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Biomedical subjects

M Goldberg

Publications and source records attributed to M Goldberg.

At least 469 records · Page 26Linked to original sources
PubMed1987

Rapid-freezing and malachite green-acrolein-osmium tetroxide freeze-substitution fixation improve visualization of extracellular lipids in rat incisor pre-dentin and dentin.

Rat incisor tissue sections were fixed by a modified version of the malachite green-aldehyde method (MGA) composed of rapid-freezing, malachite green-acrolein staining, and osmium tetroxide freeze-substitution (Fr.MGAO). In the pre-dentin, a thick, dense network of branched fibrous structures was observed. Cryotechniques allowed visualization of complexes about twice as thick and dense as the aggregates visualized on MGA-treated sections. Pretreatment of rapid-frozen samples with methanol before freeze-substitution fixation and staining prevented staining of the complexes otherwise revealed by the Fr.MGAO method. Electron-dense material stained by this procedure resisted de-mineralization with EDTA, while intramitochondrial granules and dentin crystallites were dissolved. EDTA treatment demonstrated unequal distribution of Fr.MGAO staining in dentin in the form of tiny dots underlining the collagen fibers. These results support the concept that rapid-freezing, followed by staining and freeze-substitution fixation, improves preservation of the phospholipids visualized as extracellular matrix components in pre-dentin and dentin of rat incisors.

Acrolein↗
PubMed1987

[Post-natal development of tooth structures in Didelphis albiventris].

The post-natal development of tooth germs has been studied in the opossum or South American marsupial (Didelphis albiventris) between the 2nd and 10th week. Dentinogenesis starts around the 3rd week. The enamel which begins to appear at this stage is deposited until the 8th-10th week. At 10 weeks, the enamel enters the maturation phase. It is unlikely that enamel tubules in these marsupials have a cellular origin. No specific histochemical reaction predicts their appearance which is observed in the mature tooth. This fact suggests that their origin is related either to enamel maturation or to the beginning of tooth function. The mineralizing dentine front presents on the one hand calcospherites where peritubular dentine is formed before intertubular dentine, and on the other hand a radiating mineralizing structure. These two aspects are exceptional in Vertebrates.

Amelogenesis↗
PubMed1987

Neurosurgical, obstetric and endocrine aspects of meningioma during pregnancy.

A 34-year-old woman presented with symptoms due to a cerebral meningioma during pregnancy. The meningioma tissue was found to be positive for progesterone but not estrogen receptors. The relationship of meningiomas to pregnancy, female sex, and breast cancer is discussed with emphasis on the presence of hormone receptors in the tumor tissue. The high incidence (39 to 100%) of progesterone receptors in meningiomas may explain the increased percentage of its discovery during pregnancy. Neurosurgical intervention during pregnancy should be confined to cases associated with neurological deficit. Cesarean section is indicated only in the presence of a major intracranial mass effect.

Adult↗
PubMed1987

Visualization of proteoglycans and membrane-associated components in rat incisor enamel organ using ruthenium hexammine trichloride.

Ruthenium hexammine trichloride (RHT) revealed granules of proteoglycans in the ground substance of the intercellular spaces of the outer enamel epithelium and stellate reticulum. Strong RHT-positive staining underlined the plasma membrane and filled the narrow intercellular spaces in a zone confined to the stratum intermedium and the basal part of the secretory ameloblasts. In the presecretory ameloblasts, this staining was either faint or absent. Its pattern suggests that proteoglycans and/or other groups of polyanions are functionally implicated in the transport and diffusion that allow delivery of metabolites near the basal part of the secretory ameloblasts.

Animals↗
PubMed1987

New muscle relaxants in outpatient anesthesiology.

The ideal neuromuscular blocking drug for dental and other outpatient procedures would be nondepolarizing (therefore reversible), highly potent, have a rapid onset and short duration of action, be highly specific for the nicotinic acetylcholine receptor, be eliminated independently of renal or hepatic metabolism, and have minimal side effects such as tachycardia and histamine release. The newer neuromuscular blocking drugs vecuronium and atracurium approach this ideal much more closely than the older drugs curare, metocurine, and gallamine. Aside from considerations of slightly higher cost, the neuromuscular blocking agents of choice remain succinylcholine for rapid, short-lived paralysis, vecuronium and atracurium for relaxation of 15- to 60-minute duration and when cardiovascular stability is vital, and pancuronium for longer surgical procedures. Vecuronium and atracurium have achieved and will continue to achieve predominance in the anesthetic management of the short-procedure patient.

Anesthesia, Dental↗
PubMed1987

Technique of successful lung transplantation in humans.

We have performed five single lung transplantations for end-stage pulmonary fibrosis, with four long-term survivors. Two patients underwent right lung transplantation and two underwent left lung transplantation. The procedure is performed with one lung anesthesia, although cardiopulmonary bypass is available on standby if required. Donor and recipient procedures are performed in adjacent operating rooms. On the basis of laboratory studies, a pedicle of omentum is wrapped around the bronchial anastomosis after its completion to restore bronchial artery circulation and protect the anastomosis. The four patients were discharge from the hospital within 4 to 6 weeks and three returned to normal employment at 3 months. Success in these cases is attributed to careful patient selection, use of cyclosporine, and use of an omental pedicle to protect and improve healing of the bronchial anastomosis.

