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Biomedical subjects

C Allen

Publications and source records attributed to C Allen.

At least 199 records · Page 11Linked to original sources
PubMed1983

Intrastromal noninflammatory bacterial colonization of a corneal graft.

Progressive branching, needlelike stromal opacities were observed within a corneal transplant. Analysis of the corneal button by light microscopy and transmission electron microscopy disclosed a localized epithelial ingrowth into the stroma at a suture tract accompanied by intrastromal pockets of gram-positive cocci extending across the cornea. No inflammatory reaction was found in the areas of bacterial colonization. To our knowledge, noninflammatory bacterial colonization of the stroma of a corneal transplant has not been previously described.

Aged↗
PubMed1983

Alimentary lipemia: plasma high-density lipoproteins and apolipoproteins CII and CIII in healthy subjects.

Three healthy male and three female inpatient volunteers consumed isocaloric diets for 4 wk. At weekly intervals, a fatty meal (100 g fat) was consumed by each fasting subject and blood drawn at 2 h intervals for 12 h. Of the four oral fat loads, two contained saturated fat (polyunsaturated/saturated fat ratio = 0.34) and two contained unsaturated fat (polyunsaturated/saturated fat = 2.21). The magnitude of alimentary lipemia, expressed as area under the plasma triglyceride curve, was 3- to 4-fold higher in males than females. Alimentary lipemia was inversely related to the subjects' fasting plasma high-density lipoprotein (HDL)-cholesterol, HDL apolipoprotein (apo) CIII and directly related to plasma triglycerides. The P/S ratios of the daily diet or the fat meal did not significantly influence the plasma triglyceride curve. After fat intake, mean (+/- SEM) plasma total apoCII and CIII fell to 54 +/- 20% and 73 +/- 5% of base-line, respectively, at 12 h in five of six subjects. After oral fat, an initial fall and a subsequent rise in apoCII and CIII in HDL was associated with reciprocal changes in apoC concentrations in very low-density lipoproteins. We speculate from the data that 1) plasma HDL and their apoC concentrations are important determinants of chylomicron clearance and 2) transfer of apoCs from HDL to triglyceride-rich lipoproteins in the early phase of fat absorption does not result in the total recycling of apoCs from these lipoproteins to HDL during the late phase of alimentary lipemia.

Adolescent↗
PubMed1983

Sucrose polyester: substitution for dietary fats in hypocaloric diets in the treatment of familial hypercholesterolemia.

In five obese women heterozygous for familial hypercholesterolemia, we assessed the combination of weight loss and sucrose polyester (SPE) in lowering low-density lipoprotein cholesterol (LDLC). After a 10-day basal hypocaloric (1426 cal/day), 270 mg cholesterol, P/S 1.2:1 diet, an average of 36 g of dietary fat/day was replaced by 36 g of an 80/20 SPE-hydrogenated palm oil mixture, providing 30 g SPE for 30 days; during the SPE substitution period mean dietary cholesterol and P/S were unchanged, mean caloric intake was 1104 cal/day. During the hypocaloric basal diet, mean weight fell 1.2 kg, p less than 0.02, total plasma cholesterol fell 8% from 358 +/- 46 to 330 +/- 47 mg/dl, p less than 0.01, LDLC fell 4% from 264 +/- 37 to 254 +/- 44 mg/dl, p greater than 0.1, and mean high-density lipoprotein cholesterol fell 11%, from 52 +/- 4 to 46 +/- 4, p less than 0.05. Over the 30-day SPE substitution, mean cholesterol fell 20% from 330 +/- 47 at the end of the basal diet to 265 +/- 42 mg/dl, p less than 0.001; mean LDLC fell 23%, from 254 +/- 44 to 195 +/- 41 mg/dl (p less than 0.01); weight fell 4%, p less than 0.01, from 91 +/- 7 to 87 +/- 7 kg, and mean high-density lipoprotein cholesterol fell 11% from 46 +/- 4 to 41 +/- 2, p less than 0.05. Hypocaloric removal of dietary fat by SPE, an artificial fat with culinary properties of conventional dietary fats, effectively reduces LDLC (by 23%) in familial hypercholesterolemia subjects, with additive effects of SPE and weight loss.

