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Biomedical subjects

C Fox

Publications and source records attributed to C Fox.

At least 109 records · Page 6Linked to original sources

Pharmacokinetics of oral ciprofloxacin, 100 mg single dose, in volunteers and elderly patients.

The pharmacokinetics of ciprofloxacin following a single 100 mg oral dose were evaluated in elderly patients (mean age 74 years), laboratory staff (30-40 years) and students (less than 20 years). There were no significant differences in serum Tmax (1.2-1.3 h) or in overall serum elimination half-life (3.7-4.0 h) but Cmax in elderly patients was more than double that in young volunteers (P less than 0.005). The serum AUC value was greater both in fasting students (1.4 mg/h/l) compared with the same subjects after food (1.09: P less than 0.01) and, after food, in elderly patients (1.95) compared with students (0.81: P less than 0.005). Urinary recoveries were greater in fasting subjects and in all categories of volunteers compared with elderly patients. However, in the elderly, urinary ciprofloxacin concentrations (0-6 h mean 66 mg/l: range 17.4-200 mg/l) were more than adequate for the eradication of urinary pathogens.

Administration, Oral↗

Chylous cyst of the transverse colon.

A patient, who proved to have a chylous cyst of the colon, presented with bright red rectal bleeding and an abnormality on barium enema suggesting a colonic polyp. We review such an unusual presentation and other reported cases.

Aged↗

Oral cefuroxime axetil: clinical pharmacology and comparative dose studies in urinary tract infection.

Cefuroxime axetil, an orally absorbed pro-drug of cefuroxime was used to treat a mainly elderly group of patients with symptomatic urinary tract infections. The drug was clinically effective and the bacteriological short term and long term cure rates (55% and 48% respectively) comparable to those of other antibiotics. The study had to be terminated however after the development of three cases of antibiotic associated colitis. Studies of the pharmacokinetics of the drug in volunteers gave inconsistent results suggesting that there may be variable bioavailability of the compound.

Administration, Oral↗

Sultamicillin (CP-49, 952): evaluation of two dosage schedules in urinary infection.

The results of a clinical trial of sultamicillin, a novel mutual pro-drug combination of ampicillin and the beta-lactamase inhibitor sulbactam, in ampicillin-resistant urinary tract infections are reported. The majority of infections treated occurred in elderly geriatric in-patients. Two dosage schedules were investigated, both resulting in the same total daily dosage (1500 mg sultamicillin). These were 750 mg sultamicillin, 12-hourly (series I) and 500 mg sultamicillin, 8-hourly (series II), each administered orally for seven days. Short term cure rates (after exclusion of superinfections and reinfections) of 79.5% (series I) and 82% (series II) were obtained one week after therapy, falling to 69% and 50%, respectively, at three to six week follow up. Sultamicillin was well tolerated. Pharmacokinetic studies confirmed intestinal absorption of both constituents in young volunteers and in the elderly.

Aged↗

Parallel measurements of bound calcium and force in glycerinated rabbit psoas muscle fibers.

A simple double-isotope procedure has been developed for making simultaneous measurements of bound Ca2+ and relative force in glycerinated rabbit psoas bundles containing two fibers. With this preparation it is possible to study Ca2+-troponin interactions coincident with MgATP-induced force development. Over the free [Ca2+] range 6 . 10(-8)--1.2 . 10(-5) M the bound Ca2+ varied from 0.25 to 1.65 mumol/g protein. The free [Ca2+] at half-maximal Ca2+ saturation was 2 . 10(-7) M while that a half-maximal force was 5 . 10(-7) M. Half-maximal Ca2+ saturation was associated with 20% maximal force. The force-[Ca2+] saturation curve showed a steep rise in slope at greater than half saturation. The observed relationship was consistent with a model in which multiple occupancy of troponin Ca2+-binding sites is essential for initiation of cross-bridge cycling.

Animals↗

Pupillary signs in diabetic autonomic neuropathy.

Pupillary function was investigated in 36 insulin-dependent diabetics and 36 controls matched for age and sex. About half of the diabetics had evidence of peripheral somatic or autonomic neuropathy, or both. The diabetic patients had abnormally small pupil diameters in the dark and less fluctuation in pupil size (hippus) during continuous illumination than the controls. They also had reduced reflex responses to light flashes of an intensity adjusted for individual retinal sensitivities. The pupillary findings were compared with results of five tests of cardiovascular function and five tests of peripheral sensory and motor nerve function. Almost all the patients with autonomic neuropathy had pupillary signs, which we therefore conclude are a common manifestation of diabetic autonomic neuropathy.

Adolescent↗

Lecithin--cholesterol acyltransferase and the lipoprotein abnormalities of obstructive jaundice.

1. We have studied the plasma lipoprotein abnormalities in obstructive jaundice to test the hypothesis that the abnormalities would correlate with plasma lecithin--cholesterol acyltransferase activity. 2. Very-low-density lipoproteins (VLDL) were normal in composition and had a normal pre-beta electrophoretic mobility when lecithin--cholesterol acyltransferase activity was high. When it was low VLDL had abnormal composition and ran in the beta position. 3. With high lecithin--cholesterol acyltransferase activity, low-density lipoprotein (LDL) was normal and cholestatic LDL (LP-X) was not found. With low lecithin--cholesterol acyltransferase activity up to three LDL fractions were found: (i) large triglyceride-rich particles, (ii) LP-X and (iii) a triglyceride-rich cholesteryl ester-poor particle of normal dimensions. 4. High-density lipoprotein (HDL) concentrations correlated with lecithin--cholesterol acyltransferase activity and HDL were normal in composition and electron-microscopic appearance when the activity was high. When lecithin--cholesterol acyltransferase activity was low HDL was abnormal in composition and 'stacked discs' were seen on electron microscopy as well as normal spherical particles. 5. These results suggest that low lecithin-cholesterol acyltransferase activity may cause at least some of the lipoprotein changes of obstructive jaundice.

Adult↗

Streptozotocin-induced renal tumours in rats.

Forty-six separate renal tumours developed in 36/80 Wistar male rats given a single i.v. dose of streptozotocin (25 mg/kg body wt) to induce diabetes mellitus. Fourteen of the tumours were epithelial in type, 8 were wholly mesenchymal and 24 were largely mesenchymal but also contained epithelial elements. The purely epithelial tumours correspond to the renal adenomas and adenocarcinomas seen in man. The mesenchymal tumours were composed either of undifferentiated spindle cells or of a mixutre of poorly differentiated mesenchyme and epithelial glands. Microscopically, the mixed tumours resembled the nephroblastomas seen in man; both elements appeared to be malignant, but in the absence of metastases this remains unproven. The management of the diabetic state did not influence the incidence of tumours, but insulin appeared to enhance tumour growth.

Animals↗