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Biomedical subjects

J Shepherd

Publications and source records attributed to J Shepherd.

At least 415 records · Page 23Linked to original sources
PubMed1965

Protein synthesis in rat liver: influence of amino acids in diet on microsomes and polysomes.

Rats were killed 1 hour after having been fed by stomach tube with amino acid mixtures that were either nutritionally complete or lacked tryptophan. Microsomes isolated from the livers of animals fed the incomplete mixture showed a reduced capacity to incorporate (14)C-leucine in vitro, and polysomes prepared from the same livers showed an increased proportion of monosomes and disomes. Prior treatment with actinomycin D did not prevent these differences in response to the two amino acid mixtures, an indication that synthesis of messenger RNA may not be involved in the cell mechanism which recognizes differences in amino acid pattern.

Amino Acids↗
PubMedDate not supplied

Prevention of heart disease: is LDL reduction the outcome of choice? No, there is more.

The West of Scotland Coronary Prevention Study (WOSCOPS), a placebo-controlled 5-year cohort study, demonstrated that the use of pravastatin decreased low density lipoprotein (LDL) levels and associated risk of myocardial infarction. The rate of occurrence of coronary events, however, was similar across the four lowest quintiles of LDL reduction (23-41% reductions in mean LDL levels). The relationship between reduction of LDL and the reduction of risk was not linear. Further analysis indicated that even in overlap groups where patients exhibited equivalent mean LDL levels on treatment, pravastatin treatment was associated with less risk of occurrence of coronary events than placebo treatment. These results suggest that while LDL level does serve as a predictor of the risk of coronary events, other factors exist that should be considered and investigated further.

Comment↗
PubMedDate not supplied

Invasive external otitis caused by Aspergillus.

Invasive external otitis occurs almost exclusively in patients with longstanding diabetes. Except for occasional cases, the etiologic agent has been Pseudomonas aeruginosa. We report a case caused by Aspergillus species in a diabetic patient with acute leukemia. Persistent infection was documented by culture and histology after a course of intravenous amphotericin B (total dose, 2 g). Clinical resolution occurred in association with a 3-month course of oral itraconazole. Four previously reported cases of invasive aspergillus otitis are reviewed.

Aspergillosis↗
PubMedDate not supplied

Prevention of coronary heart disease in clinical practice: a commentary on current treatment patterns in six European countries in relation to published recommendations.

Market research surveys can be a source of up-to-date information about current clinical practices. Data from one such survey, Cholesterol Monitor (made available by Merck & Co., Inc., Whitehouse Station, N.J., USA) was examined to ascertain to what extent management of cholesterol in six European countries conforms with the advice of the joint Task Force of the European Society of Cardiology, European Atherosclerosis Society and European Society of Hypertension for prevention of coronary heart disease (CHD). Rates of cholesterol testing in patients with CHD varied from less than 50% in the UK to more than 80% in France and Italy. Across Europe, the average cholesterol levels in surveyed patients was 6 mmol/l, and the average intervention level was 7.5 mmol/l. In all countries, there was evidence of a substantial treatment gap, even among high-risk patients with established CHD. This gap took the form of non-treatment of a proportion of patients whose risk status merited intervention on the basis of expert recommendations and the results of the Scandinavian Simvastatin Survival Study (in which sustained lowering of total and low-density lipoprotein cholesterol reduced total and coronary mortality in patients with baseline total cholesterol as low as 5.5 mmol/l). The findings indicate that a concerted programme of physician education is required if the recommendations of the joint Task Force are to be put into effect, and if the present nontreatment/undertreatment of cholesterol in high-risk patients is to be corrected.

Cholesterol↗
PubMedDate not supplied

Contribution of the receptor pathway to low density lipoprotein catabolism in humans. New methods for quantitation.

Receptor-mediated catabolism of low density lipoprotein (LDL) by cultured cells depends on the presence of functionally significant arginine and lysine residues on the lipoprotein apoprotein. When these are blocked, the recognition process is abolished, and catabolism of the modified lipoprotein is restricted to other mechanisms. Accurate discrimination between the activities of the receptor and nonreceptor pathways in vivo depends critically on the metabolic properties of this chemically modified lipoprotein. Here we report our experiences with two lysine-modified LDL tracers, glucosylated LDL (GLC-LDL) and 2-hydroxyacetaldehyde-treated LDL (HOET-LDL). The fractional clearance rate of GLC-LDL (0.25 +/- 0.05 pools/day, n = 5) was 50% of that of control material (0.51 +/- 0.09 pools/day) injected simultaneously into normal subjects. The HOET-LDL was also retarded in its clearance. Here, however, the fractional clearances of the control (0.37 +/- 0.06 pools/day, n = 6) and modified lipoprotein (0.19 +/- 0.03 pools/day) were lower than those obtained by the glucosylation procedure. We suspect that the prolonged incubation required for glucosylation of LDL artifactually accelerated its catabolism. The HOET-LDL does not suffer from this defect and seems to be a better tracer of the receptor-independent pathway. In a group of 10 subjects, HOET-LDL was metabolically indistinguishable from 1,2 cyclohexanedione-treated, arginine-modified LDL.

