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Biomedical subjects

T Horn

Publications and source records attributed to T Horn.

At least 163 records · Page 9Linked to original sources
PubMed1990

The fate of transplanted encapsulated islets in spontaneously diabetic BB/Wor rats.

The present study was undertaken to determine whether the transplantation of encapsulated MHC identical islets into diabetic BB/Wor/BB rats could cure their diabetes. Islets were isolated from diabetes-resistant BB/Wor/WB rats and encapsulated in alginate-polylysine-alginate membranes. Five thousand islets were transplanted into the peritoneal cavity of spontaneously diabetic BB/Wor/BB rats (n = 9) that had been insulin dependent for more than five weeks. Similar diabetic animals were transplanted with 5,000 unencapsulated islets (n = 10) or with empty capsules (n = 3). After transplantation of free islets, the animals reverted to the insulin-dependent state after a median of 16 days (17 +/- 4 days, mean +/- SEM). After transplantation of encapsulated islets, the animals reverted to the diabetic state after a median of 59 days (54 +/- 10 days, mean +/- SEM). Light microscopic and electron microscopic analyses of capsules recovered from the peritoneal cavity after failure of graft function showed no evidence either of lymphocytic invasion of the capsules or of specific destruction of the islets. The capsules were, however, overgrown by a layer of histiocytes and numerous layers of fibroblasts. Empty capsules recovered after 15 and 60 days were overgrown to the same extent.

Alginates↗
PubMed1989

Forks and combs and DNA: the synthesis of branched oligodeoxyribonucleotides.

Nucleoside phosphoramidite derivatives containing two protected primary hydroxyl functions have been incorporated into synthetic oligonucleotides as 'branching monomers'. With selective deprotection, multiple identical copies of an additional oligonucleotide can be incorporated to form fork- or comb-like structures for use as signal amplification materials in nucleic acid hybridization assays.

Gene Amplification↗
PubMed1989

Tubuloreticular inclusions in skin biopsies from patients with HIV infection.

Skin biopsies obtained from apparently normal skin from 15 HIV infected patients and 6 anti-HIV negative patients were examined by electron microscopy. Tubuloreticular inclusions (TRI) were detected within the cytoplasm of capillary endothelial cells in 5/5 AIDS patients and in 2/5 patients with AIDS related conditions. Biopsies from 5 asymptomatic HIV positive patients and the 6 control subjects were without ultrastructural alterations. The occurrence of TRI was related to low numbers of CD 4+ lymphocytes. 5/7 patients with TRI had elevated serum interferon activity, and in all of the patients without TRI, interferon activity was below detection level. The occurrence of TRI was not dependent on the presence of free p24 antigen in serum. It is concluded that the occurrence of TRI in entothelial cells of skin capillaries is associated with late stages of HIV infection and this may indicate a generalization of this change.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Metastatic malignant melanoma arising from a common blue nevus in a patient with subacute cutaneous lupus erythematosus.

We describe a 66-year-old black male who first presented with subacute cutaneous lupus erythematosus (SCLE) and was later found to have malignant melanoma adjacent to a common blue nevus. The melanoma was located on the left buttock and in several left inguinal lymph nodes. Following complete resection and lymph node dissection the patient developed widespread leukoderma. To our knowledge this is the first report of malignant melanoma arising in a common blue nevus. The literature on SCLE and leukoderma in the setting of melanoma is reviewed.

Aged↗
PubMed1989

Possible role of IL-1, TNF-alpha, and IL-6 in insulin-dependent diabetes mellitus and autoimmune thyroid disease. Thyroid Cell Group.

Recent experiments indicate a central role of macrophages (M phi), and natural killer (NK) cells, and their products IL-1, IL-6 and TNF alpha in autoimmune endocrine diseases. Intermediate levels of IL-1 alpha/beta inhibit the function of pancreatic beta-cells and thyrocytes, an effect potentiated by TNF alpha. In contrast, low levels of IL-1 potentiate the secretion of insulin and thyroid hormones, and intermediate levels of IL-6 double glucose-induced insulin production by beta-cells. Intermediate and high levels of IL-1 and IL-6 are cytotoxic to normal beta-cells. IL-1 induces IL-6 in isolated islets and in thyrocytes. The cytokines may play a role in the physiological regulation of endocrine functions, for instance during conditions of stress. The genes for TNF alpha and -beta, both located in the MHC region, and IL-6 are polymorphic, and specific alleles may control the amount of cytokine produced. Specific TNF alpha/beta alleles may be in linkage disequilibrium with HLA alleles known to be positively or negatively associated with endocrine and other autoimmune diseases.

