Biomedical subjects
Publications and source records attributed to M Goldberg.
Samples of carious human teeth treated in vitro for 48-92 hours with a bacterial Achromobacter collagenase in solution in borate buffer at 33 degrees were examined with the scanning electron microscope. The enzyme was seen to destroy soft carious dentine but not sound layers of dentine beneath the lesion. This finding may have clinical implications.
Rat incisor odontoblasts and predentine fixed with tannic acid-glutaraldehyde-osmium tetroxide (Tago) were compared with those obtained by prior incubation in tannic acid-Ringer before conventional fixation with glutaraldehyde-osmium-tetroxide (Tari) The Tago method allowed visualization of complex glycoconjugates along the plasma membrane, in the pericellular spaces and in the intercellular predentine matrix. The non-collagenous proteins, proteoglycans and lipids were seen as granules and thin filaments located between the collagen fibers and at their surface. The collagen fibers themselves were also stained. The Tari method which was used to visualize exocytosis, mainly revealed endocytosis in the form of large intracellular vacuoles containing tannic acid and stained proteoglycans. It is suggested that tannic acid-Ringer incubation prior to fixation increases the endocytosis of the matrix components, which acculumates in these large vesicles.
Preparation of the cavo-surface margin for fillings with "composites resins" is an important operative step. The good peripheral fit of the restoration and the stability of the bond between tooth and material depend on that preparation. How should the "bevel" be shaped? Scan electron microscopy of long bevels and rounded bevels show that the former seem more favorable to the fit of the filling. The section of enamel prisms is clean. The aprismatic surface area disappears. This enables to etch the cristallites in a more favorable axis as opposed to the rounded bevel.
Otolaryngologists are well aware of the potentially devastating consequences of inhaling a sharp foreign body. We report here a case of a laryngectomized patient who accidentally inhaled a safety pin through his tracheal stoma under highly unusual circumstances. This proved to be a life-threatening situation which resolved only after a complicated hospital admission culminating in a thoracotomy. We use this case to suggest guidelines that otolaryngologists may wish to discuss with their laryngectomized patients with regard to stomal care.
To determine the current operative morbidity for elective surgery of lung cancer, the authors reviewed the charts of 1076 consecutive patients who underwent pulmonary resection between 1978 and 1984 at two major Canadian teaching hospitals. Of these patients, 731 (68%) had a normal course. Minor complications occurred in 206 patients (19%); the majority were supraventricular arrhythmias (100 events) and atelectasis (41 events). Nonfatal major complications occurred in 105 patients (9.8%). The overall operative death rate was 3.2%. If supraventricular arrhythmias are excluded, nearly 80% of patients had a smooth postoperative course. In order to correlate the occurrence of complications with pre- and perioperative data, several possible risk factors were analysed. For major complications and death, the age, the forced expiratory volume, weight loss, coexisting disease, stage of cancer and extent of resection were significant risk factors (p less than 0.05). The data show that elective pulmonary surgery can be done safely and complications prevented. The necessary requirements are: proper selection of patients, a well-performed operation and prompt treatment of potential problems.
Ninety-four strains of coagulase positive staphylococci and 73 strains of coagulase negative staphylococci were tested for their susceptibility to methicillin, using agar dilution and disc diffusion techniques with Diagnostic Sensitivity Test agar (DST) and DST supplemented with salt, incubated at 30 degrees C and 37 degrees C. Disc diffusion on salt-incorporated DST at 30 degrees C was most reliable for detecting methicillin resistance in both types of staphylococci. The agar dilution methods were particularly poor for detecting resistance with coagulase negative staphylococci. The simultaneous testing of coagulase positive and negative staphylococci by this method indicated the need for both DST and salt-incorporated DST agar plates, incubated at 30 degrees C. However, sensitive strains should still be tested by disc diffusion for confirmation.