Acetaldehyde↗
PubMedDate not supplied

Fenofibrate reduces low density lipoprotein catabolism in hypertriglyceridemic subjects.

This study examines the kinetic basis for the increment in plasma low density lipoprotein (LDL) levels that accompanies the fenofibrate treatment of severely hypertriglyceridemic (HTG) patients. Seven HTG men with a mean plasma triglyceride level of 1470 mg/dl were treated for 6 weeks. During treatment, their plasma triglyceride level fell by 77% and their cholesterol level by 41%. The fall in very low density lipoprotein (VLDL) cholesterol level was reciprocated by increments in the cholesterol level in both LDL and high density lipoproteins (HDL); the rise in HDL was confined to HDL3. LDL catabolism was examined before and during therapy using native and chemically modified tracers in an attempt to distinguish receptor-mediated from non-receptor-mediated clearance. In their basal state, the hypertriglyceridemic subjects overcatabolized both the native and the modified lipoprotein, implying that the non-receptor pathways were hyperactive. The mean fractional clearance rate of LDL via the receptor pathway was not significantly different from normal. Fenofibrate therapy corrected the patients' hypercatabolism, reducing the receptor-independent fractional clearance of apo LDL by 50% (from 0.48 to 0.24 pools/day; p less than 0.05). The mean fractional catabolic activity of the receptor route did not change, but when the increment in the plasma apo LDL concentration was taken into account, it was clear that the drug treatment was associated with an increase in the net amount cleared by the receptor pathway and with a reduction of lipoprotein uptake into receptor-independent routes.

Adult↗
PubMedDate not supplied

Posterior chamber phakic intraocular lens for hyperopia.

PURPOSE: A Phase I U.S. FDA clinical study of a plate haptic posterior chamber phakic intraocular lens (STAAR Surgical Implantable Contact Lens) for treatment of hyperopia was conducted at 4 sites in the United States. The purpose of this report is to assess the short-term safety and efficacy. METHODS: Ten patients with hyperopia between +2.50 and +10.875 D were implanted in one eye each with the posterior chamber plate phakic intraocular lens and were examined at baseline and 1 day, 1 week, 1, 3, and 6 months after surgery. Mean baseline hyperopia was +6.63 D. RESULTS: At 6 months postoperatively, 7 of 10 eyes (70%) had an uncorrected visual acuity of 20/20 or better and 10 of 10 (100%) had 20/40 or better. Eight of ten eyes (80%) had a spectacle-corrected visual acuity within 1 line of baseline; the other two eyes (20%) had an improvement of 3 lines. Mean 6-month postoperative spherical equivalent refraction was +0.20 +/- 0.61D (range, -0.50 to +1.50 D), a reduction of 6.025 D from baseline. Eight of 10 eyes (80%) were within +/-0.50 D of emmetropia, 9 eyes (90%) were within +/-1.00 D, and all eyes (100%) were within +/-1.50 D. No operative or postoperative complications or adverse reactions were observed. CONCLUSIONS: Results support the short-term safety, efficacy, and predictability of the STAAR Surgical Implantable Contact Lens (plate haptic posterior chamber phakic intraocular lens) in the treatment of hyperopia.

Adult↗
PubMedDate not supplied

Educating children about heart disease.

The authors have designed a computer-based health education programme introducing coronary heart disease (CHD) prevention to primary school children using the novel authoring system, Course Builder. To aid design of the programme, the basic knowledge of a randomly selected group of 90 children aged 8-11 years old from three city schools was assessed, using a questionnaire in storyline format. This surveyed children's understanding of the heart's basic function, the importance and prevalence of CHD, and perception of CHD as a preventable disease. The children's response after using the programme and their increased knowledge and awareness were evaluated, and the programme was deemed an overwhelming success.

Child↗