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Biomedical subjects

J C Griffith

Publications and source records attributed to J C Griffith.

4 recordsLinked to original sources
PubMed2004

Variegate porphyria presenting with acute autonomic dysfunction, intussusception and renal infarction.

A 48-year-old man presented with abdominal pain, constipation and irritability one month after starting phenytoin treatment for a generalized seizure. He was hypertensive, tachycardic (BP 174/98, heart rate (HR) 100 bpm supine) and hypovolaemic. Abdominal CT demonstrated transient jejunal intussusception and infarction of the left kidney. Urinary porphobilinogen levels were increased and genetic analysis confirmed the diagnosis of variegate porphyria. Because of ongoing postural hypotension, the patient underwent further autonomic investigations. Levels of blood pressure (MBP), HR and muscle sympathetic activity (MSNA) were increased during the acute attack compared to recovery (131 versus 105 mmHg, 100 versus 60 bpm, 88 versus 26 bursts min(-1)). HR and MSNA did not increase during phase II Valsalva, whereas stroke volume (SV) decays were exaggerated (deltaMBP-56 versus 0-31 mmHg and SV 25% versus 40% baseline). Baroreflex failure causing increased sympathetic activity, decreased sympathetic and parasympathetic rapid responses, loss of splanchnic capacitance and renal salt wasting were the likely mechanisms for postural hypotension. Increased sympathetic activity may also have caused intussusception and focal renal vasoconstriction, both of which may be underdiagnosed causes of abdominal pain in acute porphyria.

Acute Disease↗
PubMed1998

Antidepressant-like effects of 5-hydroxytryptamine1A receptor agonists on operant responding under a response duration differentiation schedule.

A response duration differentiation schedule, where rats depress a lever for between 1.0 and 1.3 s to obtain a food reward, provides a useful measure for detecting antidepressant activity. It is known that 5-hydroxytryptamine1A (5-HT1A) receptor agonists exhibit antidepressant-like activity in multiple animal models of depression, however, compounds selective for this receptor have not been tested in this model to date. Thus, the present study sought to determine the effect of the full 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and the partial 5-HT1A agonist, buspirone, on responding in the response duration differentiation task. The effects of these drugs were compared to the effects of the non-specific serotonergic agonist, lysergic acid diethylamide (LSD); the phenothiazine, chlorpromazine; the atypical antidepressant, trazodone; and the non-selective 5-HT1A antagonists, propranolol and alprenolol. It was found that propranolol, trazodone, and both the full (8-OH-DPAT) and partial (buspirone) 5-HT1A agonists produced increases in the mean response duration, which is typical of antidepressant activity. By contrast, with the exception of propranolol, compounds lacking antidepressant efficacy (e.g. chlorpromazine, LSD and alprenolol), failed to produce increases in mean response durations. Further, the effects of 8-OH-DPAT were inhibited by pretreatment with the 5-HT1A antagonist, (-)-alprenolol (3.0 and 30.0 mg/kg i.p.). The results of this study provide further support for the suggestion that 5-HT1A agonists may be useful for the treatment of clinical depression and that these effects are specifically mediated by 5-HT1A receptors.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1991

Serendipitous finding of transitional cell carcinoma of the kidney on bone and gallium imaging.

A 50-year-old woman presented with low back pain. Bone scintigraphy showed a focus of increased activity in the upper pole of the left kidney. Subsequent Ga-67 citrate scintigraphy demonstrated this same abnormal focus as a region of increased activity. Ultrasonography showed a renal mass in the upper pole of the left kidney. At surgery a transitional cell carcinoma of the upper pole of the left kidney was found.

Bone and Bones↗