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Biomedical subjects

J Christensen

Publications and source records attributed to J Christensen.

At least 127 records · Page 7Linked to original sources
PubMed1994

Local intra-arterial thrombolysis with urokinase combined with balloon angioplasty in the lower extremities.

OBJECTIVE: To assess the effect of thrombolysis with urokinase in the treatment of acute and subacute arterial thrombosis or graft occlusion. DESIGN: Open study. SETTING: County hospital, Sweden. SUBJECTS: 20 selected patients with lower limb arterial or graft occlusions of less than six months' duration, 17 of whom presented with rest pain (four with ulceration) and the rest with claudication. INTERVENTIONS: High dose urokinase (4,000 IU/minute for up to 8 hours) given intra-arterially, followed by oral anticoagulation for 6 months. MAIN OUTCOME MEASURES: Patency at one month and one year, morbidity and mortality. RESULTS: At one month 6/17 who presented with rest pain could walk unlimited distances, 8 had claudication between 50 and 500 m, and 3 had no improvement; 2 had had below knee amputations. At one year only 4 could walk unlimited distances, 5 had claudication between 50 and 500 m, 2 had rest pain, 4 had had major amputations, and 1 was dead and 1 was lost to follow up. Five patients had had 10 additional procedures. Of the 3 who presented with claudication, 2 improved their walking distance to at least 100 m, and one had total relief of symptoms after one month; after a year one had no symptoms, one had mild claudication, and one had severe claudication (120 m). Three developed complications: one bleeding 12 hours after treatment was successfully treated by transfusion, one embolism to the midpopliteal artery was successfully treated by embolectomy, and one episode of bleeding during lysis ceased when treatment was stopped. CONCLUSION: Thrombolysis is at best only an adjunct to balloon angioplasty or traditional vascular operations.

Acute Disease↗
PubMed1993

Identification of oxidation products of 5-aminosalicylic acid in faeces and the study of their formation in vitro.

The formation of three oxidant-derived products of 5-aminosalicylic acid (5-ASA) in vivo was demonstrated in patients with active ulcerative colitis as well as in healthy subjects. The products were isolated from faeces by preparative HPLC and their chemical structures were found to be oxidation products of 5-ASA using 1H-NMR spectroscopy and mass spectrometry. Reactions carried out in vitro between 5-ASA and oxidants suggested to be present in the inflamed bowel verified that the hypochlorite-mediated oxidation of 5-ASA as well as the haemoglobin-catalysed H2O2-dependent oxidation of 5-ASA resulted in the formation of a single oxidation product of 5-ASA. This product was similar to, but not identical to any of the products identified in faeces from patients receiving 5-ASA. Oxygen radical-mediated oxidation of 5-ASA gave several products, different from the products isolated. Finally, it was verified that the products formed in vivo are not formed as a result of autooxidation of 5-ASA either in faeces extract or in pharmaceuticals.

Aminosalicylic Acids↗
PubMed1993

Biomechanical characteristics of the human esophagus.

Biomechanical wall properties of the human esophagus were studied. A probe, with a balloon designed for simultaneous measurement of cross-sectional area and intraluminal pressure, was placed in the esophagus 30 cm from the incisors. Tone was not detected before inflation of the balloon. When the balloon was inflated stepwise with pressures up to 40 cm H2O (30.7 mmHg), measurement of cross-sectional area allowed calculation of distensibility and circumferential wall tension. Balloon cross-sectional area increased linearly with increased balloon pressure. Balloon distension induced contractions, both proximal to the balloon and at the site of distension, at a balloon pressure of about 15 cm H2O (11.5 mm Hg). The cross-sectional area for the threshold for distension induced contractions was 153 +/- 12 mm2 (diameter 14 mm). At the onset of these contractions, the contraction force was 15-20 cm H2O (11.5-15.3 mm Hg) and it increased to 47-58 cm H2O (36.1-44 mm Hg) at a balloon pressure of 20-40 cm H2O (15.3-30.7 mm Hg). Circumferential wall tension increased with increasing intraluminal pressure in an almost exponential manner. The pressure elastic modulus increased steeply at lower balloon pressures (10-20 cm H2O) (7.7-11.5 mm Hg), but at higher balloon pressures (20-40 cm H2O) (15.3-30.7 mm Hg) this increase was less. The circumferential wall tension and wall stiffness of the human esophagus increased with increasing balloon pressure and cross-sectional area. When a threshold is reached, distension induced contractions both proximal and distal to the balloon and at the distension site.

Adult↗
PubMed1993

Oral health and treatment needs among patients in psychiatric institutions for the elderly.

