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Biomedical subjects

R M Cook

Publications and source records attributed to R M Cook.

At least 73 records · Page 4Linked to original sources
PubMed1980

Residual complications in patients with major middle third facial fractures.

Residual complications associated with middle third facial fractures have been poorly documented in the literature. In the present study, 240 patients with fractures of the middle third of the facial skeleton, who were treated at the Royal Melbourne Hospital, Victoria, between 1969 and 1976, were reviewed to determine the residual complications of these fractures. Cranial complications were relatively uncommon, and 60 % of cases of cerebrospinal fluid rhinorrhoea ceased within 3 days of fracture reduction and fixation. Persistent infraorbital sensory defects occurred in 22 % of patients with Le Fort II or Le Fort III fractures. Orbital complications included diplopia, which remained in 8 % of cases, and was often corrected by secondary surgery. Residual complications involving the nose or maxillary sinus were uncommon (less than 5 %). Occlusal disharmony was present as a residual problem in 19.6 % of cases, although this could be managed by simple means in 89 % of these cases so that primary surgery and simple secondary dental procedures a satisfactory result in 98 % of all patients. The low incidence of dental complications is most likely a result of the rigid fixation employed in the fracture management, allowing accurate control of the bone fragments.

Brain Diseases↗
PubMed1980

Incidence and management of major middle third facial fractures at the Royal Melbourne Hospital. A retrospective study.

In a retrospective study of 240 patients with major fractures of the middle third of the facial skeleton, the incidence, anatomical patterns, and management of these fractures have been reviewed, and an assessment made of the concomitant injuries to other organs. Most of the fractures occurred in the 20-29-year age group (39%), and over 83% of the patients in this study were males. The most common cause of injury was road accidents (80.8% of all cases), and automobile occupants represented most of this group. The Le Fort II fracture was the most commonly sustained, and there were several variations from the classical fracture patterns recorded, combinations of fractures at different levels being frequent. Ninety percent of patients had another concomitant injury, indicating the need for multi-disciplinary care of this type of patient. The most common treatment method involved the use of craniomaxillary and intermaxillary fixation, which was usually maintained for 22-28 days.

Accidents, Occupational↗
PubMed1980

Effect of feeding isoacids with urea on growth and nutrient utilization by lactating cows.

In the growth study 10 g each of isobutyrate, isovalerate, 2-methylbutyrate, n-valerate, and phenylacetate were mixed with 80 g of urea, 50 g of molasses, and 270 g of ground hay and fed to nine dairy heifers for 90 days. The control group was fed the same diet minus isoacids and phenylacetate. All animals were fed ad libitum timothy hay as the sole roughage. In the digestion trial, two mixtures of isoacids and a control ration were fed to nine lactating cows in a 3 X 3 Latin square design with 28-day feeding periods. Corn silage was the sole roughage, and concentrate was fed in proportion to milk production. Collection of feces and urine was for the last 5 days of each period. Mixture 1 of isoacids contained on a molar basis 28, 24, 24, and 24% of isobutyrate, isovalerate, 2-methylbutyrate, and n-valerate, respectively. Corresponding for mixture 2 were 36, 17, 17, and 30%. Addition of isoacids increased growth rate of younger animals but not older ones. The isoacid mixtures improved utilization of nitrogen by lactating cows. Urinary nitrogen decreased, and retention of absorbed nitrogen increased. Digestibility of dry matter and nitrogen were not affected by isoacid additions.

Animals↗
PubMed1980

Spontaneous cytotoxicity of murine cells treated with the interferon inducers BRL 5907 and BRL 10739.

The effects of the polyribonucleotide interferon inducers, BRL 5907 and BRL 10739, on the spontaneous cytotoxicity of CBA mouse cells towards the allogeneic lymphoma EL-4, were investigated. Intravenous administration of BRL 5907 and BRL 10739 increased the cytotoxic activity of a non-adherent, theta-negative, surface immunoglobulin-negative cell present in the spleen, but had no effect on cells in the lymph nodes. Spleen cell cytotoxicity was established within 24 h of injection of the polyribonucleotides, but had disappeared by 4 days. In addition, injection of mice with BRL 10739 increased the spontaneous cytotoxicity of a nylon-wool-adherent, theta-positive spleen cell. Intraperitoneal injection of mice with BRL 5907 and BRL 10739 also enhanced the cytotoxic activity of a non-adherent peritoneal exudate cell.

