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Biomedical subjects

A Richardson

Publications and source records attributed to A Richardson.

At least 253 records · Page 14Linked to original sources
PubMed1990

Characteristics of lipid substances activating the ileal brake in the rat.

Studies were carried out in 36 adult male rats to determine the characteristics of lipid substances which, after infusion into the ileum, slow the stomach to caecum transit time of the head of a bean meal in the rat. Stomach to caecum transit time was measured by environmental hydrogen analysis. Ileal infusion of a range of free fatty acids including petroselinic, oleic, myristoleic, erucic, linoleic, and linolenic all significantly slowed stomach to caecum transit time, as did the detergents (sodium bis (2-ethyl hexyl) sulphosuccinate and sodium linoleyl sulphate), the triglyceride corn oil, and the phospholipid lecithin. Although the lipid soluble deconjugated bile acid deoxycholic acid slowed stomach to caecum transit time, the water soluble conjugated bile acid taurocholic acid accelerated it. Infusion of the lipid alcohol oleyl alcohol and the calcium chelating agent disodium edetate (EDTA) into the ileum did not delay the passage of the meal through the stomach and small intestine. The diversity of lipid substances activating the ileal brake suggest a nonspecific effect by lipid soluble substances that can penetrate cell membranes. The lack of effect of EDTA suggested that calcium binding was not important.

Analysis of Variance↗
PubMed1990

Porcelain and resin veneers clinically evaluated: 2-year results.

A clinical comparison of two different types of dental veneers--baked porcelain veneer and heat-and-pressure processed urethane resin veneer--was made after 2 years. Although the esthetic appearance and gingival response were equal for both systems, the resin veneers had a greater tendency to chip and fracture. By the end of 2 years, 20% of the resin veneers had failed, whereas all of the porcelain veneers remained.

Acrylic Resins↗
PubMed1990

Eruptive changes in the axial inclination of lower incisor teeth--a longitudinal study.

A longitudinal cephalometric study investigated the change in lower incisor inclination in a group of 32 subjects over a period from 5-10 years of age, with yearly cephalometric radiographs and 6 monthly study models. In a previous study, it was shown that in all of these subjects, the lower incisors became more proclined over this 5 year period. Changes in the rate of proclination of the lower incisors over this period were studied, and this was related to events such as eruption, and contact with the upper incisors or palatal mucosa where this occurred. The association between the inclination of lower incisors before and just after eruption, and their "final" inclination was investigated, and the possible explanations and implications of the findings are discussed.

Child↗
PubMed1990

Survey of general practitioners' opinions on the role of radiology in patients with low back pain.

Ninety general practitioners responded to a questionnaire about the role of radiology in patients with low back pain. Their clinical indications for requesting radiographs were mostly in agreement with the opinions of radiologists, but nearly 80% requested investigations for their own or patients' reassurance. Understanding of the terms used by radiologists was good, although 25% thought that acute disc prolapse could be demonstrated on plain films. Previous training in radiology did not seem to influence knowledge. When general practitioners understood radiological terms they had clear therapeutic and specialist referral preferences. Poorly understood terms and those with which they were familiar but unclear about the implications for management were also identified.

Attitude of Health Personnel↗
PubMed1989

Changes in the expression of superoxide dismutase and catalase as a function of age and dietary restriction.

The activities of superoxide dismutase (Cu/Zn) and catalase were observed to decrease significantly between 6 and 29 months of age in rat liver. The decrease in superoxide dismutase and catalase activity was paralleled by a decrease in the levels of the mRNA species coding for these enzymes and the nuclear transcription of the superoxide dismutase and catalase genes. Life-long dietary restriction was shown to increase the expression (i.e. activities, mRNA levels, and nuclear transcription) of superoxide dismutase and catalase in liver tissue from 18-month-old rats.

Aging↗
PubMed1989

Dangerous dogs.

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Animals↗
PubMed1989

Analysis of effect of age on synthesis of specific proteins by hepatocytes.

