Search PubMed⌕ Search

Biomedical subjects

H Jacobsen

Publications and source records attributed to H Jacobsen.

At least 73 records · Page 4Linked to original sources
PubMed1989

[Glucose analysis in general practice. An examination of 4 instruments designed for general practice and self-monitoring].

Several examinations have shown that the analysis of glucose in primary health care is of poor quality. The reason could be the quality of the instruments and/or the way the instruments are operated. We have examined Glucometer II, Glucochek SC, Reflolux II and Hypocount GA. These instruments were studied both in general practice and at Haukeland Hospital. The test results were compared with the routine used in the hospital laboratory. There were no major analytical differences between the instruments. All the instruments were found to have an analytical quality lower than what is recommended by the Norwegian Quality Control. The requested analytical quality for the instrument depends on the clinical needs. We would recommend that these glucose instruments be used to diagnose acute hypo/hyperglucemia and to some extent in control of diabetes. For a certain diagnosis of diabetes, the use of a more precise instrument is to be preferred. The need for a Quality Control program for glucose measurement in primary health care is emphasized.

Blood Glucose↗
PubMed1989

Beta interferon subtype 1 induction by tumor necrosis factor.

Tumor necrosis factor (TNF) induces an antiviral state in various cell lines. This antiviral state is quite similar to that established by interferon (IFN), e.g., TNF treatment of HEp-2 cells induces 2',5'-oligoadenylate synthetase activity. Both antiviral activity and synthetase induction are greatly reduced when TNF treatment occurs in the presence of a beta interferon subtype 1 (IFN-beta 1)-neutralizing antiserum. However, no one has yet directly demonstrated IFN-beta 1 induction, either as an antiviral activity in supernatants from TNF-treated cells or as IFN-specific mRNA by Northern (RNA) blot analysis. We have adopted a recently described in vitro DNA amplification protocol for the detection of specific RNAs. By applying this method to RNA from HEp-2 cells, we could demonstrate increased levels of IFN-beta 1-specific transcripts after TNF treatment. Dose response and kinetics of IFN-beta 1 induction coincided with the TNF-induced antiviral state. Nuclear run-on analysis showed enhanced transcriptional activity of the IFN-beta 1 gene in TNF-treated cells. Our data substantiate a role of IFN-beta 1 as mediator of the biological activity of TNF in HEp-2 cells.

Blotting, Northern↗
PubMed1988

Different antitumor mechanisms of interferon-alpha in the treatment of hairy cell leukemia and renal cell cancer.

There is increasing evidence for the therapeutic effectiveness of Interferon-alpha (IFN-alpha) in malignant diseases. However, the antitumor mechanisms of IFN-alpha are not known. Using two examples, hairy Cell leukemia (HCL) and renal cell cancer (RCC), it is shown that the requirements for successful IFN-alpha therapy of HCL and RCC are different. In HCL low doses of IFN-alpha are sufficient to treat the disease. The reduction of hairy cells in peripheral blood is detectable within the first week of treatment. The endogenous IFN-alpha production in these patients is impaired as demonstrated by the lack of IFN-alpha induction and by low levels of 2-5 oligoadenylate synthetase in peripheral blood mononuclear cells. A possible reason for deficient endogenous IFN-alpha production is the lack of monocytes in HCL patients. It is likely that therapy with low doses of IFN-alpha substitutes for the endogenous IFN-alpha deficiency. In RCC comparatively high doses of IFN-alpha are necessary for a clinical response. There may be differences between the effectiveness of natural and recombinant alpha interferons. High doses given within a week seem to be more important than high single doses, which therefore suggests the need of daily treatment. Responses of RCC to IFN-alpha therapy are usually seen several months after the beginning of therapy. These differences in the effectiveness of IFN-alpha therapy for HCL and RCC suggest that IFN-alpha acts differently in the treatment of each disease.

2',5'-Oligoadenylate Synthetase↗
PubMed1988

Interferon treatment inhibits onset of herpes simplex virus immediate-early transcription.

Pretreatment of primary cultures of splenic mouse macrophages with murine IFN-alpha/beta leads to a stable inhibition of herpes simplex virus type 1. Analysis of viral DNA, RNA, and protein synthesis identifies expression of "immediate-early" genes as a major target of IFN-mediated inhibition. Determination of viral DNA in the nuclei early after infection, i.e., before onset of DNA replication, suggests that virus uptake, transport to the nucleus, and DNA stability are not decreased in IFN-pretreated macrophages. Nuclear runoff transcription analysis shows a significant reduction of immediate-early transcription rates following IFN treatment. End-specific probes for the ICP4 gene locate the inhibition to the onset of transcription. Northern blot analysis reveals a decrease in ICP4 transcripts in accordance with the observed inhibition of transcription. The observed inhibition of early gene transcription may be a consequence of decreased immediate-early gene expression.

