Search PubMed⌕ Search

Biomedical subjects

S Jacobsson

Publications and source records attributed to S Jacobsson.

At least 19 recordsLinked to original sources
PubMed2000

Optimization of capillary electrophoresis conditions for coupling to a mass spectrometer via a sheathless interface.

When optimizing a capillary electrophoresis/electrospray ionization mass spectrometry (CE/ESI-MS) system, consideration has to be given not only to the separation but also to the electrospray stability. Methods developed for CE/UV analysis of drugs and peptides were considered and modified to be suitable for a CE/MS system with a robust sheathless interface. Different concentrations of the organic modifiers acetonitrile, methanol and 2-propanol were used in the separation buffer. The type and concentrations of these modifiers were also compared with reference to electrospray stability, sensitivity and time of analysis. In addition, different ionic strengths in the buffers were evaluated with reference to electrospray stability. The repeatability was used for the estimation of electrospray stability. The degree to which these parameters influenced the separation and the ESI stability was studied using a nine-peptide standard mixture and the antibiotic drugs bacampicillin and ampicillin as test substances. The analysis time and resolution were used as measures of the efficiency of the separation. A time-of-flight MS analyzer was used since it has the potential advantages of becoming a better fit for integration of CE with MS owing to the speed and sensitivity of this mass analyzer. The detection limit, i.e. 1 microM, for bacampicillin was comparable to what could be achieved with CE/MS on a quadrupole instrument using selected ion monitoring and sheath flow ESI.

Electrophoresis, Capillary↗
PubMed2000

Current awareness.

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of mass spectrometry. Each bibliography is divided into 11 sections: 1 Books, Reviews & Symposia; 2 Instrumental Techniques & Methods; 3 Gas Phase Ion Chemistry; 4 Biology/Biochemistry: Amino Acids, Peptides & Proteins; Carbohydrates; Lipids; Nucleic Acids; 5 Pharmacology/Toxicology; 6 Natural Products; 7 Analysis of Organic Compounds; 8 Analysis of Inorganics/Organometallics; 9 Surface Analysis; 10 Environmental Analysis; 11 Elemental Analysis. Within each section, articles are listed in alphabetical order with respect to author (5 Weeks journals - Search completed at 27th. Apr 2000)

Bibliographies as Topic↗
PubMed2000

A transforming growth factor-beta1-mediated bystander immune suppression could be associated with remission of chronic idiopathic thrombocytopenic purpura.

Bystander immune suppression has been demonstrated in experimental models of oral immune tolerance induction. This phenomenon is associated with expression of transforming growth factor (TGF)-beta1 and T-helper cell (Th) 2 cytokines. We have studied serum levels of Th cytokines and B- and T-lymphocyte subsets in chronic idiopathic thrombocytopenic purpura (ITP), a disorder in which the production of platelet autoantibodies might be caused by a cytokine network dysregulation. Forty-six patients with ITP were separated into three groups depending on the platelet count (pltc): (1) < 50 x 10(9)/l, (2) 50-150 x 10(9)/l and (3) > 150 x 10(9)/l. We found significantly elevated plasma levels of the Th3 cytokine TGF-beta1 in patients with pltc >150x10(9)/l (23.5+/-2.8ng/ml), compared with patients with pltc <50x10(9)/l (2.3+/-0.6 ng/ml; P<0.0001), patients with pltc 50-150x 10(9)/l (7.2+/-1.7 ng/ml; P<0.0001) and healthy volunteers (9.8+/-1.3 ng/ml; P<0.01). The serum levels of the Thl cytokines interleukin (IL)-2 and interferon (IFN)-y were below the detection limits of the assays. Likewise, the Th2 cytokine IL-4 was not detectable or was very low both in patients and controls. The serum levels of IL-10, a Th2 cytokine, were within the assay range and patients with pltc <50 x 10(9)/l had significantly lower levels (0.6+/-0.1 pg/ml) than both patients with pltc 50-150 x 10(9)/l (1.8 +/- 0.1 pg/ml; P<0.005) and healthy volunteers (1.4+/-0.1 pg/ml; P<0.005). Furthermore, patients with pltc <50 x 10(9)/l and splenectomised patients had significantly higher levels of CD4 + CD25 + activated T cells [26.2 +/- 14.8% (P<0.05) and 26.7+/-11.9% (P<0.005), respectively] than healthy controls (16.5+/-4.0%). Also, the number of natural killer (NK) cells among patients with pltc >150 x 10(9)/l were significantly elevated (26.6+/-16.0%; P<0.05) compared with controls (17.4+/-7.6%). In conclusion, our data corroborate previous findings of elevated numbers of activated T cells in chronic ITP patients with active disease, but neither a clear-cut Th1 nor a Th2 serum cytokine profile could be established. However, ITP in remission was associated with elevated TGF-beta1, which might be a part of a bystander immune suppression. We propose that the effect of possible expression of TGF-beta1 by oral immune tolerance induction deserves to be explored in ITP patients with an active disease.

