Search PubMed⌕ Search

Biomedical subjects

G Lindberg

Publications and source records attributed to G Lindberg.

At least 109 records · Page 6Linked to original sources
PubMed1991

Growth limitation in hybridoma cell cultures: the role of inhibitory or toxic metabolites.

Hybridoma cells usually grow to fairly low cell densities in batch cultures (1-3 x 10(6) cells/ml). The reason for this is either that essential nutritional components of the medium are consumed, or that the cells produce some kind of inhibitory or toxic metabolite. This investigation presents evidence for the latter. Spent medium from cultures of hybridoma cells did not support growth of cells at lower cell densities (1-3 x 10(5) cells/ml). The ability to support cell growth could not be restored by adding additional serum, energy sources (glucose, pyruvate) or L-glutamine. Furthermore, the consumption of amino acids could not account for this growth inhibition. On the contrary, the spent medium contained a substance that inhibited cell growth. This substance or metabolite was found in a fraction eluted from a gel filtration column when spent medium was applied to the column. This substance was found in the spent medium from all hybridoma and myeloma cell lines that were tested. The molecular weight of the substance was about 5 kD. Spent medium from two hybridoma cell lines also contained a substance that was eluted in the same fraction as albumin (67 kD). It is likely that this (or these) substance(s) is responsible for the growth limitation in hybridoma cell cultures.

Amino Acids↗
PubMed1991

Amyotrophic lateral sclerosis in Sweden in relation to occupation.

All cases of ALS in Sweden during the period 1970-1983, i.e., 1961 cases, were compared with an age-stratified random sample of 2245 individuals from the Swedish population. On the basis of census information, the male cases were found to be heterogeneously distributed over occupational groups. Significantly more male cases than expected were found among office workers (OR = 1.8; 34 cases) as well as among farm workers (OR = 1.7; 56 cases). There was a cluster of male cases in agricultural work in one south-western county (OR = 3.4; 25 cases). Significantly more female cases than expected were medical service workers (OR = 1.7; 33 cases).

Adult↗
PubMed1991

The effect of omeprazole and ranitidine on ulcer healing, relief of symptoms, and incidence of adverse events in the treatment of duodenal ulcer patients.

In a Swedish double-blind multicenter study involving 143 patients, the new proton pump inhibitor omeprazole (30 mg taken as a single morning dose) was compared with ranitidine (400 mg b.i.d.). Clinical assessment and laboratory investigations were carried out at 2 and 4 weeks, and again at 6 weeks if patients had not healed earlier. Endoscopy was repeated at two-weekly intervals until the ulcer was healed. The patients in the two treatment groups were well matched prior to treatment. There was a higher ulcer healing rate in the omeprazole group (70%) than in the ranitidine group (55%) after two weeks of treatment. This difference reached statistical significance in 128 patients adhering to the protocol as shown by a logit model analysis with drug, ulcer size and smoking as the prognostic factors (p = 0.04). There were no major differences between the two treatment groups in terms of symptomatic relief. Both drugs were generally well tolerated, and the number of adverse events in the two treatment groups were similar. After healing, 127 patients entered a follow-up study, with endoscopy either after 6 months or on recurrence of symptoms. There was no significant difference between the two treatment groups, with the relapse frequency within 6 months being 39% in the omeprazole group and 47% in the ranitidine group. These results, with a 15 percentage points higher ulcer healing rate for omeprazole as compared with H2-receptor antagonists after two weeks, are in accordance with results reported in other studies.

Duodenal Ulcer↗
PubMed1990

The mortality of motor neuron disease in Sweden.

The age-standardized mortality from motor neuron disease in Sweden doubled from 1961 to 1985. The average annual rate during the period was 1.9 per 100,000 population. The male to female ratio was 1.2:1. The age-specific mortality rates had a peak at 70 to 79 years of age. When each birth cohort was followed up separately over time, the peak was less clear and in some cohorts the mortality rates increased continuously with advancing age. A significant increase of motor neuron disease among men was found in one Swedish county.

Age Factors↗
PubMed1990

Digital ambulatory monitoring of small-bowel motility.

This paper describes a new technique for ambulatory long-term monitoring of small-bowel motility. Intraluminal pressure was measured with a silicon catheter with two strain-gauge transducers spaced 15 cm apart. Pressure data were stored in a portable memory unit. Initial studies showed that a recording frequency of 2 Hz was sufficient for obtaining reliable motility measurements. Twelve-hour recordings of motility in the upper jejunum were done in 12 healthy volunteers. After a 1964-kJ meal the median duration of fed-state motility was 4.6 h (3.4-5.3 h, interquartile range). The activity front of the migrating motor complex propagated with a velocity of 2.7-5.3 cm/min, and the median cycle length was 77 (40-103) min. The frequency of contractions in the activity front was 11.4 (10.9-11.6)/min at the proximal transducer. This new technique enables small-bowel motility to be monitored over longer periods of time and with much less inconvenience to the patient than previously used methods.