Animals↗
PubMed1988

Antiviral activity of tumour necrosis factor. Synergism with interferons and induction of oligo-2',5'-adenylate synthetase.

Tumour necrosis factor (TNF) induces antiviral activity in HEp-2 cells. Virus yield reduction assays with vesicular stomatitis virus as challenging virus demonstrated that the antiviral state was more pronounced in confluent cultures under low serum conditions. A significant enhancement of the antiviral state was obtained by combining TNF with low concentrations of either interferon (IFN)-beta 1 or IFN-gamma. The reduction in virus yield was significantly higher than that expected from summation of the independent antiviral activities of either substance alone, i.e. TNF and IFN acted synergistically as antiviral agents. Synergism of TNF with IFN-beta or IFN-gamma appeared to be mediated by different pathways, since different requirements for pretreatment and different effects on oligo-2',5'-adenylate synthetase (2-5AS) induction were observed. Induction of 2-5AS by TNF could be shown to be an indirect event that was sensitive to an antiserum against natural IFN-beta 1.

2',5'-Oligoadenylate Synthetase↗
PubMed1988

Evaluation of serum separator tubes as a mail transport device in primary health care.

Serum separator tubes were evaluated as a serum separator system and a mail transport device. Using conventional tubes as controls, 26 serum constituents were examined. The samples were mailed from three different general practitioners to a central laboratory. Thirteen constituents had concentrations that were significantly different from the concentration in the conventional tubes. When medically important coefficients of variations were taken into account, however, the changes of only two constituents (potassium and cobalamin) were regarded as important.

Blood Chemical Analysis↗
PubMed1987

Selection and characterization of interferon-sensitive cells derived from an interferon-resistant NIH 3T3 line.

We have developed a selection protocol to isolate interferon (IFN)-sensitive subclones directly from an IFN-resistant cell population. The protocol uses encephalomyocarditis virus (EMCV) as a selection agent in combination with pretreatment with low doses of IFN and subsequent growth in the presence of virus-neutralizing antiserum. We have applied this protocol to the partially IFN-resistant NIH 3T3 clone 1 line and have obtained a number of IFN-sensitive subclones. Sensitivity to IFN was restricted to protection against EMCV. Replication of vesicular stomatitis virus as well as cell growth were resistant to IFN treatment as in the original clone 1 line. We have compared levels of 2',5'-oligoadenylate (2-5A) synthetase, dsRNA-activated protein kinase and 2-5A-dependent RNase in some IFN-sensitive subclones and found no difference from the resistant clone 1 cells. Markedly decreased levels of 2-5A-dependent RNase and thus a defective 2-5A pathway have been implicated as a possible cause for the partial resistance of clone 1 cells to IFN. Since the selected IFN-sensitive subclones are of the same phenotype in this respect as the clone 1 line we suggest that inhibition of EMCV in these lines occurs through a mechanism independent of the 2-5A system.

2',5'-Oligoadenylate Synthetase↗
PubMed1986

Synthesis of herpes simplex virus proteins and nucleic acids in interferon-treated macrophages.

Mouse macrophages grown from spleen cells were found to be very sensitive to the interferon (IFN) activity against herpes simplex virus type 1 (HSV-1). Therefore we have used these cells to investigate the level at which IFN blocks the replication of HSV-1. IFN treatment resulted in a strong inhibition of the induction of HSV DNA polymerase and other beta proteins. RNA hybridization experiments revealed that the amount of mRNA for the beta protein thymidine kinase was strongly reduced in IFN treated HSV-1 infected cells. Analysis of the effect of IFN on expression of the alpha genes indicated a strong inhibition of alpha protein synthesis. In contrast the synthesis of mRNA of the alpha protein ICP 4 was only moderately inhibited. The results indicate that IFN primarily acts on the translation of HSV alpha proteins.

Animals↗
PubMed1986

Stability of haematological constituents during simulated mail transport as measured by Coulter Counter S plus II or Technicon H 6000.

