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T Francis

Publications and source records attributed to T Francis.

At least 19 recordsLinked to original sources
PubMed2003

The ex-vivo-shunt-model: novel approach for assessing the thrombogenicity of vascular implants.

OBJECTIVE: Disadvantages associated with commercially available vascular implants necessitate alternative strategies to develop new vascular prostheses. Although many tissue characterizing strategies have been defined, no valid test for thrombogenicity exists. Here we introduce a novel concept for thrombogenicity testing of vascular implants METHODS: Silastic tubes were implanted into the carotid arteries of 12 sheep. After placing these shunts, tc99m-labeled platelets were administered and test-vessels were put in between the shunts. Native autologous (n=6), as well as native/acellularized allogeneic (n=6/n=6), and xenogeneic (n=6/n=6) carotid arteries and allogeneic (n=6/n=6) and xenogeneic (n=6/n=6) carotid arteries reseeded with allogeneic endothelial-cells, fibroblasts and myocytes were evaluated. Number and time course of intra-operatively deposited platelets were evaluated with a Geiger-counter; certain areas of platelet deposition located, envisioned and characterized by a gamma-camera and scanning electron-microscopy afterwards. RESULTS: Counter results revealed no significant different platelet depositions when comparing silastic tubes with either autologous or allogeneic native carotid arteries. However, starting 5 minutes after placement, acellularized/reseeded allogeneic (p=0.001/p=0.00004), and xenogeneic (p=0.0001/p=0.01) carotid arteries showed significantly more platelet depositions than native autologous carotides. Moreover, it was possible to show that almost no platelets adhere to native vessels or silastic tubes, thus proving the test method itself. CONCLUSION: The Ex-Vivo-Shunt-Model is a valid method to measure and envision the intrinsic thrombogenicity of vascular implants.

Anastomosis, Surgical↗
PubMed2001

American ginseng (Panax quinquefolius L.) attenuates postprandial glycemia in a time-dependent but not dose-dependent manner in healthy individuals.

BACKGROUND: We previously showed that 3 g American ginseng administered 40 min before an oral glucose challenge significantly reduces postprandial glycemia in subjects without diabetes. Whether this effect can be replicated with doses <3 g and administration times closer to the oral glucose challenge is unclear. OBJECTIVE: Our objective was to study the dosing and timing effects of American ginseng on postprandial glycemia. DESIGN: In a random crossover design, 12 healthy individuals [X +/- SEM age: 42 +/- 7 y; body mass index (BMI; in kg/m2): 24.1 +/- 1.1] received 16 treatments: 0 (placebo), 1, 2, or 3 g American ginseng at 40, 20, 10, or 0 min before a 25-g oral glucose challenge. Capillary blood was collected before administration and at 0, 15, 30, 45, 60, and 90 min after the start of the glucose challenge. RESULTS: Two-way analysis of variance showed that the main effects of treatment and administration time were significant (P < 0.05). Glycemia was lower over the last 45 min of the test after doses of 1, 2, or 3 g ginseng than after placebo (P < 0.05); there were no significant differences between doses. The reductions in the areas under the curve for these 3 doses were 14.4 +/- 6.5%, 10.6 +/- 4.0%, and 9.1 +/- 6%, respectively. Glycemia in the last hour of the test and area under the curve were significantly lower when ginseng was administered 40 min before the challenge than when it was administered 20, 10, or 0 min before the challenge (P < 0.05). CONCLUSIONS: American ginseng reduced postprandial glycemia in subjects without diabetes. These reductions were time dependent but not dose dependent: an effect was seen only when the ginseng was administered 40 min before the challenge. Doses within the range of 1-3 g were equally effective.

Adult↗
PubMed2000

American ginseng (Panax quinquefolius L) reduces postprandial glycemia in nondiabetic subjects and subjects with type 2 diabetes mellitus.