Body Weight↗
PubMed1983

Membrane Fc-IgG and C3b receptors on myeloid leukaemia cells: a comparison with cytoplasmic acid naphthyl acetate esterase cytochemistry.

Membrane receptors for IgG and C3b were examined on blast cells from 57 cases of acute myeloid leukaemia. These acute leukaemias were classified as myeloblastic, myelomonocytic or monocytic following morphological, cytochemical, and immunological investigations. The membrane receptors of leukaemic blast cells appear to be directly related to the degree of monocytic differentiation with the lowest receptor activities found in acute myeloblastic leukaemia. A comparison was also made between receptor and cytoplasmic acid naphthyl acetate esterase (ANAE) activities in 29 morphologically and immunologically-defined myelomonocytic and monocytic leukaemias. This study revealed that the receptor-positive "monocytic component" in a significant proportion of cases showed unexpectedly weak or negative ANAE reactions suggesting a more cautious approach to the interpretation of ANAE cytochemistry in acute leukaemias. The normal development of cytoplasmic ANAE and membrane receptors is also discussed and compared with their abnormal patterns of expression associated with leukaemic transformation.

Carboxylic Ester Hydrolases↗
PubMed1982

Sucrose polyester and covert caloric dilution.

Total daily caloric intake was measured in 10 obese subjects when sucrose polyester (SPE), a nonabsorbable synthetic fat, covertly replaced conventional fats in a single crossover study consisting of three periods: a period of 7 to 14 days to determine baseline caloric intake and two 20-day study periods. An average of 60 g SPE/day replaced conventional fat in one of the two study periods. During both study periods, 60% of the base line caloric intake was "required intake" at mealtime; an additional 60% of base line caloric intake was allowed as "free choice" foods at a specified snacktime. It was thus possible during both study periods to consume more than 100% of the base line caloric intake. In the SPE study period, 40 g SPE replaced 40 g conventional fat for every 1200 kcal of required intake, resulting in a 30% reduction in mealtime caloric intake. Mean total caloric intake (meal and snack) fell 23% during the SPE period (p less than 0.05), despite an average daily weight loss of 0.18 kg. Snack caloric intake did not increase significantly to compensate for caloric dilution of the meals during the SPE period. These results indicate that the obese may not detect or may not compensate for covert dilution of fat calories with SPE. In addition, during the SPE period, there was a 10% reduction in total plasma cholesterol, a 14% reduction in low-density lipoprotein cholesterol, and a 10% reduction in triglyceride concentration. Thus, fat replacement with SPE may benefit weight reduction regimens in obese subjects by facilitating decreased caloric intake and by improving the circulating lipoprotein profile as well.

Adult↗
PubMed1982

Effects of dietary carbohydrate and fat on plasma lipoproteins and apolipoproteins C-II and C-III in healthy men.

Effects of isocaloric changes in dietary fat and carbohydrate on plasma apolipoproteins (apo) C-II, C-III, and lipoproteins were assessed in nine healthy men. Carbohydrate and fat comprised 80% of total calories. After a 1-week basal diet (40% of calories from carbohydrate), the subjects received either a high (65% of calories) or low (15% of calories) carbohydrate diet for 3 weeks; subsequently the diets were switched, those initially on high carbohydrate going on to low carbohydrate, and vice versa, and the new diets were maintained for 3 weeks. ApoC-II, C-III, and triglycerides initially rose and then declined during the high carbohydrate diet period; high density lipoprotein cholesterol (HDL-C) decreased. Comparing results after 3 weeks of high carbohydrate diet to those after 3 weeks on low carbohydrate, we observed the following significant differences: 1) total plasma apoC-II and C-III were higher; the apoC-III/C-II ratio in very low density lipoproteins (VLDL) and in the lighter HDL subfraction (HDL2) was lower indicating net lipoprotein enrichment with apoC-II than with apoC-III; 2) unsialylated apoC-III0 comprised a higher percent of total VLDL apoC-III mass; 3) HDL2 and HDL2/HDL3 ratio were lower. Isocaloric changes in dietary carbohydrate and fat cause significant alterations in plasma levels of VLDL and HDL 2, the two major lipoproteins that transport apoC-III and apoC-II. Diet-induced changes in circulating apoC-III and C-II may, in part, play a role in regulation of plasma triglycerides in man.