Adolescent↗
PubMed2000

A tomographic method for experimental verification of the integrity of spent nuclear fuel

A tomographic method for verification of the integrity of spent nuclear fuel assemblies has been developed. The gamma radiation field emanating from emitted radiation from within the assembly is recorded and utilised for reconstructing the internal source distribution. Simulations of an experimental procedure have indicated the ability of detecting the absence of fuel rods with high confidence. The method has been verified experimentally, both for a fuel model in laboratory environment and for spent fuel in a fuel handling pool.

Journal Article↗
PubMed2000

Evaluation of OAE-recording as a complementary test method for adults with moderate to profound mental retardation.

The recording of otoacoustic emissions (OAE) was evaluated as a complementary test method for adults with moderate to profound mental retardation (MR). A portable apparatus, ILO 288 Echoport linked to a Compaq LTE 5100 notebook with software ILO 88 V 4.2, was used. Otoscopy and tympanometry were also performed. Criteria for emissions were S/N 3 dB or more and reproducibility 60% or more for at least three frequency-bands. The criteria for partial emissions were the same, but for only one or two frequencies. Two examiners were needed: one to keep the tested person calm and quiet and the other to handle the keyboard. Thirty-eight people with different degrees of MR in connection with other disabilities were included. They had all exhibited incomplete results in a previous hearing screening of more than 1,000 adults with MR. Reproducible transiently evoked OAEs (TEOAE) were recorded from 11 ears (7 people), partial TEOAEs from 6 ears (4 people) and no emissions from 15 ears (10 people). Registration from 24 ears (13 people) could not be evaluated because of too much external and internal noise. Eight people rejected the examination. Only four people showed emissions in both ears. Accordingly, 34 people (89.5%) had to be re-tested or referred for further investigation, 21 of them (55%) because of noisy recordings or no co-operation. It is concluded that the TEOAE-test in its present form cannot fulfil the demands for a functioning test method for this population. In single cases, however, TEOAE-recording can complement other audiological tests.

Acoustic Stimulation↗
PubMed2000

Von Langenbeck or Wardill procedures for primary palatal repair in patients with isolated cleft palate--speech results.

Sixty-six patients operated on for isolated cleft palate were evaluated as adults, and their speech was assessed clinically. Forty-four had undergone a von Langenbeck repair at the age of 7 months and 22 a Wardill repair at the age of 18 months. Speech was judged subjectively by the patients themselves, and perceptual assessment was made by three speech pathologists. The remaining speech problems, mainly hypernasality, were moderate or severe in 7 (16%) of the patients in the von Langenbeck group, and in 7 (32%) in the Wardill group. On the other hand, the patients in the Wardill group had fewer fistulas closed, and fewer velopharyngoplasties. There were no significant differences between the two methods regarding speech in adulthood. The Wardill method produced significantly more scar tissue clinically, which carries the potential risk of inhibition of facial growth. The present speech results will therefore be weighed against the outcome of maxillofacial growth for these patients.

Cleft Palate↗
PubMed1999

In vivo cell recruitment, cytokine release and chemiluminescence response at gold, and thiol functionalized surfaces.

