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Biomedical subjects

E Tamm

Publications and source records attributed to E Tamm.

At least 19 recordsLinked to original sources
PubMed2001

Advanced 3-D imaging for the evaluation of pancreatic cancer with multidetector CT.

BACKGROUND: Pancreatic cancer remains the fourth leading cause of cancer-related death. Surgery is the only option for cure. Multidetector computed tomography (CT) and advanced postprocessing techniques, can provide solutions for difficult problems in diagnosing and staging disease, and can aid radiologists in communicating findings to surgeons and oncologists. Multiplanar reformats can provide additional information on involvement of the portal vein, hepatic artery, and common bile duct. Maximum intensity projection (MIP) images and volume rendered images can aid in identification of important vascular variants. MIP images can show the relationship of tumor to the pancreatic duct or biliary tree. Curved reformatted images can show the relationship of tumor to the pancreatic duct or vascular structures.

Humans↗
PubMed1999

A picture archiving and communications system featuring multiple monitors using Windows98.

We present an effective approach to manage, review, and distribute Digital Imaging and Communications in Medicine (DICOM) images with multiple monitors using Windows98 (Microsoft Corp, Redmond, WA) that can be implemented in an office-based setting. Computed tomography (CT), magnetic resonance imaging (MRI), and angiographic DICOM images were collected, compressed, and stored using Medweb (Medweb, Inc, San Francisco, CA) software. The Medweb server used the Linux/UNIX operating system on a Pentium 333-MHz processor with 128 MB of RAM. Short-term storage capacity was about 2 weeks with routine usage of an 11-GB hard drive. Images were presented for reading on a dual-monitor Windows98 Pentium display station with 160 MB of RAM using a Medweb/Netscape (Netscape Communications Corp, Mountain View, CA) viewer. There was no significant discrepancy in diagnosis between electronic and conventional film images. Mean reading time for 32 cases was 118 seconds. The Medweb JAVA plug-in viewer loaded the first image within 30 seconds of selecting the case for review. Full uncompressed 16-bit images allowed different window settings to better assess for pathology. Multiple monitors allowed viewing various hanging protocols. Cine viewing was also possible. Key diagnostic images were electronically transmitted to referring physicians. On-call radiologists were able to access images through the Internet. By combining Medweb, DICOM, and web-browser software using desktop personal computers (PCs), an easily accessible picture archiving and communications system (PACS) is available to radiologists and referring physicians. Multiple monitors are easily configured and managed using Windows98. This system can sustain changes and can be extended to provide variable functions using inexpensive PCs.

Angiography↗
PubMed1999

Safety and immunogenicity of combined Dtpa-IPV vaccine for primary and booster vaccination.

This study evaluated the safety and immunogenicity of combined diphtheria, tetanus, acellular pertussis, inactivated poliomyelitis vaccine (DTPa-IPV) given as primary immunization at ages 3, 4.5 and 6 months and a booster dose between the ages of 18 and 27 months to healthy children. The acellular pertussis tricomponent vaccine contains pertussis toxoid (PT), filamentous haemaglutinin (FHA) and 69 kDa outer membrane protein (PRN). Serum immune responses to the administered antigens were measured before and after the primary and the booster vaccination series. The safety of the vaccine was evaluated based on diary cards completed by parents within 4 d following each vaccination. A total of 237 and 150 children completed the primary and booster vaccination series, respectively. A total of 483 (66.5%) and 111 (74%) local and 317 (43.7%) and 98 (65.3%) general adverse events were reported after 726 doses of the primary series and 150 of the booster doses, respectively. Compared with primary vaccination, the incidence of all adverse symptoms was greater after the booster dose and a previous severe reaction was a risk factor for a severe reaction after the booster dose (OR = 5.11). All but 1 child, who failed to have antibodies to diphtheria toxoid after the booster dose, responded to all administered antigens with antibody titres greater than the assay cut-off points. The combined DTPa-IPV used for primary and booster immunization induced good immunity, but was associated with large local reactions in 21.3% of children after the booster dose.