Animals↗
PubMed1978

Spatial requirements between haptenic and carrier determinants for T-dependent antibody responses.

To gauge the proximity between cooperating T and B cells required for effective triggering of antibody production, guinea pigs were immunized with bifunctional antigens in which the haptenic and carrier determinants were separated by rigid spacers of varied dimension. These took the form 2,4-dinitrophenol-(proline)n-L-tyrosine-p-azobenzenearsonate, where n varied from 1 to 40 proline residues. Animals immunized with n = 10 and n = 22 compounds made strong anti-DNP antibody responses, whereas animals immunized with bifunctional compounds containing longer spacers did not make antibody detectable by precipitation. It can be calculated on the basis of very strong physicochemical evidence for the rigidity and axial translation of poly-L-proline chains in solution that the cut-off point for effective interaction between T and B cells lies between 69 and 97 A U.

Animals↗
PubMed1978

Distribution and kinetics of PBB residues in cattle.

Cows fed a constant amount of polybrominated biphenyl (PBB) reached a steady-state concentration in milk fat within 30 days. This concentration was approximately four times the concentration in the total diet. When feeding of PBB was stopped, the concentration in milk was adequately described as a sum of two first-order elimination rates. Biological half-life in environmentally contaminated cows, studied for 6 months about a year after contamination, was 60 days. The stage of lactation affected the rate of elimination, and in some concentrations increased shortly after calving. Residues were distributed in body tissues proportionally to concentration of fat in the tissues. Liver and brain were exceptions. Concentration in liver fat was generally higher than other tissues and possibly related to the treatment of some cows with phenobarbital. Residues in brain fat were significantly lower than all other tissues. The ratio of the concentrations in milk fat to concentration of residues in the blood of calves and fat of fetal tissues to the concentration in the corresponding tissue in the dams was 0.36:1. It was estimated that people consuming milk from the highly contaminated Michigan cows could have received PBB doses as great as 10 g from this source alone.

Animal Feed↗
PubMed1978

Effects of activated carbon, phenobarbital, and vitamins A, D, and E on polybrominated biphenyl excretion in cows.

Twelve cows environmentally contaminated with polybrominated biphenyl residues were in a balanced two-period changeover experiment. The treatments were activated carbon and sodium phenobarbital; sodium phenobarbital and injections of vitamins A, D, and E; activated carbon, phenobarbital, and vitamins A, D, and E; and control. A standard roughage and concentrate diet was fed. Average initial concentrations of polybrominated biphenyls in the milk fat ranged from 92 to 236 ppm. The experimental treatments did not affect significantly excretion of polybrominated biphenyls in milk and feces or the apparent half-life of residues in milk fat averaged 60 days but ranged from 36 to 301 days. The longer half-life in early lactation than in later lactation indicated an effect of change of body weight on half-life. Milk was the major route of excretion, averaging 6.5 times that of fecal excretion. Polybrominated biphenyl in milk fat, body fat, blood, and feces followed parallel concentrations troughout the study.

Adipose Tissue↗
PubMed1977

Behavioral role of the sexcombs in Drosophila melanogaster and Drosophila simulans.

The sexcombs were amputated from males of three strains of Drosophila melanogaster and one strain of D. simulans in order to assess the importance of these structures in the sexual behavior of these species. In D. melanogaster the sexcombs are important in attempts to copulate with the female. Their removal delays copulation but does not suppress it entirely. Other aspects of courtship are not influenced by removal of the sexcombs. Strain differences in quanitative aspects of courtship were found, and also in the insemination rates of females by males without sexcombs. The present evidence suggests that the sexcombs are primarily structures adapted to grasping the female securely during the act of intromission.

Animals↗
PubMed1977

Phenylthiocarbamide (PTC) taste sensitivity in selected populations of the Isle of Man and Cumbria.

PTC taste thresholds were determined using a modification of the Harris and Kalmus sorting technique for 854 Cumbrian schoolchildren and 699 individuals from the Isle of Man. A non-taster frequency of 19.7 percent was observed in the Cumbrian sample compared with a frequency of 27.8 per cent in that from the Isle of Man. Analysis of taste threshold distributions revealed significant variability, both within and between these two samples. Evidence of significant regional heterogeneity was detected in Cumbria but not in the Isle of Man. Finally, these two series were compared with data from neighbouring regions of the British Isles and Scandinavian populations.

Adolescent↗