The effect of age on the synthesis of specific proteins by hepatocytes was studied in Fischer F344 rats using two-dimensional polyacrylamide gel electrophoresis. Almost all proteins synthesized by hepatocytes from young rats were synthesized by hepatocytes isolated from old rats. Of over 500 proteins visually compared by two-dimensional polyacrylamide gel electrophoresis, only 11 proteins were observed to disappear and/or appear consistently with increasing age. The rates of synthesis of 36 randomly chosen proteins were quantified. Interestingly, the synthesis of 35 of the 36 proteins decreased between 5 and 30 months of age. The decrease in protein synthesis varied (15% to 70%) from one protein to another; i.e., a heterogeneity was observed in the age-related decrease in the synthesis of proteins. The age-related decrease in protein synthesis was statistically significant for 53% of the proteins studied. The total decrease in the rate of synthesis of all 36 proteins studied was 40% between 5 and 30 months of age, which is essentially the same as the decrease in total protein synthesis by suspension of hepatocytes isolated from 5- and 30-month-old rats. The results of this study demonstrate that the mechanism underlaying aging is different from development, which is characterized by a major change in the species of proteins synthesized by a cell.

Aging↗
PubMed1989

The effect of aging and dietary restriction on DNA repair.

DNA repair was studied as a function of age in cells isolated from both the liver and the kidney of male Fischer F344 rats. DNA repair was measured by quantifying unscheduled DNA synthesis induced by UV irradiation. Unscheduled DNA synthesis decreased approximately 50% between the ages of 5 and 30 months in both hepatocytes and kidney cells. The age-related decline in unscheduled DNA synthesis in cells isolated from the liver and kidney was compared in rats fed ad libitum and rats fed a calorie-restricted diet; calorie restriction has been shown to increase the survival of rodents. The level of unscheduled DNA synthesis was significantly higher in hepatocytes and kidney cells isolated from the rats fed the restricted diet. Thus, calorie restriction appears to retard the age-related decline in DNA repair.

Aging↗
PubMed1989

Age-related changes in protein phosphorylation by rat hepatocytes.

The qualitative and quantitative changes in the phosphorylation of specific proteins in hepatocyte suspension from 5-, 12- and 22-month-old male Fischer F344 rats were analyzed by two-dimensional polyacrylamide gel electrophoresis. No qualitative changes in phosphorylation of individual proteins were observed with age. In addition, very few quantitative changes (less than 2% of proteins studied) in protein phosphorylation were detected. The phosphorylation of two acidic proteins decreased (50%) with age while the phosphorylation of one basic protein increased (300%) with age. The two acidic proteins and one basic protein that showed quantitative changes with age were found predominately in the microsome and nuclear fractions of hepatocytes, respectively. The effect of dietary restriction on the phosphorylation of proteins in male Fischer F344 rats was also studied. Although, dietary restriction alters the age-related incident of disease and prolongs longevity, it did not have any significant effect on phosphorylation of individual proteins in the liver.

Aging↗
PubMed1989

A profile of long-stay psychogeriatric patients.

An assessment of 106 long-stay psychogeriatric in-patients in an East London borough was made using the CAPE and supplementary items in order to obtain a comprehensive picture of their needs; 51 long-stay residents in the care of local authority social services provided a comparison. Patients in hospital were found to be more disturbed, more disabled and more dependent than residents in local authority care.

Activities of Daily Living↗
PubMed1989

Expression of calbindin-D decreases with age in intestine and kidney.

The calbindins are Ca-binding proteins whose expression is regulated by 1,25-dihydroxyvitamin D3, the active metabolite of vitamin D3. The calbindins are found in high amounts in the proximal intestine (calbindin-D-9k) and the kidney (calbindin-D-28k), and they are thought to play a role in Ca transport by these tissues. Ca absorption by the intestine and perhaps the kidney declines with age, and this could be due to decreased expression of calbindin. Therefore, the expression of calbindins-D-9k and -D-28k was measured in F344 rats aged 2, 6, 13, and 24 months. mRNA levels were measured by dot blot hybridization to synthetic cDNA oligonucleotide probes, and protein levels were measured by enzyme-linked immunosorbent assay using specific antisera. Intestinal calbindin-D-9k mRNA decreased markedly between 2 and 6 months of age, but it then increased significantly between 13 and 24 months. Calbindin-D-9k protein paralleled the decrease in mRNA between 2 and 6 months, but continued to decline at 13 and 24 months despite the rise in mRNA. In the kidney, calbindin-D-28k mRNA declined between 2 and 13 months and then plateaued. Calbindin-D-28k protein followed a similar pattern. In the same studies expression of calmodulin by the intestine and kidney did not change with age. Plasma 1,25-dihydroxyvitamin-D3 correlated well with the expression of calbindin-D-9k in the intestine at 2 and 6 months of age and with the expression of calbindin-D-28k in the kidney at all ages. Decreased expression of calbindin-D with age may contribute to the age-related decrease in Ca transport in intestine and kidney.