Adult↗
PubMed1981

Experimental studies on cerebellar foliation. I. A qualitative morphological analysis of cerebellar fissuration defects after neonatal treatment with 6-OHDA in the rat.

The present report describes the natural history of defective cerebellar fissuration in the rat after neonatal treatment with 6-hydroxydopamine (6-OHDA). Within 24 hours after an intracisternal (IC) injection of 100 micrograms 6-OHDA cerebellar pial fibroblasts degenerated almost completely and were phagocytosed b macrophages within 2-5 days postinjection (dpi) leaving the cerebellar surface denuded of pia. Bergmann glia end feet at first exhibited morphological signs of gliosis and later formed new sprouts that penetrated the basal lamina and grew into the subarachnoid space covering regenerating pial fibroblasts and also invading ectopic colonies of external granular layer (EGL) cells. Breaches in the basal lamina appeared after the pial fibroblast had been destroyed and were confined to areas where Bergmann glia end feet were absent and where EGL cells were opposed to the basal lamina. EGL cells escaped through these fractures into the subarachnoid space in the fissures, where they proliferated to form large colonies of granule and stellate cells. In those fissures in which EGL ectopia featured, opposing folia fused and fissures were lost. These findings suggest that pial fibroblasts and the basal lamina have an important role in maintaining lobular partition during development of the cerebellum, in establishing cerebellar fissures, and in consolidating Bergmann glia-EGL cell relationships as a prerequisite for orderly migration of EGL cells.

Animals↗
PubMed1981

IgG antiglobulins in rheumatoid arthritis and other arthritides: relationship with clinical features and other parameters.

A radioimmunoassay has been developed for measuring IgG antiglobulins using baboon IgG as antigen. Raised levels were virtually confined to the sera of patients with rheumatoid arthritis (RA) and not found in other seronegative arthritides. High levels were found in both seropositive and seronegative (as judged by latex slide and sheep cell differential agglutination for IgM antiglobulins) patients with RA and were associated with systemic disease but not synovitis. Very high levels (more than twice the upper limit of normal) showed a strong association with vasculitis.

Antibodies, Anti-Idiotypic↗
PubMed1981

IgG rheumatoid factor, complement and immune complexes in rheumatoid synovitis and vasculitis: comparative and serial studies during cytotoxic therapy.

IgG and IgM rheumatoid factors (IgG-RF and IgM-RF), complement and three assays for immune complexes were measured in 22 patients with rheumatoid arthritis (RA) complicated by either chronic active synovitis or vasculitis. Patients with vasculitis had relatively inactive arthritis but had higher titres of rheumatoid factors, especially IgG-RF, anticomplementary activity (ACA) and lower levels of C4 than those with synovitis. Clq-binding and platelet aggregation (PA) levels were similar in both groups. Serial measurements during cytotoxic therapy showed a close temporal relationship between the clinical features of vasculitis and levels of IgG-RF, ACA and C4 both with remission and with relapse. We suggest that immune complexes containing IgG-RF which activate complement and are detected by ACA are useful markers of rheumatoid vasculitis and may be important in its pathogenesis.

Antigen-Antibody Complex↗
PubMed1980

The isolation of immune complexes containing IgM rheumatoid factor and recovery of IgG rheumatoid factor from the complexes.

IgG with rheumatoid factor activity has been recovered from immune complexes containing IgM rheumatoid factor. This was done by passing serum from patients with rheumatoid arthritis through an immunoadsorbent column of the F(ab')2 fragment of rabbit anti-human mu chain. The recovered IgM was analysed by radioimmunoassays for IgM and IgG rheumatoid factors before and after sucrose density gradient centrifugation at neutral and acid pH. It is considered that the method may be generally applicable for the isolation of immune complexes containing IgM antibodies.

Animals↗
PubMed1980

Effect of sucrose polyester on fecal bile acid excretion and composition in normal men.