Hydroxylated and methylated surfaces were prepared by the self-assembled monolayer technique (SAM) of alkane thiols on gold. The surfaces were used to evaluate the influence of implant surface chemistry on protein deposition and inflammatory cell response. Implants were inserted subcutaneously in the rat for 3 and 24 h. The surface chemical properties influenced the in vitro rat plasma protein adsorption (ellipsometry/antibody) with few exceptions (albumin not found and fibrinogen always found). The number of recruited cells and their distribution (DNA from implant versus from exudate) was influenced by the different chemistries at 24 h, but not at 3 h. HIS48+, ED1+, ED2+ and small numbers of CD5+ cells were present in the exudate at both time periods (flow cytometry). The cellular oxidative metabolism was low, although cells on -OH surfaces responded with the highest phorbol ester-stimulated chemiluminescence (CL)/DNA. The levels of cytokines IL-1alpha, IL-1beta and TNFalpha (ELISA) were not influenced by material surface chemistry. Sham operated sites had a higher cytokine concentration/DNA compared with exudates from an implant milieu. The results of this study show that surface chemical functionalization modifies specific events in the inflammatory response around implants in soft tissues.

Adsorption↗
PubMed1999

The measurement of venous haematocrit in patients with polycythaemia vera.

OBJECTIVE: In clinical practice, patients with polycythaemia vera (PV) are monitored by measurement of venous packed cell volume (PCV). However, whereas treatment recommendations are still based upon studies in which the results were obtained with the centrifuged microhaematocrit, currently in most instances automated blood cell counters are used to calculate PCV. In a group of patients with polycythaemia we therefore compared the results obtained by the microhaematocrit method with PCV calculated by haematology analysers. DESIGN: The study was carried out on a prospective basis. Duplicate venous blood samples were collected. The centrifuged microhaemotocrit was obtained by using an IEC Micro-MB Centrifuge. Depending on different routine methods used in the participating hospitals, the blood cell counter PCV was calculated using Coulter STKS, Bayer Technicon H2 or H3. SETTING: Patients were included from four Swedish university hospitals: Akademiska (Uppsala), Huddinge and Karolinska (Stockholm) and Sahlgrenska (Göteborg). SUBJECTS: Seventy-four patients with PV and 10 patients with secondary polycythaemia were included and a total of 150 duplicate blood samples were analysed from these subjects. RESULTS: In the 150 measurements the mean blood cell counter calculated PCV was 0.448 +/- 0.037; the mean for centrifuged microhaematocrit was 0.467 +/- 0. 037 and the difference between means was highly significant (P = 6.8 x 10-25). The means for centrifuged haematocrit and calculated PCV differed significantly in the groups of PV patients treated with phlebotomy only, hydroxyurea or radiophosphorous (P < 0.0001, respectively). In PV patients treated with alpha-interferon and in patients with secondary polycythaemia the difference in means did not reach statistical significance (P = 0.07 and P = 0.13, respectively). The groups of patients with MCV <80 fL and >/=80 fL both presented significant differences between means for calculated PCV and centrifuged haematocrit. CONCLUSIONS: If PV patients are monitored with blood cell counter calculated PCV it appears that the therapeutic goal should be to maintain the calculated PCV below 0.43, provided the local differences in calculated PCV and centrifuged haematocrit are of the same magnitude as in this study.

Aged↗
PubMed1999

Computing data about patients with cleft lip and palate.

For clinical research and quality control in the treatment of patients with cleft lip and palate (CLP) we created a register based on commercially available computer components. In this report we present the logical organisation of the system and give some representative examples of its applicability. There is great potential for easy access to data, and presentation.

Adult↗
PubMed1999

Low megakaryocyte ploidy in Ph-positive chronic myelogenous leukemia measured by flow cytometry.

In chronic myeloproliferative disorders, the megakaryocytes differ in size and maturation compared with those of healthy individuals. In the present study, by using a 2-color flow cytometry technique, we determined the frequency of bone marrow megakaryocytes in different ploidy classes in 13 newly diagnosed and untreated patients with Philadelphia chromosome (Ph)-positive chronic myelogenous leukemia (CML) and in 12 healthy volunteers. The results showed a significant difference in megakaryocyte ploidy distributions between these 2 study groups. On the average, patients with CML had 59% of their megakaryocytes in ploidy classes 2N to 8N; in contrast, the healthy volunteers had only 22% of their megakaryocytes in classes 2N to 8N. Two patients with complex Ph translocation and 2 patients with a small clone with a chromosome abnormality in addition to Ph had the same ploidy distribution as those with only Ph translocation. The platelet count did not correlate with the megakaryocyte mean ploidy.

Adult↗
PubMed1998

Millard repair of unilateral isolated cleft lip: a 25-year follow-up.

