscopic gastrostomy using the Seldinger technique was successfully performed in 32 adults for enteral feeding. There were no deaths or major morbidity related to the procedure. Three patients died of existing disease within 30 days; one had peritoneal irritation following dislodgement of the catheter two days after the procedure but responded to conservative treatment with antibiotics alone. The authors conclude that this procedure is simple and safe and represents the preferred method of gastrostomy for enteral feeding.

Adolescent

Endometriosis: an unusual cause of ureteral obstruction.

Endometriosis is a common disorder, affecting women in the child-bearing years. While urologic involvement is rare, the bladder is more often affected than the ureter. The authors describe the case of a 30-year-old woman who had unilateral ureteral obstruction secondary to an isolated periureteral retroperitoneal area of endometriosis. The theories of histogenesis are discussed. Current treatment consists of surgery or hormonal manipulation or a combination of the two.

Adult

Pitfall in the investigation of splenic trauma.

A patient with suspected splenic trauma is reported in whom, because of an anatomic variant, both radionuclide and sonographic examinations were misleading and led to the erroneous diagnosis of splenic laceration. Confusion arose because of an overlying left lobe of liver and this was clarified by biliary scintigraphy.

False Positive Reactions

Diagnostic ultrasound imaging of parotid disease--a contemporary clinical perspective.

Diagnostic ultrasound provides fast, simple screening soft tissue information for evaluation of both parotid glands on the same single image display. This information augments the findings on history and physical examination and directs further radiologic studies if indicated. This manuscript attempts to establish the role for diagnostic ultrasound in the evaluation of patients with diffuse and focal parotid disease. It also attempts to establish a more definitive role for diagnostic ultrasound in relation to other diagnostic imaging modalities.

Cysts

Thyroid tumor imaging.

Clinical assessment of a patient with a focal or diffuse thyroid tumor is but the first step in diagnostic evaluation. The diagnostic imaging process augments information obtained by the inspecting eye and the palpating hand; it allows the qualification (for example, cystic v solid) and the quantification (for example, size, extension, and assessment of physiologic function) of the thyroid tumor mass. This diagnostic input allows the establishment of a more realistic provisional diagnosis and directs a rational treatment approach to the patient. This presentation reviews the major imaging modalities available for thyroid tumor evaluation: diagnostic ultrasound, radionuclide scans, and conventional radiology and computed tomography. The applications of these various modalities and their critical potentials and limitations are placed in a contemporary clinical setting. It is hoped that an increasing familiarity with these imaging modalities will give better direction to the specialist in otolaryngology--head and neck surgery and greater surgical benefit to his or her patients.

Adenocarcinoma

Biochemical characterization of lysosomes in unfertilized eggs of Xenopus laevis.

Relations between lysosomes and yolk platelets of amphibian eggs have been suggested. This work demonstrates the presence of acid hydrolases in oocytes induced to ovulate in vitro. About 40% of the acid hydrolases are found in a sedimentable fraction, and, in accordance with the lysosomal concept, they display structural latency. Biochemical data did not indicate any association between lysosomal enzymes and yolk platelets. The mechanism of yolk resorption is discussed and it is suggested that the fusion of lysosomes and yolk platelets might be one of the mechanisms involved in yolk digestion.

Acetylglucosaminidase