BACKGROUND: Despite a lack of medical evidence to support its therapeutic efficacy, the use of herbal medicine has increased considerably. Ginseng, one of the most widely used herbs, is hypothesized to play a role in carbohydrate metabolism and diabetes mellitus. We therefore undertook a preliminary short-term clinical study to assess whether American ginseng (Panax quinquefolius L) affects postprandial glycemia in humans. DESIGN: On 4 separate occasions, 10 nondiabetic subjects (mean [+/-SD] age, 34+/-7 years; mean [+/-SD] body mass index [BMI], 25.6 +/- 3 kg/m2) and 9 subjects with type 2 diabetes mellitus (mean [+/-SD] age, 62 +/- 7 years; mean [+/-SD] BMI, 29 +/- 5 kg/m2; mean [+/-SD] glycosylated hemoglobin A1c, 0.08+/-0.005) were randomized to receive 3-g ginseng or placebo capsules, either 40 minutes before or together with a 25-g oral glucose challenge. The placebo capsules contained com flour, in which the quantity of carbohydrate and appearance matched the ginseng capsules. A capillary blood sample was taken fasting and then at 15, 30, 45, 60, 90, and 120 (only for subjects with type 2 diabetes mellitus ) minutes after the glucose challenge. RESULTS: In nondiabetic subjects, no differences were found in postprandial glycemia between placebo and ginseng when administered together with the glucose challenge. When ginseng was taken 40 minutes before the glucose challenge, significant reductions were observed (P<.05). In subjects with type 2 diabetes mellitus, the same was true whether capsules were taken before or together with the glucose challenge (P<.05). Reductions in area under the glycemic curve were 18%+/-31% for nondiabetic subjects and 19+/-22% and 22+/-17% for subjects with type 2 diabetes mellitus administered before or together with the glucose challenge, respectively. CONCLUSIONS: American ginseng attenuated postprandial glycemia in both study groups. For nondiabetic subjects, to prevent unintended hypoglycemia it may be important that the American ginseng be taken with the meal.

Adult↗
PubMed2000

Multiresidue screen for cardiotoxins by two-dimensional thin-layer chromatography.

A two-dimensional thin-layer chromatographic method was developed for the qualitative determination of the cardiotoxins oleandrin, gitoxin, digitoxin, gitoxigenin, and grayanotoxins I, II, and III in gastrointestinal contents (stomach, rumen, colon, and cecum contents), feces, and plant material. The cardiotoxins were extracted with dichloromethane. The extract was cleaned up by charcoal and reverse phase solid-phase extraction columns. Analysis was performed by two-dimensional thin-layer chromatography on silica gel plates and visualized by aluminum chloride followed by chloramine T spray. The method detection limits were 0.05 microg/g for oleandrin, 0.1 microg/g for gitoxin, and 0.2 microg/g for the other toxicants in gastrointestinal contents and feces and were 5 times higher in plant material. Four replicate fortifications of bovine rumen contents, bovine feces, and alfalfa at these levels were all well recovered. The diagnostic utility of the method was tested by analyzing samples submitted to the veterinary toxicology laboratory.

Animals↗
PubMed1998

Blue-green algae toxicosis in cattle.

Twenty-four of 175 heifers died after ingesting water from a stock pond containing blue-green algae (genus Microcystis) in southern Colorado. Affected cattle were found dead or had signs of nervousness, and were recumbent, weak, anorectic, and hypersensitive to noise when first examined. All cattle died within 3 days after the onset of signs. At necropsy, the rumen contained blue-green algae, and the liver was larger than normal, friable, and dark red. The most important histologic lesion was hepatocyte degeneration and necrosis. Intraperitoneal administration of lyophilized cell material from the bloom caused hepatic necrosis and death in mice, and water from the pond had clumps of cells surrounded by a clear calyx, consistent with the appearance of organisms of the genus Microcystis. Samples of pond water were examined by means of high-pressure liquid chromatography; microcystin-LR, one of the hepatotoxins produced by Microcystis spp, was found. Chromatography may be useful in the diagnosis of blue-green algae toxicosis.

Animals↗
PubMed1997

Immune responses during pregnancy and the development of allergic disease.

It is now established that allergen exposure in the first few months of life is important in the development of specific allergic sensitisation (1, 2). Furthermore, the immune response of infants born to families with a strong history of allergic disease is relatively immature at birth in comparison to infants with no family history of allergies, with reduced production of Interferon-gamma (IFN-gamma) (3-5) and lower levels of T cell activation and memory (6). It therefore seems logical that the interaction of these two factors must be important in the ontogeny of allergic disease.

Allergens↗
PubMed1992

Common thyroid disorders in the elderly.

Thyroid disease in the elderly is common but often has an insidious onset with symptoms that mimic those of normal aging. Understanding the significance of thyroid function test results requires an appreciation of the normal physiologic variations of aging and the complicating effects of diseases and medications; only then can one accurately discriminate between various disease processes, order additional appropriate tests, and deliver rational management. The increasing prevalence of thyroid disorders with age, coupled with the current and future dramatic growth of the elderly population, demands that primary care providers be vigilant to the likelihood of thyroid disease and informed as to its most proper, expedient, and cost-effective diagnosis and management.

Age Factors↗
PubMed1991

Lymphocytes express thyrotropin receptor-specific mRNA as detected by the PCR technique.