The purpose of the study was to assess oral health and treatment needs among elderly in psychiatric institutions in a Danish county. The study serves as baseline for the evaluation of a newly established oral health care program in the county. The study population comprised the residents in eight institutions (n = 407). Two thirds of the residents were edentulous, 34% of the dentate had one or more root remnants, and 55% had untreated decay. The dentate with regular dental visiting habits had significantly less untreated decay than the irregular users. The oral hygiene was poor, but was not related to whether or not the elderly were assisted in daily oral hygiene. The evaluation of the program will show to what extent treatment takes place, and whether or not oral hygiene improves.

Adult↗
PubMed1993

Expression of Aleutian mink disease parvovirus proteins in a baculovirus vector system.

We have previously published a detailed transcription map of Aleutian mink disease parvovirus (ADV) and proposed a model for the translation of the two virion structural proteins (VP1 and VP2) and three nonstructural proteins (NS-1, NS-2, and NS-3) (S. Alexandersen, M. E. Bloom, and S. Perryman, J. Virol. 62:3684-3994, 1988). To verify and further characterize this model, we cloned the predicted open reading frames for NS-1, NS-2, NS-3, VP1-VP2, and VP2 alone into a recombinant baculovirus and expressed them in Sf9 insect cells. Expression of VP1-VP2 or VP2 alone in cDNA and in the genomic form was achieved. The expressed proteins had molecular weights similar to those of the corresponding proteins of wild-type ADV-G, although the ratio of VP1 to VP2 was altered. The recombinant baculovirus-expressed ADV VP1 and VP2 showed nuclear localization in Sf9 cells and were able to form particles indistinguishable, by electron microscopy, from wild-type virus. The large nonstructural protein, NS-1, showed predominantly nuclear localization in Sf9 cells when analyzed by immunofluorescence and had a molecular weight similar to that of wild-type ADV NS-1. Moreover, expression of NS-1 in Sf9 cells caused a change in morphology of the cells and resulted in 10-times-lower titers of recombinant baculovirus during infection, suggesting a cytostatic or cytotoxic action of this protein. The smaller NS-2 gene product seems to be located in the cytoplasm. When analyzed by Western immunoblotting, NS-2 comigrated with an approximately 16-kDa band seen in lysates of ADV-infected feline kidney cells. The putative NS-3 gene product exhibited a diffuse distribution in Sf9 cells and had a molecular weight of approximately 10,000. All of the expressed ADV-encoded proteins were recognized by sera from ADV-infected mink. Thus, expression of ADV cDNAs allowed assignment of the different mRNAs to the viral proteins observed during ADV infection in cell culture and supported our previously proposed ADV transcriptional and translational scheme. Moreover, the production of structural proteins from a full-length NS-2 mRNA may add to the repertoire of parvovirus gene expression.

Aleutian Mink Disease Virus↗
PubMed1993

Identification of alternatively spliced mRNAs encoding potential new regulatory proteins in cattle infected with bovine leukemia virus.

The polymerase chain reaction was used to detect and characterize low-abundance bovine leukemia virus (BLV) mRNAs. In infected cattle we could detect spliced mRNA with a splice pattern consistent with a Tax/Rex mRNA, as well as at least four alternatively spliced RNAs. Two of the alternatively spliced mRNAs encoded hitherto unrecognized BLV proteins, designated RIII and GIV. The Tax/Rex and alternatively spliced mRNAs could be detected at their highest levels in BLV-infected cell cultures; the next highest levels were found in samples from calves experimentally infected at 6 weeks postinoculation. Alternatively spliced mRNAs were also expressed, albeit at lower levels, in naturally infected animals; they were detected by a nested polymerase chain reaction. Interestingly, the GIV mRNA was specifically detected in naturally infected cows with persistent lymphocytosis and in two of five calves at 6 months after experimental infection with BLV. Furthermore, the calf with the strongest signal for GIV had the highest lymphocyte counts. These data may suggest a correlation between expression of the GIV product and development of persistent lymphocytosis. Some of the donor and acceptor sites in the alternatively spliced mRNAs were highly unusual. The biological mechanisms and significance of such a choice of unexpected splice sites are currently unknown.

Alternative Splicing↗
PubMed1993

Comparison of promoter activity in Aleutian mink disease parvovirus, minute virus of mice, and canine parvovirus: possible role of weak promoters in the pathogenesis of Aleutian mink disease parvovirus infection.