Stability of blood constituents after mail transport was examined using two different automated haematology instruments, that is, Coulter Counter S plus II and Technicon H 6000. The results were analysed by two different statistical methods. In all but four cases these methods yielded similar results. The B-LPC, B-EPC B-Hb, B-EVF, E-MCH, E-MCHC and B-TPC were stable after mail transport for 48 h when measured with Coulter Counter S plus II. In contrast, none of these parameters were stable when measured with Technicon H 6000. The differential count measured by cytochemical staining technique with Technicon H 6000 was stable for 72 h whereas the percentage of L-Lymphocytes measured with Coulter Counter S plus II was unstable after 24 h of mail transport. The criteria of stability are discussed in relation to changes of constituents that are of importance in medical decision making.

Autoanalysis↗
PubMed1986

Interferons and antiviral activity.

Interferons are endogenous antiviral agents which mediate the early defense of the organism against virus infection. The target of interferons is the cell rather than the virus itself. Through binding to specific receptors on the cell surface and subsequent activation of specific genes interferons induce an antiviral state which makes cells less permissive for virus replication. The antiviral state is composed of various antiviral mechanisms which seem to act independently and show some specificity for different viruses. Translational control affecting viral protein synthesis may be the most common mechanism through which virus is inhibited. There is evidence that antiviral and antigrowth activities of interferons share similar mechanisms.

2',5'-Oligoadenylate Synthetase↗
PubMed1985

Antibody-nucleic acid interactions. Monoclonal antibodies define different antigenic domains in 2',5'-oligoadenylates.

To define the epitopes involved in binding anti-oligonucleotide antibodies, several hybridomas producing monoclonal antibodies directed against 2',5'-oligoadenylate were established. A solid-phase enzyme-linked immunoassay that employed microtiter wells coated with Ficoll-2',5'-oligoadenylate conjugates proved useful in screening and characterizing hybridoma supernatants. Control experiments demonstrated that the conjugates were irreversibly adsorbed to polystyrene wells under the conditions employed in the assay. Reactivity of monoclonal antibodies with numerous analogues of 2',5'-oligoadenylate was measured by using a competition assay. Several monoclonal antibodies originating from different mice immunized with the same or different immunogens possessed distinctive fine specificities. At least one 2',5'-phosphodiester bond was important in forming each epitope, suggesting that the ribose phosphate backbone is a critical element in defining an antigenic domain of an oligonucleotide. The purine bases were also important, and modification of the bases had varied effects on the extent of antibody recognition. The length of the oligonucleotide and the nature of the termini were also of some importance. In several instances the modification created by linkage of 2',5'-oligoadenylate to carrier protein also contributed to the determinant. The monoclonal antibody most specific for 2',5'-oligoadenylates was relatively insensitive to ionic strength. In contrast, a monoclonal antibody with a 2',5'-oligopurine specificity appeared to bind 2',5'-oligoadenylate through one ion pair, whereas the binding of a monoclonal antibody with a low degree of base specificity appeared to bind through two ion pairs. The results demonstrated that 2',5'-linked oligoadenylate-protein complexes possess at least three distinct oligonucleotide-related antigenic surfaces that can be recognized with high apparent affinity by monoclonal antibodies. A model for the three epitopes is presented.

Adenine Nucleotides↗
PubMed1985

Regulation of ppp(A2'p)nA-dependent RNase levels during interferon treatment and cell differentiation.

The intracellular effector oligonucleotides ppp(A2'p)nA (n = 2- greater than or equal to 4) regulate the breakdown of RNA by activating ppp(A2'p)nA-dependent RNase. Cellular levels of this RNase were demonstrated to be regulated during differentiation of murine embryonal carcinoma cells. An induction of this RNase by interferon was demonstrated in each of three differentiated cell types (F9 clone 9, PYS, and PSA 5E) by analyzing rRNA breakdown following the introduction of ppp(A2'p)nA into the intact cells. In contrast, in three undifferentiated embryonal carcinoma cell lines (F9, PC13 clone 5, and Nulli 2A) there was little if any ppp(A2'p)nA-dependent RNase either with or without interferon pretreatment. These results were confirmed by affinity labeling of the RNase in cell-free systems. Addition of the proteinase inhibitor, leupeptin, to the cell lysis buffer was necessary to stabilize the RNase against cleavage to discrete breakdown products. Moreover, during differentiation of PC13 clone 5 cells by retinoic acid and N6,O2'-dibutyryl-adenosine 3',5'-monophosphate there was a gradual induction of ppp(A2'p)nA-dependent RNase. The expression of this RNase is, therefore, greatly enhanced during cell differentiation. In addition, the double-stranded-RNA-dependent protein kinase was investigated and was found to be interferon-inducible in all of the cell lines regardless of the state of cell differentiation.

Affinity Labels↗
PubMed1985

Inhibition of replication of herpes simplex virus in mouse macrophages by interferons.