Animals↗
PubMed1988

Solid supported hydrolysis of apurinic sites in synthetic oligonucleotides for rapid and efficient purification on reverse-phase cartridges.

Rapid purification methods for synthetic oligonucleotides involving reverse-phase cartridges (RPC) and enzymatic hydrolysis have been introduced. These methods are based on a discrimination between the desired target fragment protected with a 5'-DMT group and incompletely elongated products possessing a 5'-hydroxyl function. For target products over 60 nucleotides, the rapid methods are of little use as reported to date. We have found that the problem is due to the presence of truncated 5'-DMT fragments generated from apurinic sites within the target product during NH4OH deprotection. These side products are co-purified with the target fragment when the rapid purification procedures are employed. If a step is included during deprotection to cleave the apurinic sites prior to removal of the crude product from the solid support (1 M lysine-HCl, pH 9 for 90 min at 60 degrees C), fragments up to 118 bases can be purified by RPC to near homogeneity.

Apurinic Acid↗
PubMed1988

Fibronectin as predictor of cirrhosis in men who abuse alcohol.

In a study of 142 male alcohol abusers without evidence of cirrhosis the presence of intralobular fibronectin in the liver was investigated in relation to the subsequent development of the disease. All 142 initial biopsy samples showed preserved architecture. During a follow up period of 10-13 years 23 patients (16%) developed cirrhosis. Twelve of 110 patients with normal or slightly increased amounts of parenchymal fibronectin in the initial biopsy specimen developed cirrhosis, whereas eight out of 27 patients with moderately increased amounts and three out of five with significantly increased amounts later developed the disease (p less than 0.005). Semiquantitative assessment of the amount of parenchymal fibronectin at an early stage of alcoholic liver disease is of definite predictive value for the development of cirrhosis.

Alcoholism↗
PubMed1988

A comparison of non-radioisotopic hybridization assay methods using fluorescent, chemiluminescent and enzyme labeled synthetic oligodeoxyribonucleotide probes.

N4-[N-(6-trifluoroacetylamidocaproyl)-2-aminoethyl]-5'-O-dimethoxy trityl -5-methyl-2'-deoxycytidine-3'-N,N-diisopropyl-methylphosphoramidite++ + has been synthesized. This N4-alkylamino deoxycytidine derivative has been incorporated into oligonucleotide probes during chemical DNA synthesis. Subsequent to deprotection and purification, fluorescent (fluorescein, Texas Red and rhodamine), chemiluminescent (isoluminol), and enzyme (horseradish peroxidase, alkaline phosphatase) labels have been specifically incorporated. Detection limits of the labels and labeled probes were assessed. Also, the detection limits and nonspecific binding of the labeled probes in sandwich hybridization assays were determined. The enzyme modified oligonucleotides were found to be significantly better labeling materials than the fluorescent or chemiluminescent derivatives, providing sensitivities comparable to 32P-labeled probes.

Alkaline Phosphatase↗
PubMed1988

[Injuries caused by stingrays].

We report on an injury caused by the bite of a South American freshwater stingray. Although wide excision is the therapy of choice, prolonged healing must be expected. We give some information on the mode of injury and biological data regarding the genus protamotrygon. This stingray may also be bred in aquariums.

Animals↗
PubMed1988

Light microscopical demonstration and zonal distribution of parasinusoidal cells (Ito cells) in normal human liver.

The parasinusoidal cells of the liver (Ito cells) were demonstrated light microscopically in autopsy specimens fixed in formalin and stained with Oil red O after dichromate treatment. The method allows examination of large samples containing numerous acini. Quantitative assessment showed a zonal gradient with 6.3 and 7.7 parasinusoidal cells per 62.5 X 10(3) micron2 in zone 1 and 3, respectively.