Aleutian mink disease parvovirus (ADV) infection causes both acute and chronic disease in mink, and we have previously shown that it is the level of viral gene expression that determines the disease pattern. To study the gene regulation of ADV, we have cloned the P3 ADV and P36 ADV promoters in front of a reporter gene, the chloramphenicol acetyltransferase (CAT) gene, and analyzed these constructs by transient transfection in a feline kidney cell line and mouse NIH 3T3 cells. The genes for ADV structural proteins (VP1 and VP2) and the nonstructural proteins (NS-1, NS-2, and NS-3) were cloned into a eukaryotic expression vector, and their functions in regulation of the P3 ADV and P36 ADV promoters were examined in cotransfection experiments. The ADV NS-1 protein was able to transactivate the P36 ADV promoter and, to a lesser degree, the P3 ADV promoter. Constitutive activities of the P3 ADV and P36 ADV promoters were weaker than those of the corresponding promoters from the prototypic parvovirus minute virus of mice (MVM) and canine parvovirus (CPV). Also, the level of transactivation of the P36 ADV promoter was much lower than those of the corresponding P38 MVM and P38 CPV promoters transactivated with MVM NS-1. Moreover, the ADV NS-1 gene product could transactivate the P38 MVM promoter to higher levels than it could transactivate the P36 ADV promoter, while the P36 ADV promoter could be transactivated by MVM NS-1 and ADV NS-1 to similar levels. Taken together, these data indicated that cis-acting sequences in the P36 ADV promoter play a major role in determining the low level of transactivation observed. The P3 ADV and P4 MVM promoters could be transactivated to some degree by their respective NS-1 gene products. However, in contrast to the situation for the late promoters, switching NS-1 proteins between the two viruses was not possible. This finding may indicate a different mechanism of transactivation of the early promoters (P3 ADV and P4 MVM) compared with the late (P36 ADV and P38 MVM) promoters. In summary, the constitutive levels of expression from the ADV promoters are weaker than the levels from the corresponding promoters of MVM and CPV. Moreover, the level of NS-1-mediated transactivation of the late ADV promoter is impaired compared with the level of transactivation of the late promoters of MVM and CPV.(ABSTRACT TRUNCATED AT 400 WORDS)

3T3 Cells↗
PubMed1993

cis-acting sequences in the Aleutian mink disease parvovirus late promoter important for transcription: comparison to the canine parvovirus and minute virus of mice.

We are currently investigating the regulation of transcription of the Aleutian mink disease parvovirus (ADV). ADV causes a chronic immune complex-mediated condition known as classical Aleutian disease, characterized by slow viral replication. This slow replication is an intrinsic property of ADV and distinguishes it from the more prototypic parvoviruses such as minute virus of mice (MVM) and canine parvovirus (CPV). We have previously suggested a role for the weak ADV promoters in the slow replication and thereby the absence of acute cytopathology and instead establishment of persistent ADV infection with progressive immune complex-mediated chronic lesions. In this study, we have mapped the cis-acting sequences around the ADV P36 promoter responsible for both constitutive transcription and transactivation mediated by the nonstructural protein 1. The mapping was performed by using endpoint deletions of the ADV P36 promoter and by making chimeras between the ADV P36 and MVM P38 promoters. We found the weak constitutive activity of the ADV P36 promoter to be caused by suboptimal promoter proximal sequences, while the low level of transactivation was caused mainly by an upstream region including sequences with homology to the transactivation responsive element (tar) of the H-1 parvovirus (M.-L. Gu, F.-X. Chen, and S. L. Rhode, Virology 187:10-17, 1992). We also found the corresponding regions in the MVM and CPV P38 promoters to be important for transactivation of these promoters by making 5' deletions of the promoter region. In addition, it was found that MVM tar-like and upstream sequences could transfer high nonstructural protein 1 responsiveness to the ADV promoter even though the distance between the tar-like element and the TATA box was significantly changed. On the basis of comparative data for ADV, MVM, CPV, and H-1, a new clustered motif (TTGGTT) is proposed to be the responsive cis-acting element for transactivation. Homology comparison of the specific transcriptional elements of the ADV P36, MVM P38, and CPV P38 promoters suggests that few, but crucial, changes in the ADV P36 promoter and upstream region are responsible for the weak constitutive activity and low level of transactivation of the ADV P36 promoter.

Aleutian Mink Disease↗
PubMed1993

Recurrent angioedema and urticaria.

The case reported here illustrates the life-threatening aspects of angioedema and the need to thoroughly investigate the possible causes of this clinical finding. As discussed, the causes of angioedema are numerous. Commonly implicated in drug-induced angioedema are antihypertensive ACE inhibitor drugs, as was originally thought with this patient. Because of her skin lesions and macrocytic anemia, further studies were done. These studies led to a diagnosis of hypocomplementemic urticarial vasculitis syndrome, an uncommon to rare form of acquired angioedema, urticarial vasculitis, arthritis, and obstructive airway disease associated with the production of autoantibodies to C1q. It is an autoimmune disorder related to but separate from SLE.