Human lymphocytes are known to play a critical role in autoimmune diseases both by producing antibodies and by participating in lymphokine-cellular interactions. TSH, a classic pituitary hormone, may be secreted by human lymphocytes, and controversy has existed whether a specific, authentic TSH receptor also was present on the surface of these cells. The objective of our study was to identify TSH receptor transcripts after designing specific oligonucleotides that would recognize a unique putative TSH binding area of the thyroidal TSH receptor. The existence of TSH receptor transcripts was probed by employing these primers in a PCR reaction with cDNA derived from normal peripheral human lymphocytes and human thyroid tissue, as well as with cDNA from a medullary cancer cell line and rat liver. Human lymphocytes and thyroid tissue, but not medullary cancer cells or rat liver, demonstrated specific TSH receptor amplification product both by ethidium bromide staining and by Southern blot hybridization with labeled TSH receptor cDNA. The lymphocyte cDNA was partially sequenced and found to be identical to the thyroid-derived cDNA. These findings indicate that normal, nonactivated, human lymphocytes produce transcript for a TSH receptor that appears identical to that in thyroid tissue. Future studies should focus on the regulation of this transcript, as well as on the role TSH and TSH receptor may play in modulating local lymphokine activation of T and B cells, both in normal conditions and in autoimmune thyroid disease.

Base Sequence↗
PubMed1987

An in vitro study of immunomodulatory effects of some saponins.

The in vitro immunomodulatory activities of a number of saponins (crude Quillaja saponin, Quillayanin, Quil-A and glycyrrhizic acid) are described. Addition of these saponin preparations to mouse spleen cell cultures resulted in significant cell proliferation. B-cells were induced to proliferate in the presence of the crude saponin, and T-cells in the presence of Quil-A. On the other hand, Quillayanin and glycyrrhizic acid stimulated both T- and B-lymphocytes equally. The selective proliferation of subtypes of lymphocytes correlated with restimulation responses by polyclonal mitogens. Pretreatment by lymphocytes with crude saponins induced significant T-cell responses to PHA and Con A, and to T-independent B-cell stimulation by LPS. Pulse exposure of spleen cells to Quil-A resulted in enhanced cell proliferation when restimulated with PHA, Con A and PWM. In comparison, similar exposure of lymphocytes to Quillayanin or glycyrrhizic acid produced markedly increased responses to PHA, Con A, PWM and LPS. Incubation of lymphocytes in the presence of Quillaja saponins and Quillayanin caused effector cell generation as determined in a one-way mixed lymphocyte reaction. In the case of lymphocytes cultured in the presence of crude saponins or glycyrrhizic acid, the supernatants contained active soluble factors. This was demonstrated by the observation that the addition of supernatants to spleen cell cultures induced spontaneous cell proliferation, and also amplified their responses to a suboptimal dose of PHA. The experimental data suggest that different components in the Quillaja saponin preparations may have selective effects on various subtypes of cell populations. Glycyrrhizic acid has the most profound immunomodulatory activity in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

ELISA today.

Explore the source record for details and available documents.

Antibodies↗
PubMed1985

Vitamin A and E content of human milk at early stages of lactation.

The influence of gestational age and lactational stage on carotene, retinol ester, alpha-tocopherol and gamma-tocopherol content of early human milk was studied. These nutrients were analyzed simultaneously using normal phase high-performance liquid chromatography. Serial samples of colostrum and early milk representative of complete early morning expressions were obtained during the first 6 weeks post-partum from mothers giving birth prematurely (PT) and at term (FT). Colostrum carotene content declined significantly during the first week of lactation. There was no apparent gestational age effect on milk carotene levels. The longitudinal pattern of change observed for milk retinol ester and alpha-tocopherol content was however, significantly different between PT and FT milk. Retinol ester levels were similar on days 1-2 postpartum reaching a maximal level on days 3-4 postpartum in FT milk. For PT milk the maximum retinol ester concentration occurred on days 6-7 postpartum. Retinol ester content decreased throughout lactation. The rate of decline was more marked for FT milk. The concentration of alpha-tocopherol in colostrum was higher in FT milk. On all subsequent days examined the level of alpha-tocopherol was greater in PT milk. For both FT and PT milk the alpha-tocopherol concentration was higher during the first week of lactation when compared with following weeks. gamma-Tocopherol levels were not influenced by gestational age or lactational stage. Levels of milk vitamin A and E did not appear to correlate with maternal intake. Colostrum levels of vitamin A and E may imply active sequestration by the mammary gland in compensation for limited placental transport. Early milk content of vitamin A and E appears to parallel mammary gland lipid synthesis.