Antibodies, Bacterial↗
PubMed1994

Characterization of muscarinic receptor involvement in human ciliary muscle cell function.

Muscarinic agonist-induced contraction of the ciliary muscle is generally believed to increase aqueous outflow facility and effect accommodation. We used cultured human ciliary muscle cells as a model to study the muscarinic receptor subtype(s) involved in the contractile response of the muscle. Thus, a single cell contraction assay for these muscle cells was developed. And since agonist-induced contraction of smooth muscles is expected to involve the activation of phospholipase C (PLC), we also monitored the PLC activity in these cells. Carbachol caused contraction of the muscle cells in a dose-dependent and time-dependent manner with an estimated EC50 of 1-3 microM. The contractile effect of 100 microM carbachol was antagonized by pretreatment of atropine (1 microM) and 4DAMP (10 nM, antagonist selective for the M1 and M3 receptors) but not by pirenzepine (10 microM, antagonist selective for the M1 receptor), suggesting the involvement of the M3 but not the M1 muscarinic receptor. M3 receptor is also essential for the carbachol-induced PLC activation in the ciliary muscle cells, as indicated by the activity profiles of receptor subtype selective antagonists. For example, the stimulative effect of carbachol (EC50 = 20 microM) was antagonized by pirenzepine (pKi = 6.8), HHSiD (pKi = 7.6), 4DAMP (pKi = 9.5) and methoctramine (pKi < 6). Thus, these results indicate that an M3-like receptor subtype is essential in mediating the muscarinic agonists-induced functional changes, such as PLC activation or muscle contraction, in the ciliary muscle.

Atropine↗
PubMed1994

Immunohistochemical characterization of the 'intimal proliferation' phenomenon in Sneddon's syndrome and essential thrombocythaemia.

Cellular changes were immunocytochemically characterized in skin vessels of five patients with idiopathic generalized racemose livedo (Sneddon's syndrome), and one patient with localized racemose livedo associated with essential thrombocythaemia. Antibodies against alpha-smooth muscle-actin, tropomyosin, desmin, vimentin, factor VIII-related antigen, human endothelial cells (CD31), human macrophages (CD68), and HLA-DR positive cells (CR3/43) were used. Conventional light microscopy showed, in all cases, intimal thickening of ascending arteries and arterioles as a result of an accumulation of cells and extracellular hyalinized material. None of the specimens showed infiltration with polymorphonuclear leucocytes or macrophages. The cells in the region of the intimal hyperplasia showed intense positive immunostaining for alpha-smooth muscle actin and tropomyosin. Staining for the intermediate filament desmin was localized to the resident smooth muscle cells of the media, whereas staining for vimentin was found in all types of cells in both the intima and media. Positive immunostaining for factor VIII-related antigen and CD31 was strictly confined to the endothelial cells lining the narrowed lumina of the vessels. No positive staining with either antibody was observed in totally occluded vessels. Cells in the subintimal space did not show reactivity for CD68 in any of the specimens, but two cases showed solitary cells with positive staining for HLA-DR in this region. There were no differences in staining pattern between Sneddon's syndrome and essential thrombocythaemia with any of the antibodies. Our results support the assumption that the 'intimal proliferation' in both diseases is caused by colonization of the subendothelial space with contractile cells of possible smooth muscle origin.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1993

[Immunocytochemical and ultrastructural studies of human scleral spur. Characterization of a contractile cell population].

