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Biomedical subjects

M Bacon

Publications and source records attributed to M Bacon.

36 records · Page 2Linked to original sources
PubMed1984

A monoclonal antibody to an antigen present on the microvillous membrane of the trophectoderm of the preimplantation blastocyst of the pig.

Immunization of BALB/c mice with 14-day pig preimplantation blastocyst material followed by fusion of spleen cells with NS-0 myeloma cells resulted in a clone, SN 1/38, which secreted IgG1 which reacted specifically with the microvillous border of the pig trophectoderm and trophoblast as assessed by immunohistology. SN 1/38 did not react with other fetal tissues, or with blastocysts from other animal species. It was shown by absorption studies and by enzyme-linked immunoabsorbent assay that SN 1/38 was not directed against the placental form of pig alkaline phosphatase. The location of this antigen and its apparent presence throughout gestation indicate a functional role in the materno-fetal interaction.

Animals↗
PubMed1980

A neurochemical and immunocytochemical study of P2 protein in human and bovine nervous systems.

The anatomical distribution of P2 protein was studied in human autopsy tissue. Spinal cord (SC) and peripheral nerve (PN) were stained by the peroxidase-antiperoxidase method with antisera to bovine P2, glial fibrillary acidic protein, and myelin basic protein (BP). P2 antiserum did not stain all of the myelin in the PN. The staining was randomly distributed and discontinuous along a given myelinated axon. P2 antiserum also stained SC myelin in a pattern similar to the PN. Only a fraction of the sheaths stained, in contrast to BP antiserum that stained all myelin sheaths in both the SC and PN. P2-positive myelin was distributed throughout the SC white matter, including an occasional myelinated fiber in the SC grey matter. P2 and BP antisera did not stain regions of demyelination in a case of idiopathic polyneuritis, while adjacent myelinated PN stained normally. Absorption of the P2 antiserum with P2, bovine PN or bovine SC (carefully dissected to eliminate PN contamination) nullified the specific staining in both the PN and SC; however, absorption with BP or hemispheric myelin did not eliminate P2 staining. The P2 antiserum formed a single immunodiffusion line with pure P2 and acid extracts of bovine SC and PN myelin, but not with an acid extract of bovine hemispheric myelin. Electrophoresis of defatted bovine SC produced a distinct band corresponding to P2. Therefore, three lines of evidence, immunocytochemical, immunodiffusion and electrophoretic, suggest that P2 is present in PN and SC but not in hemispheric myelin.

Animals↗
PubMed1976

Spectrographic comparison of two types of spastic dysphonia.

A spectrographic comparison of the voices of two patients with spastic dysphonia demonstrated differences in vocal characteristics. The voice of one patient was characterized by intermittent breathiness which appeared spectrographically as a breakdown in formant structure or as the addition of fricative fill superimposed upon resonance bars. The voice of the second patient was characterized by strain-strangle phonation which appeared spectrographically as widely and irregularly spaced vertical striations. The contrasting vocal characteristics of the two patients are compatible with the viewpoint that there may be two types of spastic dysphonia.

Aphonia↗
PubMed1976

Interaction between the effects of spinal heating and cooling and of injections into a lateral cerebral ventricle of noradrenaline, 5-hydroxytryptamine and carbachol on thermoregulation in sheep.

1. A study has been made of the interactions of the thermoregulatory effects of spinal cord heating and cooling and of the injections into the cerebral ventricle of noradrenaline, 5-hydroxytryptamine (5-HT) and carbamylcholine in sheep. 2. The interactions of spinal cord heating and the injections into the cerebral ventricle of noradrenaline, 5-HT and carbamylcholine were very similar to those of hypothalamic heating or of high ambient temperature and the injections into the cerebral ventricle of these substances. These results are interpreted as evidence of the synaptic convergence of the pathways from peripheral, spinal cord and hypothalamic warm-sensors at or before the points of action of these synaptically active substances. 3. The only definite thermoregulatory effect of spinal cooling was the onset of shivering which could be due to a purely spinal effect of cold. No substantial evidence was obtained of an interaction between spinal cooling and an injection of noradrenaline, 5-HT or carbamylcholine into the cerebral ventricle. Thus there was no clear indication of centripetal pathways from spinal cold sensors converging with those from the skin and the hypothalamus for which evidence of convergence was obtained in an earlier study. 4. The results of this study are expressed in terms of the neuronal model of Bligh, Cottle & Maskrey (1971) and Maskrey & Bligh (1971), appropriately modified.

Animals↗
PubMed1975

Speech changes in Parkinson's disease during treatment with L-dopa.

The speech of 17 Parkinsonian patients was evaluated before and after the administration of L-DOPA therapy. A significant difference was demonstrated after treatment for voice quality, articulation, and pitch variation, but not for rate of speech. Amount of speech improvement correlated significantly with amount of physical improvement. Although age and duration of disease may exert some influence on speech change, the results suggest that these factors do not reliably predict the response. After 4 years of L-DOPA therapy, three out of four patients demonstrated additional improvement or the same degree of speech improvement.