Twenty-five patients with isolated unilateral cleft lip took part in a follow-up study at a mean age of 28.6 years. All had had a primary, Millard lip repair, at a mean age of 4.6 months. In 20 patients, at least one secondary correction had been undertaken during adolescence. The overall long-term outcome was thought to be good, leaving a fairly inconspicuous fine lip scar and acceptable nose configuration. In half the patients, however, the lip was slightly elongated and the nostrils were still asymmetrical. These findings concurred with the patients' subjective assessments, which showed that appearance of the lip and nose were rated good by 20 (80%) and 16 (64%), respectively. The findings of this study provide a baseline for future evaluation of the results achieved with lip closure by Johanson's technique.

Adolescent↗
PubMed1998

Clinical examination compared with morphometry of digital photographs for evaluation of repaired cleft lips.

Twenty-four adult patients who had been operated on as infants for isolated cleft lip underwent clinical examination combined with photographic documentation using a digital camera. The same predetermined protocol comprising 20 variables describing nasolabial appearance was used for both the clinical examination and the computerised evaluation of the images. The correlation between the two methods is described in the present study. The results obtained with the two methods agreed closely. For metric variables the mean coefficient of correlation was 0.73 and when all measurements were combined, it reached 0.98. Likewise, discrete variables showed a close correlation, with a mean kappa value of 0.72. Variables related to muscular dynamics of the lip can for obvious reasons not be judged from photographs. However, the computerised photographic evaluation was able to detect more precisely even minor angular deviations of the nose and to measure areas such as the areas of the nostrils. We conclude that morphometry of digital photographs is a new valuable clinical tool for the assessment of the nasolabial appearance in patients with cleft lip and palate.

Adult↗
PubMed1997

Multiple quinine-dependent antibodies in a patient with episodic thrombocytopenia, neutropenia, lymphocytopenia, and granulomatous hepatitis.

A 58-year-old man experienced episodes of fever, vomiting, and diarrhea over a 2-year period. The laboratory evaluation during these attacks consistently disclosed thrombocytopenia, leukopenia, and elevated liver enzymes. A liver biopsy performed at one of these attacks showed a typical picture of granulomatous hepatitis. In retrospect, all episodes seemed to be associated with the ingestion of quinine. Indeed, such a correlation was established by a challenge with quinine. By using flow cytometry, quinine-dependent IgG antibodies to platelets were detected in the patient serum. By a two-color flow cytometric assay, the patient serum was also found to hold quinine-dependent antibodies specific for neutrophils, T lymphocytes, and B lymphocytes. Moreover, serum absorbed with neutrophils in the presence of quinine continued to react with platelets, T lymphocytes, and B lymphocytes; serum that was absorbed with mononuclear cells continued to react with neutrophils and platelets. These experiments indicated that the antigen targets were different on platelets, neutrophils, and lymphocytes. Further, the patient serum in the presence of quinine immunoprecipitated surface-labeled platelet proteins with electrophoretic mobilities closely resembling those of glycoprotein (GP) Ib/IX and GPIIb/IIIa. By a modified monoclonal antibody-specific immobilization of platelet antigens assay, the patient serum in the presence of quinine reacted with platelet GPIb/IX and GPIIb/IIIa. Also, the patient serum in the presence of quinine immunoprecipitated an uncharacterized 15-kD double-band from surface-labeled granulocyte proteins. We conclude that our patient's thrombocytopenia, neutropenia, and lymphocytopenia were caused by quinine-dependent antibodies and that these antibodies recognized cell lineage-specific epitopes.

Antibodies↗
PubMed1997

Effects of dermabrasion on acne scarring. A review and a study of 25 cases.

Acne scarring is often treated with dermabrasion and results are evaluated using photographs. We have studied 25 patients before treatment and up to 1 year after dermabrasion for acne scars. Comparisons of results evaluated in different ways show that dermabrasion works best for superficial scars, results for more severe forms of scarring being less predictable.

Acne Vulgaris↗
PubMed1996

Resection margins of 2 versus 5 cm for cutaneous malignant melanoma with a tumor thickness of 0.8 to 2.0 mm: randomized study by the Swedish Melanoma Study Group.