Contraction of the ciliary muscle induced by cholinergic drugs causes movement of the scleral spur and separation of the trabecular meshwork lamellae. The effect of epinephrine, however, does not seem to be mediated by ciliary muscle tone. We investigated the scleral spur in 37 human eyes (age 17-87 years). Serial tangential sections were studied with ultrastructural and immunocytochemical methods. The ciliary muscle cells do not enter the scleral spur, but their tendons, which consist of elastic fibers, are continuous with the elastic fibers in the scleral spur. Within the scleral spur is found a population of circularly oriented and spindle-shaped cells. The scleral spur cells form no bundles, but are loosely aggregated. They have long cytoplasmic processes and are connected to each other by adherence type and gap junctions. The scleral spur cells show intense staining for smooth-muscle-specific alpha-actin and myosin. Ultrastructurally, the scleral spur cells contain abundant actin filaments, but otherwise do not show the typical ultrastructure of ciliary muscle cells. The scleral spur cells do not express a complete basal lamina. They form individual tendinous connections with the elastic fibers in the scleral spur, which are continuous with the elastic fibers of the trabecular meshwork. The scleral spur cells are in close contact with nerve terminals containing small granular vesicles that are typical for adrenergic terminals. We conclude that the scleral spur cells are contractile myofibroblasts. Their contraction might be involved in the effects of epinephrine on the aqueous outflow.

Adolescent↗
PubMed1993

Single-cell contraction assay for human ciliary muscle cells. Effect of carbachol.

PURPOSE: The authors developed an assay to observe the contraction of a single human ciliary muscle cell. METHODS: Cultured human ciliary muscle cells were partially detached from the culture dish by incubation with a nonenzymatic dissociation buffer and treated with carbachol or pilocarpine. Contraction was quantified by measuring the cross-sectional surface areas of the cells. RESULTS: Carbachol decreased the cell surface area in a time-dependent manner. Contraction was observed within 1 min after the addition of carbachol and completed in less than 15 min. The effect of carbachol was dose dependent. For example, at 10 min after treatment with 10 mumol/l carbachol, the relative surface areas of cells decreased to 47% +/- 4% (mean +/- standard error of the mean, n = 7, with surface area at 0 min defined as 100%). The relative surface areas were 74% +/- 4% (n = 7) after 1 mumol/l and 100% +/- 9% (n = 7) after 0.1 mumol/l carbachol treatment. This contractile effect was antagonized by pretreatment with atropine, a specific muscarinic antagonist. CONCLUSIONS: A simple method was established to study the functional changes of human ciliary muscle cells.

Biological Assay↗
PubMed1992

Age-related loss of ciliary muscle mobility in the rhesus monkey. Role of the choroid.

Ciliary muscle topography was studied in rhesus monkey eyes (aged 6 to 29 years) bisected meridionally through cornea and optic nerve head. Half of each eye was incubated in atropine sulfate, the other in pilocarpine hydrochloride, and both were then processed for histologic study. Several ciliary muscle sections from the original cut margin and the middle of the half eyes were traced and compared quantitatively. In sections from the middle, where the attachments of the muscle were presumably intact, the pilocarpine effect on ciliary muscle topography was lost with age. In sections near the cut margin, where some of the posterior attachments were disrupted and the choroid had detached from the sclera, the pilocarpine effect persisted with age. These findings suggest that loss of ciliary muscle movement with age is caused by decreased compliance of its posterior attachment.

Aging↗
PubMed1992

Increase in types IV and VI collagen in cherry haemangiomas.

The capillaries in cherry haemangiomas show perivascular hyalinized sheaths. In order to clarify the nature of this sheath material, the extracellular matrix of cherry haemangiomas from 20 normal volunteers (age range 30-64 years) was investigated using immunohistochemical and electronmicroscopical methods. Antibodies against collagen types III, IV and VI and laminin were used. Hyaluronic acid was visualized using the hyaluronic acid binding region of the cartilage proteoglycan as ligand. Electronmicroscopically, the sheaths contained multilaminated basement membrane-like material, collagen fibres 20-25 nm thick with a periodicity of 67 nm and broad-banded aggregates with a periodicity of 100 nm (zebra bodies or fibrous long-spacing fibres). Immunohistochemically, type IV collagen was stained throughout the whole sheath material. Staining for laminin was more confined to the endothelial side of the sheath. Intense staining for type III collagen and hyaluronic acid was found in the connective tissue of the subpapillary layer and between the cherry haemangioma capillaries. Much weaker staining for type III collagen and no staining for hyaluronic acid were found invariably in an area 4-10 microns thick directly around the capillaries. Both sheath material and intercapillary connective tissue of the haemangiomas showed pronounced staining for collagen type VI. Immunogold staining revealed that type VI collagen was localized to microfibrils 5-6 nm thick and to the broad-banded aggregates with 100 nm periodicity. These findings further underline the assumption that the broad-banded aggregates consist of type VI collagen.

