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Biomedical subjects

J D Phillips

Publications and source records attributed to J D Phillips.

8 recordsLinked to original sources

Deletion of subunit 9 of the Saccharomyces cerevisiae cytochrome bc1 complex specifically impairs electron transfer at the ubiquinol oxidase site (center P) in the bc1 complex.

Deletion of QCR9, the nuclear gene encoding subunit 9 of the mitochondrial cytochrome bc1 complex in Saccharomyces cerevisiae, results in inactivation of the bc1 complex and inability of the yeast to grow on non-fermentable carbon sources. The loss of bc1 complex activity is due to loss of electron transfer activity at the ubiquinol oxidase site (center P) in the complex. Electron transfer at the ubiquinone reductase site (center N), is unaffected by the loss of subunit 9, but the extent of cytochrome b reduction is diminished. This is the first instance in which a supernumerary polypeptide, lacking a redox prosthetic group, has been shown to be required for an electron transfer reaction within the cytochrome bc1 complex.

Cytochrome b Group

Fertility after simulated Fowler-Stephens orchiopexy in rats.

In order to determine the effects of the Fowler-Stephens orchiopexy (FSO) on fertility, young rats underwent simulated FSO, FSO and concurrent contralateral orchiectomy (FSO/OR), unilateral orchiectomy (OR), or sham operation (controls). Twelve weeks after the operation, each male rat was mated to two proven-fertile female rats for 17 days (three ovulatory cycles). Two weeks later, both male and female rats were killed. No pregnancy resulted from the matings of the FSO/OR males. In contrast, pregnancy ensued in 13 of 16 (81%) females in the FSO group, 9 of 14 (64%) in the OR group, and 11 of 12 (92%) in the control group. There were no fertile males in the FSO/OR group. In the FSO group, eight of eight males induced pregnancy in at least one female; in the OR group, six of seven (86%) males were fertile as were all six males in the control group. No differences in litter size or fetal weight were observed between fertile females in various groups.

Animals

Studies of louping-ill virus (Flavivirus group) in wild red grouse (Lagopus lagopus scoticus).

Studies were made to find evidence of louping-ill virus infection in free-living red grouse and relate this to their breeding success. In areas where ticks were abundant 61 (84%) adult grouse had antibody to the virus compared with 1 (10%) in areas where ticks were relatively scarce. Of 162 chicks tested 25 were shown to be viraemic. Infected chicks were of significantly less weight than comparably aged uninfected birds and the probability that they died was much greater than that of uninfected birds. It is concluded that the relatively poor breeding success in areas of high tick numbers was principally due to infection with louping-ill virus. The susceptibility of the red grouse to infection is discussed.

Animal Population Groups

A new coagulation defect associated with a case of melanomatosis.

A marked abnormality of the intrinsic coagulation system was observed in a patient with melanomatosis and frank melanuria. With successful treatment of the tumour there was a parallel improvement in the clotting abnormality. This defect was shown to be a deficiency of factor XI together with a previously unrecognised factor. This is distinct from either Fletcher or Fitzgerald factors and appears to act between factors XI and X in the coagulation sequence.

Adult

Prosthetic implications of Eagle's syndrome.

Eagle's syndrome can produce symptoms that may be easily confused with those resulting from wearing a prosthetic restoration. The symptoms resulting from elongated styloid processes and methods of diagnosis and treatment of these processes were described. A patient with Eagle's syndrome has been presented. The symptoms were initially suspected to be due to an ill-fitting mandibular removable partial denture. Further clinical and radiographic examination led to the diagnosis of Eagle's syndrome, and surgical correction was done. The prosthodontist should consider surgery as a possible treatment when the symptoms of the syndrome cannot be attributed to a prosthetic restoration. Various radiographic projections and panoramic radiography are valuable in confirming the presence of a calcified stylohyoid ligament or an elongated styloid process.

Carotid Artery Diseases