The effects of sucrose polyester (SPE) (a nonabsorbable mixture of hex-a, hepta,- and octa-fatty acid esters of sucrose with physical properties similar to those of common dietary fats) on fecal bile acid excretion and composition were assessed in 24 healthy, nonobese, normolipemic male volunteers, in a 40-day, inpatient, metabolic balance study. Isocaloric diets provided either 800, 300, or less than 50 mg of cholesterol/day (P/S ratios respectively 0.4, 1.0, and 1.5). After diet-only perids of 10 days (for the 800 and 300 mg cholesterol regimens), and 21 days (for the 50 mg diet), the diets were continued for 30 days, with addition of SPE to diets over three successive treatment periods of 10 days each, with 8, 16, and 35 g of liquid SPE/day, or 15, 30, and 50 g SPE/day in a SPE-hydrogenated palm oil mix. On both the liquid SPE and SPE-hydrogenated palm oil mix, there were no significant changes in fecal bile acid excretion as a function of dietary SPE, at any level of cholesterol intake, P > 0.1. In most subjects SPE changed fecal bile acid composition; lithocholic acid was decreased, and in most instances this was accompanied by the appearance and increase in chenodeoxycholic acid. In one subject, both deoxycholic and 3 beta, 12 alpha-dihydroxycholanic acid were reduced, with an accompanying increase in cholic acid. The hypocholesterolemic effect of SPE appears to be mediated through its reduction of intestinal absorption of cholesterol, not through effects on bile acid excretion.

Adult↗
PubMed1980

Effects of alcohol ingestion on lipids and lipoproteins in normal men: isocaloric metabolic studies.

To investigate metabolic relationships between alcohol ingestion and fasting plasma high density lipoprotein cholesterol (C-HDL) and triglycerides, seven young normal males were assessed with isocaloric substitution of alcohol for carbohydrate in the diet. For a 5-week study period, an isocaloric low cholesterol diet containing 20% of the calories as protein, 40% as fat, and 40% as carbohydrate, with < 300 mg cholesterol per day, P/S 1.5/1, was ingested. In weeks 2 and 3, 35 and 53 g/day of 100 proof Vodka were ingested, with isocaloric substitution of alcohol for dietary carbohydrate during these study weeks. In week 5, 1.35 g/day of lecithin linoleate was added to assess another putative nutritional approach to increasing C-HDL levels. By two-way analysis of variance and Scheffe's paired t tests, there were no significant differences in either C-HDL or triglyceride levels for any of the five metabolic diet, alcohol substitution diet periods; additionally, there were no significant effects of lecithin on plasma lipids or lipoproteins. The general question asked, "Does alcohol affect C-HDL levels?" is answered negatively for isocaloric alcohol substitution, on a cholesterol-poor, high P/S, and relatively carbohydrate restricted diet, for a 2-week period of moderate alcohol intake. Alcohol's effect on C-HDL and triglyceride probably involves an interaction with total calories, and perhaps with dietary composition (cholesterol, saturated fat, carbohydrate content), as well as the amount of ethanol ingested, and duration of intake.

Adolescent↗
PubMed1980

Psychosocial and psychosomatic diagnoses in primary care of children.

In this study in seven primary care facilities the proportion of children recognized as having behavioral, educational, or social problems was much higher than generally assumed. Although there was great variability among the facilities, at least 5% and as many as 15% of children seen in one year were diagnosed as having these problems in all but the hospital teaching facilities. The prevalence was even higher among children from poor families. The variability among facilities was much less for psychosomatic problems, which were diagnosed in 8% to 10% of the children. For both psychosocial and psychosomatic types of problems, but especially for psychosocial ones, the proportion of visits with the diagnoses was much lower than the proportion of children with them, so that these problems engendered fewer visits for their management than might have been expected from their frequency in the population. However, available evidence suggests that individuals with unresolved psychosocial problems make more than their share of visits for other diagnoses. The findings of this study have implications for the content of educational programs for primary care practitioners, for the organization of primary care practice, and for the current debate over policy concerning reimbursement and benefit packages.

Adolescent↗