Adult↗
PubMed1992

Contractile cells in the human scleral spur.

The scleral spur in 37 human (age 17-87 years) and six cynomolgus monkey eyes (2-4 years) was investigated. Serial meridional and tangential sections were studied with ultrastructural and immunocytochemical methods. The bundles of the ciliary muscle do not enter the scleral spur, but their tendons, which consist of elastic fibres join the elastic fibres in the scleral spur. Within the scleral spur a population of circularly oriented and spindle-shaped cells is found. In contrast to the ciliary muscle cells, the scleral spur cells form no bundles, but are loosely aggregated. They have long cytoplasmic processes and are connected to each other by adherens-type and gap junctions. They stain intensely for alpha-smooth muscle actin, myosin and vimentin. In contrast to the ciliary muscle cells, they do not stain for desmin. Ultrastructurally, the scleral spur cells contain abundant thin (actin) filaments, but do not otherwise show the typical ultrastructural features of ciliary muscle cells. The scleral spur cells do not express a complete basal lamina. They form individual tendinous connections with the elastic fibres in the scleral spur, which are continuous with the elastic fibres of the trabecular meshwork. The scleral spur cells are in close contact with nerve terminals containing small agranular (30-60 nm) and large granular (65-110 nm) vesicles but also with terminals containing small granular (30-60 nm) vesicles which are regarded as typical for adrenergic terminals. We conclude that the scleral spur cells are contractile myofibroblasts. Their contraction might influence the rate of the aqueous outflow.

Adolescent↗
PubMed1992

Age-related changes of the human ciliary muscle. A quantitative morphometric study.

The age-related changes of the ciliary muscle of human eyes (33-87 years) were studied on histological meridional sections. Eighty-five melanoma eyes and 10 eyes of normal donors were investigated. The total area and the length of the muscle, the area of the three main portions and the distance of the inner apex of the muscle to the scleral spur were determined and correlated with age. Total area and length of the muscle show a continuous and significant decrease with age. The area of the longitudinal and reticular portion continuously decreases, whereas the area of the circular portion significantly increases with age. The decrease in area is more pronounced in the longitudinal portion than in the reticular portion of the muscle, which shows an age-related increase in connective tissue. In addition, the distance of the inner apex of the muscle to the scleral spur shortens continuously. Thus, with increasing age the ciliary muscle adopts an anterior-inward position. A similar form is seen in young eyes after ciliary muscle contraction only. There might be a functional relationship between the observed age-changes in the ciliary muscle system and the phenomenon of the so-called 'lens paradox' (steepening of the anterior and posterior curvatures of the disaccommodated lens with age).

Adult↗
PubMed1992

Electrogenic sodium-bicarbonate cotransport in human ciliary muscle cells.

We investigated membrane voltage and intracellular pH (pHi) in cultured human ciliary muscle cells using a cell line (H7CM) and primary-cultured human ciliary muscle cells. 1) Resting potential was 58.9 +/- 1.0 mV in H7CM cells and 61.9 +/- 1.4 mV in primary cultures. The following data are from H7CM cells, but results from primary cultures were basically similar. 2) In HCO3(-)-CO2-buffered solution, removal of extracellular sodium resulted in a depolarization [change in membrane resistance (delta V) = 31.3 +/- 2.8 mV] that was less marked in the absence of HCO3(-)-CO2 (delta V = 0.5 +/- 2.6 mV) and reduced by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) (delta V = 19.3 +/- 1.9 mV). 3) Removal of extracellular HCO3(-)-CO2 led to a depolarization (delta V = 13.2 +/- 0.8 mV) that was abolished in the absence of extracellular sodium and inhibited by DIDS. 4) Intracellular alkalinization led to a depolarization (delta V = 24.7 +/- 2.3 mV), and intracellular acidification resulted in a hyperpolarization (delta V = 9.4 +/- 1.1 mV) that was inhibited by DIDS and dependent on extracellular HCO3(-)-CO2 and sodium. 5) pHi backregulation after an acid load occurred in both the presence and absence of extracellular bicarbonate but not in the absence of extracellular sodium. Our data are consistent with an electrogenic Na(+)-HCO3- cotransport in human ciliary muscle cells, which is activated by intracellular acidification.