Aged↗
PubMed1988

Perivenous and perisinusoidal collagen content in the acinar zone 3 in the "normal" liver. A light microscopical study.

The thickness of the terminal hepatic vein wall (TTHV) and the content of perisinusoidal collagen in 989 zone 3 areas in Picro-Sirius-stained sections from 117 liver biopsies with normal morphology or slight non-specific changes were analyzed. TTHV varied from 0.4 micron to 21.3 microns (median 3.8 microns). A positive correlation was found between TTHV and the diameter of the terminal hepatic vein. The average TTHV of the individual biopsies was not correlated to age, sex or liver morphology. The average zone 3 collagen content did not exceed that of zones 2 and 1, with the exception of biopsies with slight steatosis, where a minimal increase in zone 3 collagen was found. The normal variability of TTHV and the correlation to the diameter of THV must be considered in the evaluation of perivenular fibrosis. Even a slight increase in perisinusoidal collagen content may be suggestive of a pathological condition.

Adult↗
PubMed1988

The occurrence and significance of fibronectin in livers from chronic alcoholics. An immunohistochemical study of early alcoholic liver injury.

The occurrence and distribution of fibronectin (FN) was assessed by an immunoperoxidase technique in liver biopsies from alcoholics without and with acinar zone 3 fibrosis of varying degrees. Increased amounts of FN was found diffusely in zone 3 areas with a perisinusoidal and pericellular localization. FN was closely correlating to the pattern of fibrosis but increased amounts of FN could also be seen in biopsies without fibrosis as visualized in Picro-Sirius stained sections. There was no topographical relationship to liver cells with fatty changes, Mallory bodies or to alcoholic hepatitis. It is made probable that FN is of significance in the development of early liver fibrosis in alcoholics and that FN may act as a chemotactic factor for collagen producing cells and as a skeleton for the new collagen formation.

Fibronectins↗
PubMed1987

Megamitochondria as a diagnostic marker for alcohol induced centrilobular and periportal fibrosis in the liver.

One hundred and five biopsies with centrilobular and/or portal/periportal fibrosis of different aetiology were examined by light microscopy for the presence of megamitochondria (MM). Sixty eight patients had some daily alcohol intake, 37 did not. The incidence of MM in the group with daily alcohol consumption was 49% and in the group without only 5%. Two types of MM were identified. Type I MM (round to oval) were located mainly in zone 3 and type II (needle-shaped) mainly in zone 1. Both types were related to alcoholic liver disease.

Alcohol Drinking↗
PubMed1987

A novel method for the rapid detection of specific nucleotide sequences in crude biological samples without blotting or radioactivity; application to the analysis of hepatitis B virus in human serum.

The detection of a little as 0.2 pg (60,000 molecules) of hepatitis B viral (HBV) DNA in human serum samples in 4 h has been demonstrated using a solution-hybridization and bead-capture method. An amplification method based on chemically crosslinked oligodeoxyribonucleotides was coupled with a horseradish peroxidase-labeling scheme for the ultimate detection of the analyte. Two sets of HBV complementary synthetic oligodeoxyribonucleotide probes containing one of two types of single-stranded (ss) overhangs were employed. These ss overhangs were used to capture the probe-analyte complex onto a bead and subsequently to label it. Detection was achieved with either a chemiluminescent or colorimetric output substrate for the enzyme. Only in the presence of the virus was label specifically bound to the support. The assay was relatively unaffected by either sample composition or by the presence of heterologous nucleic acids.

Base Sequence↗
PubMed1987

Portal tract lipogranulomas in liver biopsies.

Portal lipogranulomas in liver biopsy specimens were investigated. The incidence of biopsies containing portal lipogranulomas was 2.4%. Out of 20 biopsies with lipogranulomas 10 biopsies contained only one lipogranuloma. Portal lipogranulomas show a distinctive morphology with fat vacuoles surrounded by macrophages. They are consistently found together with parenchymal steatosis and probably originate from parenchymal fat being transported to portal tracts. Portal lipogranulomas are of importance in the differential diagnosis from other granulomas.

Biopsy↗