Biomedical subjects
Publications and source records attributed to D C Baker.
It is axiomatic that nerve grafting be considered as an integral part of every ablative or traumatic injury involving the extratemporal main trunk and branches of the facial nerve. Our experience with 170 autogenous grafts has established the efficacy of the technique and has proved the high regenerative and adaptive capacities of the facial nerve system.
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A number of 5'-(O-acyl) derivatives of 9-beta-D-arabinofuranosyladenine (ara-A, VIRA-A) (2a-k) were prepared by direct acylation of the parent nucleoside 1 in pyridine-N,N-dimethyliformamide. These compounds, designed as prodrugs for 1, offer a range of solubilities and lipophilicities indicating for several examples improved solubility and the potential for improved membrane transport over 1. All are resistant to deactivation by adenosine deaminase. Of special interest is the 5'-(O-valeryl) derivative 2d that shows a marked increase in antiviral activity over 1.
The neurosurgical treatment of acromegaly is well established, but little has been written about correction of the facial deformities of this disease. Although hypertrophy of the skin and subcutaneous tissues may decrease after successful treatment of the pituitary tumor, there is no reversal of the bony changes. An acromegalic patient is presented whose facial deformities were repaired in stages by mandibular osteotomy and soft tissue excision. The history and pathology of acromegaly are reviewed.
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More men are undergoing rhytidectomy now. This operation is specifically different in the preoperative planning, the surgical procedure, the postoperative complications, and the final results (compared to rhytidectomy in females). Large hematomas occurred in our male patients more than twice as often as in females.
Although criticisms of the submucous resection of the nasal septum and turbinectomy have been given, this is not to discredit these procedures when they are truly indicated. Certainly there are anatomic deformities causing nasal obstruction wherein a submucous resection of the septum or a submucous resection of the anterior portion of the inferior turbinate would be of benefit. The surgeon performing rhinoplastic surgery must be aware of the physiologic causes of nasal obstruction. Often a combination of structural deformity and rhinitis is blocking the airway. Intranasal, intramucosal injections of long acting corticosteroids have proven to be of great benefit in the treatment of chronic allergic, vasomotor, and hypertrophic rhinitis, and they are a useful adjunct to rhinoplastic surgery.
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A microcolony technique has been demonstrated as being useful for the rapid determination of the viabilities of single cells of Myocbacterium fortuitum. Cultures of M. fortuitum grown to early logarithmic phase in broth were treated with the sputum digestant N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH) for periods of 10 to 40 s. After growth for three generations (7.5 h) on agar films, viabilities were determined by counting under a phase contrast microscope. The viable mycobacteria grew into microcolonies that exhibited extensive branching, whereas the nonviable mycobacteria remained as single cells. Sputum was mixed with some broth cultures before treatment to stimulate the digestion process in a clinical laboratory. When broth cultures were treated with sputum digestant for 40 s, only 2.8% of the cells remained viable. When the broth cultures were mixed in a ratio of 1:4 with sputum and then treated for 40 s, 16.4% of the cells remained viable. The results also indicate M. fortuitum is very sensitive to the digestant. The results also indicate that a microcolony technique could be used for the assessment of the viability of mycobacteria.
Acylated aldose dialkyl dithioacetals with bromine undergo replacement of one alkylthio group by bromine. These unstable bromides react, as by fusion with 2,4-bis(trimethylsilyloxy)pyrimidine, to give acylated 1-(pyrimidin-1-yl) derivatives that upon saponification afford acyclic sugar nucleoside analogues, some as separable mixtures of 1-epimers. Systemic stereochemical variants have been conducted. Pmr conformational studies show that the sugar chain is extended in certain examples, whereas others favor folded ("sickle") conformations, in line with a general rationale developed for acyclic-sugar derivatives. Condensation of the bromides with purines gives 9-substituted acyclic-sugar nucleoside analogues; synthesized systematically for various series, these include the D-pentoses in combination with 6-mercaptopurine. In vitro and in vivo biological activities vary according to stereochemistry of the sugar. The position of substitution of the sugar chain, the chirality at C-1', and the tautomeric form of the heterocycle, were established by x-ray crystallography of the product from D-arabinose and 6-mercaptopurine. The x-ray data permit correlation of C-1 chirality throughout the series and pmr data indicate the favored conformations.
Preparation of both a 5'-deuterium and a 5'-tritium-labeled 9-beta-D-arabinofuranosyladenine (6a and 6b) by reduction of the protected 5'-aldehyde 4 is described. Conversion of 6b to the 5'-tritium-labeled 5'-monophosphate 7b was effected directly with a phosphoryl chloride-formic acid reagent. The product 7b exhibited consistently higher blood levels of nonvolatile tritium than the 2-labeled compound when tested in dogs.
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