The replication of herpes simplex virus (HSV) type 1 in macrophages grown from spleen cells of mouse strains susceptible to HSV infection in vivo was very sensitive to interferon (IFN). Different types of mouse IFN (alpha, beta, gamma) exhibited similar antiviral activities. However, treatment of cells with IFN-gamma in combination with IFN-alpha or IFN-beta resulted in a synergistic inhibition of virus growth. As shown by assaying HSV DNA polymerase, IFN inhibited expression of the beta-genes. Inhibition of enzyme induction correlated well with the reduction of viral yield. Induction of HSV DNA polymerase was delayed by IFN in a dose-dependent manner. These results show that IFN inhibits HSV replication at an early step prior to or during the synthesis of beta-proteins.

Animals↗
PubMed1985

Antiviral activity of prostaglandin A on encephalomyocarditis virus-infected cells: a unique effect unrelated to interferon.

Antiviral effects of prostaglandins of the A series (PGAs) on Sendai, vaccinia and vesicular stomatitis viruses have previously been reported and a relationship between the antiviral actions of PGAs and interferons has been suggested. We have investigated the antiviral activity of PGAs on encephalomyocarditis (EMC) virus. Using single-cycle assays of virus replication our results indicate that PGAs only inhibit when present in the culture medium after the cells are infected, and that they are most effective during incubation periods including from 3 to 5 h post-infection. Furthermore, viral RNA synthesis is blocked in infected cells treated with PGA and, as a result, viral antigens are greatly reduced in the cytoplasm of the cells 5 h post-infection. Since the antiviral effect of PGAs is unperturbed by actinomycin D, when cellular RNA synthesis is greatly reduced, it appears unlikely that induction of new cellular proteins is the reason for the antiviral activity of PGAs. In separate experiments we were unable to demonstrate directly the induction of interferon, or of the two dsRNA-dependent enzymes, 2',5'-oligoadenylate synthetase and protein kinase, which are greatly increased in interferon-treated cells. Thus, we conclude that the antiviral activity of PGAs is unrelated to the antiviral action of interferons and involves a unique mechanism independent of cellular protein synthesis.

2',5'-Oligoadenylate Synthetase↗
PubMed1985

Multiple intercostal blocks by a single injection? A clinical and radiological investigation.

Three different techniques for producing multiple intercostal nerve blocks using bupivacaine were compared in volunteers. The techniques used were multiple injections at intercostal nerves 7-11, or a single injection employing a needle or a catheter inserted in the 9th intercostal space. The injections were made at the costal angle. The anatomical spread of a mixture of a local anaesthetic and a radio-opaque fluid following the single injection technique at the ninth intercostal space or at the subcostal space was evaluated by computerized x-ray tomography (CT). The distribution of cutaneous analgesia/hypalgesia following all techniques was evaluated by pin prick. No spread of the local anaesthetic to adjacent intercostal spaces or to the paravertebral space could be shown by CT. The distribution of cutaneous analgesia was limited to three segments or less following a single injection. No difference in blood levels of bupivacaine could be found. It is concluded that the single injection technique of producing multiple intercostal nerve blocks is inferior to the multiple injection technique.

Adult↗
PubMed1985

Plasma exchange in myasthenia gravis: clinical effect.

Seventeen patients suffering from myasthenia gravis were treated with plasma exchange. Serious complications were not encountered. The effect usually appeared on the second or the third day of treatment. In 12 patients with a total of 31 plasma exchange courses, the treatment resulted in a shift in Osserman group. Six of these had long-standing remissions. Three patients responded moderately and two patients did not respond to plasma exchange.

Adult↗
PubMed1985

Testicular and glandular contributions to the prolactin pool in human semen.

The immunoreactive prolactin in human seminal plasma originates predominantly from two sources, the seminal vesicles and the testicular-epididymal axis. The following evidence supported a testicular-epididymal origin: Vasectomy reduced the content of prolactin in the ejaculates by 50%; the concentration of seminal prolactin was highly correlated (r = 0.54, p less than 0.003) with the concentration of sperm in a normal population of young and middle-aged men; and prolactin concentrations in the split ejaculates of normospermic men revealed a profile that corresponded to the sperm distribution pattern. Evidence supporting an additional contribution from the seminal vesicles included the following. The split ejaculate of an azoospermic individual coincided more with the distribution of the vesicular parameter fructose; vasectomy did not cause the disappearance of prolactin from the ejaculate; and split-ejaculate analyses weakened the possibility of a major prostatic source.

Acid Phosphatase↗