Bicarbonates↗
PubMed1992

Synthesis of extracellular matrix components by human ciliary muscle cells in culture.

The production and spatial organization of connective tissue components in ciliary muscle cell cultures was studied with immunohistochemical and ultrastructural methods. Antibodies against collagen types IV and VI, fibronectin and laminin were used. Laminin stains as pericellular network surrounding individual muscle cells. Type IV collagen shows positive cytoplasmic staining and only small foci of extracellular immunofluorescence. Staining for type VI collagen and fibronectin is seen near the ends of the bipolar cells, while the lateral sides of the cells remain unstained. Electronmicroscopy shows that cultured ciliary muscle cells are surrounded by an incomplete basal lamina. In addition, bundles of 5-20 nm thick extracellular microfibrils are seen. The bundles are oriented parallel to the axis of the cells and are in close contact with the cell membrane in areas where membrane-bound dense bands are formed. Immunoelectronmicroscopy indicates that the bundles contain fibronectin and type VI collagen fibrils. While the fibronectin fibrils approach the cell membrane directly, type VI collagen fibrils are usually separated from the cell membrane by fine fibrillous material of different nature. Quality and spatial organization of the extracellular material in ciliary muscle cell cultures shows marked similarities with the extracellular matrix of ciliary muscle in situ.

Adolescent↗
PubMed1991

Different cell populations in bovine trabecular meshwork: an ultrastructural and immunocytochemical study.

Bovine outflow tissue differs markedly from that of humans. Tissue culture studies on the cells of this region are often compared with those of primate trabecular meshwork cells. A thorough cytological and immunocytochemical characterization of the cells of the bovine chamber angle is lacking. We have therefore investigated the cells of the pectinate ligament, the reticular meshwork, the region adjacent to the aqueous plexus, the connective tissue region between reticular meshwork and ciliary muscle and the ciliary muscle itself, ultrastructurally and immunocytochemically with staining for the cytoskeletal proteins vimentin and desmin, for alpha-smooth muscle-actin and rough endoplasmic reticulum (rER). In the pectinate ligament and in the region adjacent to the aqueous plexus, the cells were found to have especially abundant rER and glycogen in their cytoplasm. Vimentin was abundant in the reticular meshwork as positive staining was seen both in frozen and paraffin sections. Alpha-smooth muscle-actin could be found in the region connecting ciliary muscle and reticular meshwork as well as in a small area adjacent to the posterior capillary loops of the aqueous plexus. Ultrastructurally, these cells resembled myofibroblasts. The ciliary muscle cells stained both for vimentin and for alpha-smooth muscle actin.

Actins↗
PubMed1991

Cell cultures of human ciliary muscle: growth, ultrastructural and immunocytochemical characteristics.