Carotenoids↗
PubMed1982

Effect of processing on digestibility and the blood glucose response: a study of lentils.

To test the effect of processing on digestibility and the glycemic response to a leguminous seed, a group of eight healthy volunteers took a series of breakfast test meals containing either lentils which had been processed in four different ways or the same amount of carbohydrate as white bread. Lentils, boiled for 20 min, resulted in a flattened blood glucose response by comparison with bread. This was unaltered by blending the lentils to a paste or boiling them for an additional 40 minutes. However the blood glucose response was significantly enhanced by drying the boiled blended lentils for 12 h at 250 degrees F. In vitro digestion with human saliva showed the rate of sugars released from the food related positively to the blood glucose rise. Breath hydrogen studies indicated that carbohydrate malabsorption was too small to account for differences in the blood glucose response. These results emphasize the importance of processing in determining digestibility and hence the glycemic response to a food.

Blood Glucose↗
PubMed1969

Interpretations of influenza antibody patterns of man.

The age distribution of antibodies to A2/Hong Kong/68 influenza virus was ascertained in sera collected before the pandemic of 1968 in order to determine whether Hong Kong-like viruses had previously prevailed in man, and, if so, at what period. The findings indicate that Hong Kong-like viruses were probably involved in outbreaks at or about the turn of the century. The data are interpreted to indicate that antigenic drifting among Asian influenza strains from the A2/Japan/305/57-like variant, believed to be responsible for the pandemic of 1889-90, to the Hong Kong-like variant of 1900, is a phenomenon that has been repeated in recent times. The findings constitute another example of antigenic recycling after a long period of absence, and support the view that the number of antigens of influenza A is finite.

Antibodies↗
PubMed1969

Effect of vaccination of a school-age population upon the course of an A2-Hong Kong influenza epidemic.

Children of school age experience the greatest morbidity in influenza outbreaks and are major disseminators of the virus. On this basis, monovalent A2/Aichi/2/68 vaccine was offered to the schoolchildren of Tecumseh, Michigan, to control the anticipated outbreak of Hong Kong influenza. More than 85% of the children were vaccinated. Systemic reactions were rare and 94.5% of those tested exhibited a 4-fold or greater rise in HI titre.The occurrence of respiratory infections in the subsequent outbreak was followed in Tecumseh and the neighbouring unvaccinated community of Adrian, Michigan. Hong Kong influenza virus was isolated during a 10-week period, and, during this time the mean rate of illness in Adrian was 3.0 times higher than in Tecumseh. The protection from illness in Tecumseh was not limited to the vaccinated children; all age-groups experienced lower rates of respiratory infection. Thus vaccination of schoolchildren was shown to produce a marked lowering of illness rates in an entire community.

Adolescent↗
PubMed1969

Laboratory and clinical characteristics of attenuated strains of influenza virus.

Prior to 1967, attenuation of influenza virus was achieved by gradually lowering the incubation temperature until optimal growth at 25 degrees C was obtained. The process of attenuation of a Hong Kong strain was modified and considerably shortened. The temperature of incubation was changed abruptly from 35 degrees C to 25 degrees C and a cold variant was selected using the plaque-assay system.A set of genetic markers was developed for assessing the potential virulence of cold-passaged variants. The cold variant of the Hong Kong strain was temperature-sensitive, acid-labile and produced a small plaque in primary chick kidney cells incubated at 35 degrees C. Additional differentiating biological properties relating to the adaptation of the virus to growth at 25 degrees C and to loss of virulence in a susceptible host are presented.The cold-adapted variant was found to be relatively avirulent and highly antigenic for mice and ferrets, and virus was recovered from the nasopharynx of infected ferrets during the first 3 days. The virus recovered was still unable to grow well at 41 degrees C (rct/41-), was sensitive to acid pH and produced small plaques at 35 degrees C and larger ones at 25 degrees C.After a series of plaque purifications, the cold variant showed further loss of virulence to mice, more vigorous growth at 25 degrees C, complete failure to grow at 41 degrees C and good antigenic potency.The genetic markers were stable in the plaque-purified cold variant after at least 10 consecutive passages either in tissue culture at 35 degrees C, or in mice.Cold variants of type B influenza virus have a narrower range of temperature sensitivity compared with type A strains. Reduced plaquing efficiency and reproductive capacity occurred at 35 degrees C (rct/35-) with the attenuated type B strains instead of at 41 degrees C as with the type A strains.Clinical trials with the attenuated Hong Kong strain of influenza virus (A2/Aichi/2/68) have demonstrated the acceptability and immunogenicity of the strain in man.

Animals↗