BACKGROUND: The traditional surgical treatment for primary malignant melanoma has often been a wide excision with a margin of about 5 cm. Since the risk of local recurrences is dependent on tumor thickness, thin tumors (<1 mm) have routinely been excised with a narrow margin. For thick tumors, the optimal resection margin is controversial, and can be determined only by prospective, randomized trials. METHODS: The Swedish Melanoma Study Group performed a prospective, randomized multicenter study to evaluate an excision margin of 2 versus 5 cm for patients with cutaneous malignant melanoma with tumor thickness > 0.8 and < or = 2.0 mm. The trial includes 769 patients. Patients with melanomas of the skin of the head, neck, hands, feet, or vulva were not included in the trial. In the event of an excision biopsy for diagnosis, radical surgery was completed within 6 weeks. The median follow-up time was 5.8 years for estimation of survival and 4.0 years for diagnosis of recurrent disease. RESULTS: No significant differences have been observed between the treatment groups regarding local or regional recurrences or survival. CONCLUSIONS: We recommend an excision with a margin of 2 cm for cutaneous malignant melanoma with a tumor thickness > 0.8 and < or = 2.0 mm.

Biopsy↗
PubMed1996

Light chain-restricted autoantibodies in chronic idiopathic thrombocytopenic purpura, but no evidence for circulating clone B-lymphocytes.

In chronic idiopathic thrombocytopenic purpura (ITP) platelet destruction is caused by antibodies directed against platelet membrane glycoproteins (GP), and the predominant autoantigens are known to be GPIb/IX and GPIIb/IIIa. In a recent study we reported that these antibodies frequently had a restricted light chain phenotype, thereby supporting a clonal origin. Similar findings and the presence of clonal B-cell populations in immune thrombocytopenias have been reported by others. In the present study we further explored the hypothesis of clonal B-cell expansions in chronic ITP. Twenty patients with chronic ITP were investigated. Antibodies were detected with an ELISA (MAIPA) specific for GPIb/IX and GPIIb/IIIa; circulating clonal B lymphocytes were assessed by flow-cytometric (FACS) clonal-excess analysis and by analyzing Ig-gene rearrangements (CDR3) with the PCR technique. Nine patients displayed a GP-specific antibody restricted to either kappa or lambda phenotype. However, FACS analysis and Ig-gene rearrangement studies did not disclose any circulating clonal B-cell population. Considering the sensitivity of the FACs analysis and Ig-gene rearrangement for detection of clonal B-cell populations, the hypothesis of clonally derived autoantibodies in ITP is still valid. Most probably, the clonal B-cell expansion responsible for the production of autoantibodies in ITP, if present, is below the detection limit for the techniques employed.

Adolescent↗
PubMed1996

Flow cytometric analysis of megakaryocyte ploidy in chronic myeloproliferative disorders and reactive thrombocytosis.

Megakaryocyte (MK) ploidy patterns were analysed by flow cytometry in 29 newly diagnosed and previously untreated patients with chronic myeloproliferative disorders (MPD) and concomitant thrombocytosis, in 9 patients with reactive thrombocytosis (RT) and in 12 healthy individuals. Unfractionated bone marrow from routine aspirates was used. MKs were identified with a fluorescein labelled monoclonal antibody specific for glycoprotein IIIa (GPIIIa) and DNA was stained with propidium iodide. For the 12 healthy volunteers the mean modal ploidy number was 16 N; the 9 patients with RT displayed an identical MK ploidy pattern. The frequency of MKs with a ploidy > or = 32 N was 45% among the patients with essential thrombocythaemia (ET) compared to 32% among the healthy volunteers (p < 0.001). MKs with ploidy number > or = 64 N, comprising approximately 13% of the total number of MKs, was a characteristic finding in the patients with ET. Similar findings were present in 8 patients with polycythaemia vera (PV). In patients with PV 34% and 6% of the MKs displayed ploidies > or = 32 N and > or = 64 N, respectively. In contrast, a distinct shift towards lower ploidy number, with 63% of MKs < or = 8 N, was found among the 4 patients with chronic myeloid leukaemia (CML). The present results indicate that by using flow cytometric analysis of MK ploidy distribution in patients with thrombocytosis, those with a reactive cause are likely to be discriminated from patients with myeloproliferative thrombocytosis, i.e. PV and ET on one hand and CML on the other hand. The distinction between ET and PV, however, has to be made on other grounds.

Adult↗