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Biomedical subjects

S J Robinson

Publications and source records attributed to S J Robinson.

At least 55 records · Page 3Linked to original sources
PubMed1977

Inhibition of chloroplast electron transport reactions by trifluralin and diallate.

The herbicides trifluralin (alpha,alpha,alpha-trifluoro-2,6-dinitro-N, N-dipropyl-p-toluidine) and diallate (S-[2,3-dichloroallyl] diisopropylthiocarbamate) inhibit electron transport, ATP synthesis, and cytochrome f reduction by isolated spinach (Spinacia oleracea L.) chloroplasts. Both compounds inhibit noncyclic electron transport from H(2)O to ferricyanide more than 90% in coupled chloroplasts at concentrations less than 50 mum. Neither herbicide inhibits electron transport in assays utilizing only photosystem I activity, and the photosystem II reaction elicited by addition of oxidized p-phenylenediamine or 2,5-dimethylquinone is only partially inhibited by herbicide concentrations which block electron flow from H(2)O to ferricyanide. Inhibition of ATP synthesis parallels inhibition of electron flow in all noncyclic assay systems, and cyclic ATP synthesis catalyzed by either diaminodurene or phenazine metho-sulfate is susceptible to inhibition by both herbicides. These results indicate that trifluralin and diallate both inhibit electron flow in isolated chloroplasts at a point in the electron transport chain between the two photosystems.

Journal Article↗
PubMed1976

Surgical management of severe aortic coarctation and interrupted aortic arch in neonates.

Forty-four infants, 2 to 90 days of age, with severe obstructive lesions of the aortic arch, underwent emergency surgical correction between Jan. 1, 1966, and April 1, 1975. The typical clinical presentation was severe congestive heart failure and acidemia. Resection of an aortic coarctation with end-to-end anastomosis was performed in 31 patients. Eight (26 per cent) died after the operation. Since 1969, the mortality rate has been reduced to 14 per cent (3 of 22 patients) even though the incidence of major associated cardiac lesions has remained essentially constant (56 per cent from 1966 through 1969, 64 per cent from 1970 through March, 1975). This suggests that the higher survival rate has resulted from improved surgical techniques and postoperative care. The mortality rate in the infants operated upon during the second and third months of life was twice as high as that in those operated upon before the age of 1 month. Eight patients with Type A interrupted aortic arch were operated upon and 5 survived. Five patients with Type B aortic arch were operated upon and 3 survived.

Aorta↗
PubMed1976

Pulmonary artery conduits in infants younger than six months of age.

Ten infants under 6 months of age with right ventricular-pulmonary artery discontinuity have undergone reparative operations. Five infants had either Type I or Type II truncus and 5 had pulmonary atersia with some discontinuity between right and left pulmonary arteries. There have been 4 survivors in each group. The one death in each category was due to pulmonary hypertension. The remaining 8 patients have low pulmonary vascular resistance. The survival rate after the reparative technique in infancy appears better than that with other forms of palliative treatment, such as banding of shunts, in these severly ill patients.

Angiocardiography↗
PubMed1969

Sex differences in verbal and performance IQ's of children undergoing open-heart surgery.

Boys with congenital heart defects had essentially normal Verbal and Performnance IQ's on preoperative and postoperative tests; but girls' Verbal IQ's were significantly lower than those of boys, and significantly lower than girls' own Performance IQ's. This sex difference among congenital heart cases reverses the usual finding that girls excel on Verbal tests.

Adolescent↗
PubMedDate not supplied

Organization and transcription of genes important in Anabaena heterocyst differentiation.

The structural genes for nitrogenase and nitrogenase reductase have been cloned from Anabaena and physically mapped. The map differs from that of Klebsiella in several ways, including the insertion of 11 kbp between nifK and nifD in Anabaena. One nif RNA transcript has been studied in detail and shown to originate from a site in the Anabaena chromosome which lacks good correspondence with a typical prokaryotic strong promoter, suggesting the possibility of a need for positive activation. The nifH message is unstable or repressed or both under aerobic conditions. This feature is sufficient to account for the need for heterocyst differentiation in order for Anabaena to fix nitrogen aerobically. Structural genes for glutamine synthetase and the large subunit of RuBP carboxylase were also cloned, mapped and used to study transcription. In each case, the level of messenger RNA following nitrogenase induction is consistent with regulation of these genes at the level of transcription.

Chromosome Mapping↗
PubMedDate not supplied

Rearrangement of nitrogen fixation genes during heterocyst differentiation in the cyanobacterium Anabaena.

Nitrogen fixation by the cyanobacterium Anabaena is carried out in heterocysts, specialized, non-dividing cells which differentiate under conditions of ammonia or nitrate deprivation. In Anabaena, heterocyst differentiation is accompanied by rearrangement of some nitrogen fixation genes. A site-specific recombination between an 11 base-pair direct repeat sequence flanking the nifK and nifD genes removes 11 kilobases of intervening DNA, resulting in juxtaposition of the two genes and an alteration of the nifD protein-coding sequence.

Cell Differentiation↗