Primary ciliary muscle cell cultures derived from human donors (16-91 years) were established and characterized by comparing them with ciliary muscle in tissue sections using immunocytochemical and ultrastructural methods. Monoclonal antibodies against desmin, vimentin, alpha-actinin, smooth muscle (sm) specific alpha-actin and von Willebrand factor were used. In tissue sections of the ciliary body, ciliary muscle cells, vascular muscle cells, pericytes, endothelial cells and fibroblasts stain for vimentin. Both types of muscle cells and the pericytes stain for alpha-sm-actin, but only ciliary muscle cells stain for desmin. For tissue cultures, explants of the meridional and partly the reticular portion of the ciliary muscle were dissected and grown directly or after digestion of the explant with collagenase. Ten primary cell cultures with a typical hill-and-valley growth pattern similar to smooth muscle cells and two with a growth pattern similar to fibroblasts were established. All cultures could be subcultured up to the fifth passage. In fibroblast-like cultures 5-10% of the cells stained for alpha-sm-actin. Staining for desmin was not observed. In smooth muscle-like cultures, all cells stained positive for alpha-sm-actin. Desmin staining was not seen in growing non-confluent smooth muscle-like cultures. In confluent cultures, about 10% of the cells stained positive for desmin, preferentially in areas where the cells had formed hills. No culture stained for von Willebrand factor. Staining for alpha-actinin in smooth muscle-like cultures showed that the dense bands of the myofilaments were arranged in register, similar to the typical ciliary muscle cell morphology seen in tissue sections. Ultrastructurally, the smooth muscle-like cultures showed the typical morphology of cultured smooth muscle cells. We conclude that the smooth muscle-like cultures consist of ciliary muscle cells.

Actinin↗
PubMed1991

Posterior attachment of ciliary muscle in young, accommodating old, presbyopic monkeys.

The authors studied the posterior attachment of the ciliary muscle in seven young (3-10 yr) and five old (26-34 yr) rhesus monkeys by light microscopy and electron microscopy. Posterior attachment of the muscle bundles consisted of elastic tendons, exclusively. The elastic tendons were continuous with the elastic lamina of Bruch's membrane and were also connected by smaller elastic fibers to an elastic meshwork that surrounds the pars plana vessels. In some areas, the tendons formed focal contacts with the endothelial cells. The authors found that in old eyes, the tendons and the elastic fibers of the posterior ciliary body showed pronounced structural changes. The tendons appeared thickened, showed increased amounts of associated microfibrils, and were surrounded by dense layers of thick collagen fibrils. An increased amount of collagen fibrils was also seen between the elastic layer of Bruch's membrane and the pigmented epithelium. A mechanical link between those collagen fibrils and the elastic fibers is suggested by the presence of osmiophilic points of contact. The age-related increase in elastic fibrillar material could cause decreased compliance of the posterior insertion of ciliary muscle and could be an essential factor for presbyopia in rhesus monkeys.

Accommodation, Ocular↗
PubMed1990

Age-related changes of the ciliary muscle in comparison with changes induced by treatment with prostaglandin F2 alpha. An ultrastructural study in rhesus and cynomolgus monkeys.

The relationship between individual ciliary muscle cells and the surrounding connective tissue was studied in the eyes of three normal, young (3-4 years) cynomolgus monkeys (Macaca fascicularis), three aged (34-36 years) rhesus monkeys (Macaca mulatta) and seven young (3-7 years) cynomolgus monkeys topically treated with prostaglandin F2 alpha (PGF2 alpha) for 4-8 days. In normal eyes, collagen fibrils and microfibrils are in places in continuity with the muscle cells' basal lamina, which is connected to the cell membrane by fine fibrillous material. In old eyes, the basal lamina is markedly thickened, masking the connection of fibrils with the muscle cells' membrane. A distinctive finding in several muscle cells of old eyes are electronlucent clefts, 60-80 nm wide, between basal lamina and cell membrane, which are not transversed by fibrils or fibrillous material. The cell membrane of these muscle cells shows large folds filled with disarranged myofilaments. Additionally, these cells contain inclusion bodies consisting of concentrically arranged double membranes. Following treatment with PGF2 alpha, similar changes are seen in young animals, too. Here, the muscle cells have lost their connection to the extracellular fibrils due to a PGF2 alpha-induced lysis of extracellular material. Lack of attachment between basal lamina and altered muscle cells in aged eyes might indicate an involvement of the extracellular matrix in age-related changes of the individual ciliary muscle cells.

Aging↗