Between 1981 and 1988, 41 patients underwent pharyngolaryngoesophagectomy with transhiatal gastric transposition and primary pharyngogastrostomy for hypopharyngeal, laryngeal, and cervical esophageal carcinoma. All patients had squamous cell carcinoma. Twenty-one patients had been treated initially by high-dose radiotherapy, but the tumor had either persisted or recurred. Four patients had previously received high-dose local radiotherapy to the neck for unrelated diseases, and in 16 patients no preoperative radiotherapy was given. There was one operative death. Anastomotic leaks developed in nine previously irradiated patients and three required flap reconstructions. Thirty patients had satisfactory swallowing postoperatively and three swallowed poorly. Delayed gastric emptying was a serious problem in two patients, necessitating pyloric bag dilatation in one and pyloroplasty in another. The average postoperative stay was 31 days. Thirty-seven percent survived longer than 12 months and 15% longer than 24 months. The probability of survival after 2 years is 35%. All deaths from recurrent disease occurred within 412 days postoperatively. At present, pharyngolaryngoesophagectomy with gastric transposition and primary pharyngogastric anastomosis offers the best chance for cure or palliation with acceptable morbidity and function for selected patients with advanced hypopharyngeal and laryngeal tumors.
Ester synthesis from aliphatic monoalcohols and organic acids was investigated by using a microbial lipase. The reaction medium only contained the substrates and the enzyme without addition of water or organic solvent. During the reaction, water was produced and the water activity (aw) increased. Batch reactors and continuous-flow reactors were used. In batch, the aw was 0.13 at the beginning of the reaction and increased to reach a plateau at 0.77, after which ester synthesis continued without modification of the aw. Different alcohols and acids were tried in solid-liquid reactors, and all cases synthesis occurred, leading to a significant increase in the water activity. For continuous-flow reactors, the use of silica beads retaining water inside the reactor where the enzymatic reaction took place resulted in some control of the enzymatic reaction by changing the aw.
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Developing rat incisors were treated with malachite green-aldehyde fixative solution (MGA), which retains and stains lipids. We observed positive staining occurring as dots in the basement membrane. Most of these dots (2-3.5 nm in diameter) were grouped in the lamina densa but some were also present in the lamina lucida and the lamina fibroreticularis. These data provide evidence for the existence of lipids in the dental basement membrane and suggest that they are distributed together with the various groups of proteins so far detected.
Lung transplantation has become a successful method in the therapy for end-stage pulmonary disease. While single-lung transplantation provides benefit to patients with pulmonary fibrosis, bilateral lung transplants are required for septic or emphysematous lung disease. We describe the technique employed in 6 patients to transplant en bloc both lungs with the recipient heart left in place. The lungs are connected by a left atrial cuff, main pulmonary artery, and trachea. The completed implantation has a tracheal anastomosis securely wrapped in omentum, a left atrial anastomosis posterior to the heart, and a pulmonary artery anastomosis anteriorly. Airway ischemia resulted in the death of 1 patient. This procedure allows complete excision of all diseased pulmonary tissue, retention of the recipient's own heart, and separate excision of the donor heart for use in another recipient, thereby markedly increasing the supply of donor lungs for transplantation.
The scarcity of multiple-organ donors for perfused organ transplantation requires cooperation between various transplanting teams to maximize organ retrieval. We have developed a technique for the extraction of a cardiac and separate pulmonary graft from the same donor. These grafts can then be successfully implanted into two separate recipients. Our experience with 9 successful extractions and implantations is recorded.
Spontaneous localized perforation of the gastrointestinal tract, unrelated to mechanical intestinal obstruction and with no evidence of necrotizing entrocolitis (NEC), occurred in 20 neonates. Three perforations were located in the stomach, 11 in the small intestine, and six in the colon. Maternal obstetric complications as well as prematurity and postnatal distress were common in these patients. The overall survival rate was 80%. There was no late gastrointestinal symptoms in the survivors. Whether idiopathic perforation of the gastrointestinal tract results from a localized form of NEC or from a distinct lesion of unknown etiology has not yet been ascertained. Some ideas concerning the etiology of this entity, as well as some diagnostic aspects are discussed.