Angioedema↗
PubMed1993

Clozapine shows promise in schizophrenia treatment.

Clozapine represents the first significant advance in the pharmacotherapy of schizophrenia since development of phenothiazine antipsychotic drugs in the 1950s and 60s, yet only about 10% of potential patients nationwide are taking the medication.

Clozapine↗
PubMed1992

How can a standard software package for data management in anesthesia be achieved?

Collecting data for administrative, statistical, medical, and organizational purposes is becoming increasingly important in anesthesia. In 1986 the Swiss Society for Anesthesiology decided to create a program that would be compatible for different computers and would expedite data collection. The system developed was called Information System for Operations (ISOP), which was written in the database and programming system Massachusetts General Hospital Utility Multi Programming System (MUMPS). It was installed in eight hospitals and met the initial requirements, but the individual requirements of the hospitals were greatly underestimated. MUMPS has an impressive data storage capability and handling when used in a personal computer (PC) network. The user-interface, however, is inferior to other PC packages, partly because windowing and mouse support were not implemented when the ANSI standard was set. Improved statistical programs, a module for on-line data acquisition, and intensive care unit (ICU) use will be additional modules to the program.

Anesthesia Department, Hospital↗
PubMed1992

Distributions of interstitial cells of Cajal in stomach and colon of cat, dog, ferret, opossum, rat, guinea pig and rabbit.

Electrical slow waves vary in prominence from one location to another in stomach and colon. If interstitial cells of Cajal are involved in generation of the slow waves, they might be more abundant in regions where slow waves are prominent than in regions where slow waves are small or absent. We calculated the density of distribution of interstitial cells of Cajal in colon and stomach of cat, dog, ferret, guinea pig, opossum, rabbit, and rat, using the zinc iodide-osmic acid reaction for light microscopy. The cells in the stomach were concentrated in the myenteric plexus and in the circular muscle layer. Along the greater curvature, cells were relatively sparse in the fundus, more frequent in the corpus and densest in the antrum. Along the lesser curvature, they were denser distally than proximally in all species except guinea pig. In the colon most cells lay with an axonal network at the circular muscle-submucosal interface. The axons were sparse in the cecum but uniformly conspicuous from the ileocolonic junction to the internal and sphincter. The density of the interstitial cells of Cajal in cat, dog, opossum, and rabbit rose from a relatively low level in the cecum to a maximum in the mid-colon, declining toward the rectum. In guinea pig, rat, and ferret, the levels throughout the most proximal colon were high. Since gastric slow waves are absent from the fundus, diminutive in the body, and prominent in the antrum, the density of interstitial cells of Cajal in the stomach roughly parallels the prominence of slow waves. Colonic slow waves are most prominent in the right colon and mid-colon, and so the density distribution of interstitial cells of Cajal in the colon also roughly parallels the prominence of slow waves.

Animals↗
PubMed1992

Biomechanical properties of duodenal wall and duodenal tone during phase I and phase II of the MMC.

We used a new method, impedance planimetry, to look at variations in compliance, tone, and distension-induced peristaltic activity during phase I and phase II of the migrating myoelectric complex (MMC) in the human duodenum. A balloon was inflated stepwise with pressures up to 30 cmH2O in the duodenum, while the pressure and balloon cross-sectional area (CSA) were measured simultaneously. The biomechanical wall parameters were calculated from these measurements. Nine duodenal phase IIIs were recorded in six subjects. A balloon pressure of 20 cmH2O induced a smaller CSA in early phase I [266 (236-324) mm2] than in late phase II [385 (276-474) mm2] (P < 0.05). Balloon distensions elicited no contractions in phase I, whereas they increased contractile activity 60% (P < 0.05) proximal to the balloon and 4% distal to the balloon in late phase II. Step distensions in phase I with balloon pressures between 10 and 30 cmH2O increased the CSA from 40 (30-81) to 645 (603-704) mm2. It increased circumferential wall tension from 35 (28-63) to 429 (402-466) mm x cmH2O and the pressure elastic modulus from 9.7 (9.0-14.7) to 33.8 (27.6-33.8) cmH2O, respectively. Thus compliance differs from phase I to phase II. This is most likely caused by increased smooth muscle tone during phase I. Duodenal wall stiffness increases with the balloon pressure applied.

Adult↗