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Biomedical subjects

V Marshall

Publications and source records attributed to V Marshall.

At least 55 records · Page 3Linked to original sources

Evaluation of renal preservation using the isolated perfused rat kidney. Ischaemic damage and the effects of inosine.

An isolated perfused rat kidney has been used to determine the response to prolonged warm ischaemia and to examine renal preservation procedures. All measurements of function declined to near zero after 90 min of warm ischaemia. Measurement of total sodium reabsorption (TNa) was the most sensitive indicator of renal damage. Inosine was without effect on subsequent renal function after 60 or 90 min of warm ischaemia, or after 24 hr of cold ischaemia. Surface cooling or hypertonic citrate solution, in the cold or at 37 degrees C, significantly improved renal function, and their use in clinical renal preservation rather than that of inosine was supported by the present results.

Adenosine Triphosphate↗

Complications of intravenous therapy: reduction by buffering of intravenous fluid preparation.

Local complicationn of intravenous infusions have become a common cause of morbidity in hospitals. Two consecutive groups of patients were studied: the patients in the first group had received standard non-buffered intravenous fluid preparations with pH from 3.6 to 6.0; the second group of patients received fluids which were buffered to a neutral pH. The incidence of local complications in the first group was high (58%), with phlebitis being the most common complication which occurred in 43% of patients. The addition of a buffer to the fluids just before the infusion reduced the incidence of all complications in the second group of patients to 28%, and that of phlebitis to 19%. It will be shown that the complications can be significantly reduced by buffering the infusion fluids.

Bacteria↗

Cytochrome P450cam and its complexes. Mössbauer parameters of the heme iron.

Mössbauer spectroscopy has been used to study the heme iron in various states of cytochrome P450cam from the camphor-hydroxylating system of the bacterium Pseudomonas putida. Native, camphor-free P450cam contains low-spin ferric iron, part of which (approx. 50-70%) is converted to the high-spin ferric state upon addition of camphor. The Mössbauer spectra of the camphor-free enzyme (S equals 1/2) and of the high-spin component (S equals 5/2) of the camphor complex have been successfully simulated using a model based on crystal-field theory and simple convalency considerations. The native low-spin ferric state of P450cam forms a complex with 2-phenylimidazole, with small changes in the g values and Mössbauer spectra. These changes can be accounted for consistently in the crystal-field model referred to above. The addition of putidaredoxin to the camphor-complexed, oxidized P450cam decreases the intensity of the high-spin component and changes its quadrupole splitting. The reduced form of P450cam contrins high-spin ferrous iron, both in the presence and absence of camphor. The complex of reduced P450cam with molecular oxygen is diamagnetic and has a combination of quadrupole splitting and isomer shift that is unusual for a ferrous complex, but strongly resembles that of oxyhemoglobin. These results are compatible with the bound superoxide, Fe3+-O-2, model proposed for oxyhemoglobin (Weiss, J. J. (1964) Nature 202, 83-84). Reduced P450cam and its complexes, oxyP450cam-CO, are all found to be analogous in some respects to the corresponding hemoglobin complexes.

Binding Sites↗

Ureteral pressure flow studies in difficult diagnostic problems.

Before a ureteral operation is undertaken for dilated, non-refluxing ureters it is essential to determine whether obstruction is present, since an operation is unnecessary and can be hazardous if there is no obstruction or infection. Obstruction is most accurately diagnosed by perfusing the upper tract at a known flow rate and measuring the resulting pressure. This test was performed on 5 patients in whom there was doubt as to the presence of obstruction from the radiographic evidence. In 4 of the 5 patients low pressure was found, the obstruction was excluded and an operation was avoided. In the fifth patient the obstruction was confirmed and relieved. The pressure flow test is useful in the diagnosis or exclusion of obstruction in the upper urinary tract.

Adult↗

Is urography necessary for patients with acute retention of urine before prostatectomy?

In 180 urograms performed on 203 patients admitted to hospital with acute or acute-on-chronic retention of urine 38 abnormalities were noted, most of them being related to upper tract obstruction. Of 4 diverticula detected only one needed treatment. Waiting for the urogram imposed an extra delay of more than 3 days between admission and operation and an equal prolongation of the whole hospital stay. There appears to be no justification for routine urography prior to prostatectomy in the patient admitted with urinary retention.

Cystoscopy↗

The natural history of renal and ureteric calculi.

In a prolonged follow-up of a series of 416 patients at The London Hospital Stone Clinic it was found that recurrence could still occur even as long as 10 years after the first stone, though this risk decrease slowly year by year. Recurrence is seldom related to hypercalciuria or urinary infection except when infection is caused by or associated with B. proteus in women. Claims for the value of any form of therapy for stone disease must be evaluated against the background of the natural history of lithiasis.

Adolescent↗

The residual renal stone.

A study of the observer error built in to contact preoperative radiography for renal stones shows that particles less than 2 mm in diameter are likely to be missed. The radiographic follow-up of 100 patients from whom 120 large staghorn calculi have been removed over a period of up to 10 years shows that new calculi may form in kidneys which have been completely cleared, and that residual stones do not always grow, but equally often pass spontaneously, or remain unchanged.

Female↗

Antibacterial activity of the lactoperoxidase system in milk against pseudomonads and other gram-negative bacteria.

Products of thiocyanate oxidation by lactoperoxidase inhibit gram-positive bacteria that produce peroxide. We found these products to be bactericidal for such gram-negative bacteria as Pseudomonas species and Escherichia coli, provided peroxide is supplied exogenously by glucose oxidase and glucose. By the use of immobilized glucose oxidase the bacterial agent was shown to be dialyzable, destroyed by heat and counteracted, or destroyed by reducing agents. Because the system is active against a number of gram-negative bacteria isolated from milk, it may possibly be exploited to increase the keeping quality of raw milk.

Animals↗