Aging↗
PubMed1989

Surgical and orthodontic management of compound odontoma.

Practitioners should always consider the possibility of an odontoma when the eruption of teeth is delayed. The authors report an example of compound odontoma associated with delayed eruption of incisor teeth, and describe the surgical and orthodontic management of the case.

Child↗
PubMed1989

Matters relating to tooth sizes in Kenyan and British subjects.

The mesio-distal widths of teeth and the breadth of the dental arches were measured on study casts of twenty young Kenyan African males and twenty young male British adults in Belfast, Northern Ireland. All subjects had normal occlusion. Measurements were repeated for reproducibility testing which proved satisfactory. With the exception of the lower central incisor, all the Kenyan teeth were larger than their Caucasian counterparts, but only the differences relating to the premolar and molar teeth reached the level of statistical significance. The lower arch breadths measured between the first premolars and between the first permanent molars proved significantly greater in the Kenyan group. In the upper arch, the mean premolar breadth was greater but the difference in molar breadth was not statistically significant. This finding relates to the diminished buccal overjet in the Kenyan subject.

Black People↗
PubMed1989

Primary sepsis presenting as fulminant hepatic failure.

Four patients who were referred to the Liver Failure Unit with an initial diagnosis of fulminant hepatic failure were found to have severe bacterial infection from a primary septic focus as the cause of their illness. Clinical and biochemical characteristics were not helpful in differentiating these patients from those with hepatic failure from other causes, and only a high degree of suspicion will prevent delay in the diagnosis of underlying sepsis and initiation of appropriate treatment. The possible mechanisms responsible for this uncommon association are discussed.

Adult↗
PubMed1988

In vitro selectivity of agonists and antagonists for beta 1- and beta 2-adrenoceptor subtypes in rat brain.

A radioreceptor binding assay was developed to determine the selectivity of beta-adrenoceptor agents in rat brain. This was achieved by using the highly selective unlabelled antagonists CGP 20712A and ICI 118-551 to block beta 1- or beta 2-sub-populations respectively in rat cerebral cortex membranes. This permitted the selective labelling of beta-adrenoceptors with the antagonist (-)-[125I]pindolol. Using this method, compounds could be routinely screened and selectivity profiles for binding in the CNS determined with a high degree of sensitivity and resolution.

Adrenergic beta-Agonists↗
PubMed1988

[Anal plasty after excision of giant condyloma acuminata].

Giant condyloma acumination, also called Bürschke-Loewenstein disease, is a pseudo-tumoral epithelial proliferation of viral origin (human papilloma virus). Surgery is the most effective of all treatments, but it results in loss of all tissues covering the anal canal. We suggest a reconstruction technique, performed under colostomy, in which the rectal mucosa is brought down and three sliding flaps are constructed from the skin of the ischio-anal fossae.

Anal Canal↗
PubMed1988

Insertional translocations: report of two new families and review of the literature.

We describe two families with insertional translocations. In the first, a large family ascertained because of repeated pregnancy loss, the insertional translocation, ins(1;3)(q32;p13pter), was found to be segregating through three generations. In the second family, ascertained through a proposita with congenital malformations, multiple spontaneous abortions also occurred. The father had an insertional translocation, inv 4(p14,q21.1)ins(7,4)(q32;q21.1 q23). These cases illustrate that recurrent fetal wastage may be caused by insertional translocations and in fact may be the only clinical manifestation of this unusual type of chromosome rearrangement.

Chromosomes, Human, Pair 1↗