Biomedical subjects

P Hession

Publications and source records attributed to P Hession.

4 recordsLinked to original sources

PubMed2001

Long-range reactive dynamics in myoglobin.

We report the complete vibrational spectrum of the probe nucleus 57Fe at the oxygen-binding site of the protein myoglobin. The Fe-pyrrole nitrogen stretching modes of the heme group, identified here, probe asymmetric interactions with the protein environment. Collective oscillations of the polypeptide, rather than localized heme vibrations, dominate the low frequency region. We conclude that the heme "doming" mode is significantly delocalized, so that distant sites respond to oxygen binding on vibrational time scales. This has ramifications for understanding long-range interactions in biomolecules, such as those that mediate cooperativity in allosteric proteins.

Animals↗

PubMed1999

Intravenous urography in urinary tract surveillance in carcinoma of the bladder.

AIMS: The need for intravenous urography (IVU) in upper tract surveillance for primary transitional cell carcinoma (TCC) of the bladder is contentious. We reviewed our intensive screening policy in the follow-up of these patients to ascertain if such a policy is required and if specific groups could be identified to rationalise this protocol. METHODS: Review of the clinical and radiological data on 174 patients with a diagnosis of primary TCC of the bladder attending a teaching hospital urology department. RESULTS: Eight upper tract 'lesions' were identified: six TCC and two false-positive examinations using IVU. No link was demonstrable between upper tract recurrence and tumour stage, grade or multiplicity at diagnosis. All had recurrent bladder tumour but four of the six upper tract tumours occurred at 72 months or later. Twenty-nine patients over the study period developed either a dilated pelvi-calyceal system or a non-functioning kidney detected on IVU. CONCLUSIONS: Upper tract TCC can present late and patients with early bladder recurrence and those who do not show a reduction in bladder tumour number at follow-up cystoscopy are most at risk. IVU can probably be safely abandoned in those without local recurrence at 24 months. IVU is sensitive but not specific for upper tract tumour but also yields other relevant clinical information concerning the renal tract. Screening for upper tract metachronous disease should therefore be confined to those with recurrent transitional cell carcinoma of the bladder.

Adult↗

PubMed1997

Imaging appearances of ileouterine fistula complicating recurrent adenocarcinoma of the rectum.

Enterouterine fistulae are rare and nowadays are most commonly due to pelvic tumours. We review the literature and present the case of a woman who presented with an ileouterine fistula following surgery and radiotherapy for recurrent rectal adenocarcinoma. The presence of tumour within the fistula track may also have been a significant aetiological factor. Magnetic resonance imaging (MRI) is an excellent method to demonstrate the site and size of the track and has not, to date, been used to identify such a fistula.

Adenocarcinoma↗

PubMed1988

Effects of catecholamines on serum lipoproteins of normally fed and cholesterol-fed rabbits.

The effects of catecholamines on the regulation of lipoprotein metabolism have not been defined. We examined the effects of subcutaneously administered slow-release preparations of norepinephrine (2 mg/kg) and isoproterenol (0.2 mg/kg) on the serum lipoproteins of New Zealand White rabbits. Drugs or control suspension were administered daily to three groups of normally fed and three groups of cholesterol-fed rabbits, and lipoprotein analysis was performed at intervals over a 60-hour period. In the normally fed animals, norepinephrine increased the serum levels of triglyceride and phospholipid by factors of 2.4 (P less than .01) and 1.35 (P less than .05), respectively, compared with control animals at 60 hours, but had no effect on serum cholesterol. All components of serum very low density lipoproteins (VLDL: triglyceride, cholesterol, phospholipid, and protein) were significantly (P less than .01) elevated by norepinephrine in the normally fed animals. In the cholesterol-fed animals, norepinephrine at 60 hours significantly increased total serum cholesterol, triglyceride, and phospholipid concentrations by factors of 1.7 (P less than .05), 5.0 (P less than .01), and 1.6 (P less than .05), respectively, compared with controls. The norepinephrine effects in these animals was due to significant elevation of total VLDL and low density lipoproteins (LDL) and all their elemental components. Isoproterenol produced no significant effect on serum lipoprotein levels in the normally fed rabbit, but in cholesterol-fed animals it produced a rise in total serum VLDL and LDL triglyceride concentrations compared with controls at 60 hours. These data demonstrate that catecholamines are involved in the regulation of lipoprotein metabolism.

Animals↗