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Biomedical subjects

C R Brown

Publications and source records attributed to C R Brown.

12 recordsLinked to original sources
PubMed1978

Studies on ram acrosin. Activation of proacrosin accompanying the isolation of acrosin from spermatozoa, and purification of the enzyme by affinity chromatography.

1. A previously described, freeze-dried, partially purified ram acrosin preparation was fractionated on a column of Sepharose linked to the acrosin inhibitor p-(p'-aminophenoxypropoxy)benzamidine. Two acrosin fractions were obtained. 2. beta-Acrosin was homogeneous, quite stable at low pH and very stable when freeze-dried. Its molecular weight is about 38000, and it contains about six sugar residues per molecule, but no sialic acid. psi-Acrosin consisted of at least three unstable forms of acrosin. 3. When the entire purification process, starting from collection of semen, was carried out as rapidly as possible, the yield of beta-acrosin was increased and very little psi-acrosin was obtained. 4. In fresh ram semen the acrosin is present as the intra-acrosomal zymogen, proacrosin. After its extraction from spermatozoa autoproteolytic reactions convert proacrosin into beta-acrosin; psi-acrosin appears to be breakdown products of beta-acrosin. 5. When beta-acrosin was passed through a column of Sepharose linked to the non-inhibitory deamidinated analogue of the inhibitor it behaved as a hydrophobic protein. This is consistent with our view that acrosin (as zymogen) occurs in spermatozoa as a membrane-bound protein. 6. Success in the isolation of pure acrosin in high yield calls for an affinity adsorbent with the appropriate subsidiary hydrophobic properties.

Acrosin↗
PubMed1978

The activation of proacrosin in spermatozoa from ram bull and boar.

Acrosin activity was estimated in fractions from washed ram, bull and boar spermatozoa that had been disrupted using a Stansted Cell Disruptor. When p-aminobenzamidine was included in the medium during disruption, all the acrosin (acrosomal proteinase, EC 3.4.21.10) was recovered as its inactive zymogen form, proacrosin. But if spermatozoa were damaged before disruption, of were disrupted in the absence of p-aminobenzamidine, considerable amounts of active acrosin were detectable. It was concluded that conversion of proacrosin to acrosin takes place in spermatozoa only after the acrosome has been rutured. In a sucrose medium, all the proacrosin was bound to the sperm heads. Conversion to acrosin took place readily with all components in a bound state. Using arm sperm heads, the conversion was found to be relatively insensitive to pH, proceeding rapidly above pH 6.5; the rate of conversion was not affected by physiological levels of Ca2+, Mg2+, or Zn2+, although elevated ionic strength caused a solubilization of the acrosin activity and some slowing of the rate. Electrophoretic analysis revealed that several active forms of acrosin were involved, but the final product was a single stable form. Final levels of the active acrosin (expressed as mu mol N-alpha-benzoyl-L-arginine ethyl ester utilised/min per 10(9) heads) were: ram 26.2; bull, 15.9; boar, 133.8. But active site titration revealed that these different levels were not reflected in the numbers of active enzyme molecules on the sperm head; boar acrosin appears to be about three times more active towards benzoyl-arginine ethyl ester than do the acrosins from the other species.

Acrosin↗
PubMed1978

Enamel loss during orthodontic bonding and subsequent loss during removal of filled and unfilled adhesives.

1. The techniques required in the removal of highly filled composite adhesives at the end of orthodontic treatment on an average cause more loss of enamel than removal of an unfilled polymethylmethacrylate adhesive. 2. The amount of enamel lost during the removal of either adhesive may be of clinical significance because of the removal of a major part of the protective fluoride-rich layer of enamel. 3. The use of zirconium silicate on a rotating bristle brush may cause considerable abrasion of enamel.

Acid Etching, Dental↗
PubMed1978

The use of benzodiazepines in prison populations.

Experience with the use of tranquilizing drugs in the control of anxiety and in attempts at behavior modification, prompted a controlled study in the use of the benzodiazepines at the Utah state prison. It appeared that the benefits derived from the administration of these drugs in prisoner control were nearly outweighed by the frequent appearance of paradoxical rage reactions and increase in hostility and aggressive tendencies in these individuals. A double blind, cohort, prospective, randomized study was set up comparing Valium and Serax in their antianxiety qualities and their tendency to produce increased aggression and paradoxical rage reactions. Guidelines are proposed for the use of benzodiazepines and Serax is suggested as a superior drug to Valium for this purpose if indeed a tranquilizer of this type is indicated.

Aggression↗
PubMed1977

Dextroamphetamine with morphine for the treatment of postoperative pain.

In a double-blind, single-dose study, dextroamphetamine combined with morphine was compared with morphine alone to determine the relative efficacy of the combination given intramuscularly for postoperative pain. Each of 450 patients received one treatment of morphine sulfate (3, 6 or 12 mg) with dextroamphetamine (0, 5 or 10 mg). Analgesia, as measured by the patients' subjective responses to questions about relief of pain, was augmented when dextroamphetamine was given with morphine; the combination of dextroamphetamine, 10 mg, with morphine was twice as potent as morphine alone, and the combination with 5 mg was 1 1/2 times as potent as morphine. In simple performance tests, and in measures of side effects, dextroamphetamine generally offset undesirable effects of morphine (sedation and loss of alertness) while increasing analgesia. Effects on blood pressure, pulse and respiratory rate were minimal.

Adult↗
PubMedDate not supplied

Lorazepam compared with pentobarbital for nighttime sedation.

Lorazepam (0.5, 1, 2, and 4 mg) was compared with pentobarbital (60 and 180 mg) for its effect on sleep in "hospital insomnia." Subjective-response data were collected by research nurses. Lorazepam was found to be a potent nighttime sedative: 1 to 1.25 mg of lorazepam is equivalent to 100 mg sodium pentobarbital for measures of sleep quality and duration. At this dose level it is less effective than 100 mg of pentobarbital as a sleep inducer. Studies at higher doses (up to 4 mg) indicate that lorazepam has a wide therapeutic index.

Anti-Anxiety Agents↗
PubMedDate not supplied

Combined routes of administration to assay oral analgesia in postoperative pain.

To increase the sensitivity of the method for evaluating oral analgesics in postoperative patients, we designed a combined oral/parenteral bioassay. Drugs studied were parenteral morphine, parenteral propiram, and oral codeine at two dose levels each and oral propiram at four dose levels. Results from data on 308 patients suggest that future studies designed to establish the relative potencies of oral analgesics should use parenteral morphine as the standard in a combined oral/parenteral study because this approach provides a very sensitive measure of analgesia. Further, with one drug as the reference compound, results from many sources would be more readily compared.

Administration, Oral↗
PubMedDate not supplied

Phase I 1/2 evaluation and methodology of RO 20-2230 in postoperative patients.

This report presents the rationale and methodology of our "phase 1 1/2" model for drug evaluation and reports the results of a typical study. We found that Ro 20-2230, and investigational agonist-antagonist analgesic, was well tolerated in therapeutic doses, with 15 mg intramuscular Ro 20-2230 approximately equivalent to 10 mg intramuscular morphine sulfate.

Adult↗