Levodopa↗
PubMed1975

Neural antigens and induction of myelination inhibition factor.

Rabbits were sensitized or immunized with a variety of central nervous system antigens, including bovine spinal cord, bovine, monkey, human, guinea pig, rabbit and rat S myelin basic proteins, and a polypeptide derived from guinea pig basic protein. The animals were observed for development of experimental allergic encephalomyelitis, and their sera were collected at varying intervals after inoculation and evaluated for presence of precipitating anti-basic protein antibody and for their ability to inhibit myelin formation in cerebellar tissue cultures. The resulting complete dissociation between development of experimental allergic encephalomyelitis, the presence of anti-basic protein antibody and the occurrence of myelination inhibition factor suggests that myelination inhibition factor is not involved in the pathogenesis of experimental allergic encephalomyelitis, and argues against a role for anti-basic protein antibody as an antimyelin factor in vitro.

Animals↗
PubMedDate not supplied

A comparison of the incidence, duration, and degree of the neurologic toxicities of cisplatin-paclitaxel (PT) and cisplatin-cyclophosphamide (PC).

Logically, the choice of any ultimate optimum therapy requires, as well as comparison of the survival outcomes, a comparison of both subjective and objective toxicities in terms of incidence, degree of severity, and duration. Frequently such detail is not collected in large studies. Both cisplatin and paclitaxel are effective but neurotoxic drugs for ovarian cancer. The optimum choice is further complicated in that carboplatin is a possible alternative for cisplatin, being less neurotoxic but having greater hematologic toxicity. Similarly, 3-h and 24-h infusion schedules of paclitaxel have different incidences in opposite directions of hematologic and neurologic toxicities. One hundred fifty two eligible Canadian patients entered in a European-Canadian study that compared paclitaxel-cisplatin (PT, 79) patients with cyclophosphamide-cisplatin (PC, 73 patients) had both subjective and objective neurotoxicity data collected from treatment initiation to disease progression. Incidence, degree, and duration (compared in an analogous way to remission durations) of neurotoxicity were compared in the two arms to quantify the additional paclitaxel toxicity. No significant differences were found for motor toxicity, motor impairment, hearing impairment, or insomnia. For sensory changes during treatment, toxicity (all grades, 91% vs. 49%; grade 3 or higher, 29% vs. 3%) incidence, subjective impairment (a little or more, 89% vs. 40%; lots, 54% vs. 11%) incidence, and toxicity duration (all grades only), and impairment durations (both degrees) were all worse for PT. During follow-up, only the incidence of all-grade sensory toxicity was worse and this was not reflected by any other parameters. We conclude that paclitaxel adds considerably, but only temporarily, to the sensoy neurotoxicity of cisplatin.

Adult↗
PubMedDate not supplied

Effect of the Passy-Muir tracheostomy speaking valve on pulmonary aspiration in adults.

PURPOSE: We determined instances of aspiration in adults with tracheostomies and investigated the effect of the Passy-Muir tracheostomy speaking valve on occurrences of aspiration. METHODS: Adults with tracheostomies scheduled for videofluoroscopic swallowing examinations who met inclusion criteria were enrolled. According to study protocol, 6 presentations of thin liquids were recorded, 3 with and 3 without the Passy-Muir tracheostomy speaking valve. If a cuffed tube was present, the cuff was deflated fully for all presentations. RESULTS: Seven of 15 subjects aspirated material on 1 or more presentations of thin liquid. Five subjects aspirated material only with the Passy-Muir tracheostomy speaking valve off, whereas 2 subjects aspirated material with and without the valve. No subject aspirated material while the valve was on exclusively. Aspiration was significantly less frequent with the Passy-Muir tracheostomy speaking valve on than with it off. CONCLUSIONS: Clinically unapparent aspiration occurs commonly in patients with tracheostomies. An expiratory occlusive valve can reduce, though not eliminate, occurrences of aspiration. CLINICAL IMPLICATION: The benefit of the Passy-Muir tracheostomy speaking valve should be evaluated in selected patients who aspirate liquid.

Adult↗
PubMedDate not supplied

Long-term follow-up confirms a survival advantage of the paclitaxel-cisplatin regimen over the cyclophosphamide-cisplatin combination in advanced ovarian cancer.

Two independent and consecutive randomized clinical trials, conducted by the American Gynecological Oncology Group and by an European-Canadian Intergroup, have shown superiority, in clinical response rate, progression-free survival, and overall survival, of a cisplatin-paclitaxel regimen over cisplatin-cyclophosphamide given as first-line chemotherapy for women with advanced epithelial ovarian cancer. The results of these studies, published with a median follow-up of about 3 years, have been updated with a 6.5-year follow-up: In each case, an 11% absolute gain in survival favoring the paclitaxel arm is shown; this advantage remains both statistically and clinically significant and supports a role for paclitaxel in frontline chemotherapy for advanced ovarian cancer.

Antineoplastic Combined Chemotherapy Protocols↗