Cyclosporins↗
PubMed1987

Simultaneous occurrence of chylothorax and subarachnoid pleural fistula after thoracotomy.

A left chylothorax complicated elective left posterolateral thoracotomy and emergency decompressive laminectomy carried out on a 32-year-old woman with a benign neurofibroma. Failure of conservative therapy necessitated ligation of the thoracic duct and this in turn unmasked the concomitant subarachnoid-pleural fistula. Surgical repair and lumbar subarachnoid drainage were required to close the second fistula. The clinical setting, diagnosis and management of this uncommon condition are reviewed.

Adult↗
PubMed1987

Extended cervical mediastinoscopy. A single staging procedure for bronchogenic carcinoma of the left upper lobe.

Despite a common misconception, bronchogenic carcinoma of the left upper lobe frequently metastasizes to lymph nodes not only in the anterior mediastinum (para-aortic and subaortic) but also in the superior mediastinum. Anterior (parasternal) mediastinotomy can be used to assess only the former compartment. This procedure alone, if not done in conjunction with standard cervical mediastinoscopy, will fail to disclose technically unresectable N2 or N3 disease of the left upper lobe involving the superior mediastinum. We have developed a technique to explore and sample nodes from both regions by extending a standard cervical mediastinoscopy, eliminating the need for a second incision when the anterior mediastinal compartment requires assessment. We have prospectively analyzed the first 100 procedures that we performed. This technique has been found to be accurate and exceptionally safe with one superficial wound infection as the only complication. We can recommend this single staging procedure for preoperative assessment of bronchogenic carcinomas of the left upper lobe.

Adult↗
PubMed1987

A prospective evaluation of magnetic resonance imaging, computed tomography, and mediastinoscopy in the preoperative assessment of mediastinal node status in bronchogenic carcinoma.

Computed tomography, magnetic resonance imaging, chest roentgenography, and mediastinoscopy were compared prospectively as staging modalities to assess mediastinal node status in 84 patients with presumed operable bronchogenic carcinoma. Computed tomography was associated with a sensitivity of 71.0%, a specificity of 87.7% and an overall accuracy of 82.1%. Magnetic resonance imaging did not provide any advantage over computed tomography in the assessment of mediastinal node status. The accuracy of computed tomography was not dependent on cell type of the primary tumor. Although chest roentgenography had a sensitivity of 80.7%, the overall accuracy of 57.1% was unacceptably low. The sensitivity (87.1%), specificity (100%), positive (100%) and negative (93.0%) predictive values, and accuracy (95.2%) of mediastinoscopy exceeded those observed with all other modalities. We continue to recommend mediastinoscopy as the most accurate staging investigation in the routine management of patients with bronchogenic carcinoma.

Carcinoma, Bronchogenic↗
PubMed1987

Wide local excision as an alternative treatment for periampullary carcinoma.

Wide excision of periampullary carcinoma is associated with low operative morbidity and mortality, but its effect on long-term survival, compared with that of pancreaticoduodenal resection, is controversial. Five patients with periampullary carcinoma were treated with wide local excision as a definitive procedure. There was no operative death, and four patients survived for two or more years following the operation. These patients are presented and the literature is reviewed.

Adenocarcinoma↗
PubMed1987

The effect of meperidine on the guinea pig extrahepatic biliary tract.

The effect of meperidine on the mechanical activity of isolated guinea pig common bile duct (CBD) and gallbladder was studied in vitro. The effect was found to consist of inhibitory and excitatory phases. The inhibitory phase, characterized by a decrease in the response of the CBD and gallbladder to carbachol and electrical stimulation, was seen with concentrations of 10(-6) M or higher. The excitatory phase, seen at high concentrations of meperidine (5 X 10(-5)-10(-4) M), involved an increase in spontaneous contractions of CBD and in the tone of the gallbladder. Neither effect of meperidine was affected by 0.5 X 10(-5) M naloxone. These data indicate that meperidine acts on the biliary tract by a mechanism different from that associated with the effect of morphine.

Animals↗
PubMed1986

Increased proliferative activity in selenium-deficient mouse liver.

Male albino NMRI mice were fed a selenium-deficient (Se-), torula yeast-based diet containing less than 10 ppb Se for at least 2 months (Se-) while a control group received the same diet supplemented (Se+) with 330 ppb Se as Na2SeO3. The Se-(-)animals showed multiple enzyme modulations of liver enzyme activities indicating that they were in a severely Se- state. No significant difference in the basic DNA synthesis rate of Se-(-)animals compared to Se+ controls was measured. However, when liver cell proliferation was induced by either hepatopoietin pretreatment or by partial hepatectomy, an about 3-fold increase in DNA replication rates was found in Se- compared to controls. We conclude that the enhanced proliferative activity in Se- mouse liver is expressed in an emergency situation.

Animals↗