Adult↗
PubMed1989

Purification and characterization of the coliphage N4-coded single-stranded DNA binding protein.

We have purified and characterized a single-stranded DNA binding protein (N4 SSB) induced after coliphage N4 infection. It has a monomeric molecular weight of 31,000 and contains 10 tyrosine and 1-2 tryptophan amino acid residues. Its fluorescence spectrum is dominated by the tyrosine residues, and their fluorescence is quenched when the protein binds single-stranded DNA. Fluorescence quenching was used as an assay to quantitate binding of the protein to single-stranded nucleotides. The N4 single-stranded DNA binding protein binds cooperatively to single-stranded nucleic acids and binds single-stranded DNA more tightly than RNA. The binding involves displacement of cations from the DNA and anions from the protein. The apparent binding affinity is very salt-dependent, decreasing as much as 1,000-fold for a 10-fold increase in NaCl concentration. The degree of cooperativity (omega) is relatively independent of salt concentration. At 37 degrees C in 0.22 M NaCl, the protein has an intrinsic binding constant for M13 viral DNA of 3.8 x 10(4) M-1, a cooperativity factor omega of 300, and binding site size of 11 nucleotides per monomer. The protein lowers the melting point of poly(dA.dT).poly(dA-dT) by greater than 60 degrees C but cannot lower the melting transition or assist in the renaturation of natural DNA. N4 single-stranded DNA binding protein enhances the rate of DNA synthesis catalyzed by the N4 DNA polymerase by increasing the processivity of the N4 DNA polymerase and melting out hairpin structures that block polymerization.

Chromatography, Affinity↗
PubMed1989

Better health--but not for all: the Swedish Public Health Report, 1987.

This article is a summary of the Public Health Report submitted to the Swedish Parliament in 1987. Health development, especially that of underprivileged groups, is regarded as an indicator of the quality of social and economic development of the country. Sweden is a very egalitarian country, but in spite of decreasing inequalities in living standards, the Report shows increasing inequalities in health. At the same time, the state has put restraints on health care spending, and the shift in the health care budget toward more primary care has stopped. This development seriously impairs the ability of the health and medical services to cope with inequities described in this Report.

Adolescent↗
PubMed1988

Single case studies in clinical trials.

The single case design offers an interesting alternative to standard methods of performing clinical trials. The opinion of the workshop members was that single case trials would be particularly useful in studies of rare diseases and in studies aimed at generation of hypothesis rather than testing of hypotheses. The single case design was considered to require smaller patient materials than ordinary methods in order to arrive at a valid conclusion about therapeutic effect. Dose ranging (Phase II) studies and studies of heterogenous patient populations were also discussed as possible areas of application for the single case design.

Clinical Trials as Topic↗
PubMed1987

Epidemiology of hepatitis B in Somalia: inference from a cross-sectional survey of serological markers.

Hepatitis B markers were determined by radioimmunoassay in 383 adults from different areas of Somalia and in 135 pregnant females and 428 children from Mogadishu. The highest incidence of HBsAg among adults was among nomadic males (20/85; 23%). The frequencies were lower in males from the agricultural and coastal area, i.e. 16/93 (17%) and 14/98 (14%) respectively. The lowest frequency of HBsAg was among women from the coastal area (6/72; 8%). Among the pregnant women 14 were positive for HBsAg, none of whom had HBeAg. Low levels of positivity for HBsAg were found both among children under 4 years and among those between 4 and 13 years of age - 3/94 (3%) and 5/128 (4%) respectively. In the age group 15-19 years, 50% showed seroconversion from HBeAg to anti-HBe. 7 out of 41 HBsAg carriers of ages over 20 had HBeAg. Early seroconversion from HBeAg to anti-HBe and a low level of HBsAg positivity in children indicate that vertical transmission is not important in Somalia. The low frequency of HBsAg in Mogadishu children may have one of the following explanations: (i) the infection occurs during adolescence, (ii) Mogadishu is a low-prevalence area and the examined adults were not born in Mogadishu, or (iii) a change in hepatitis B epidemiology has taken place in the area during the last 2 decades and the relatively higher prevalence of HBsAg in adults might reflect higher rates of infection in their childhood.

Adolescent↗
PubMed1987

Differential diagnosis of jaundice: applicability of the Copenhagen Pocket Chart proved in Stockholm patients.

This paper shows that an algorithm for differential diagnosis of jaundice developed in Denmark has been successfully transferred for use in a Swedish hospital. The algorithm, which is based on data from nearly 1000 patients, utilises 21 items of information from the medical history, physical examination and blood chemistry. The algorithm recognises four diagnostic groups: benign obstructive jaundice, malignant obstructive jaundice, acute non-obstructive jaundice, and chronic non-obstructive jaundice. To each item of information, a score is attached reflecting its weight of evidence. Summing the scores for the symptoms and signs that are present leads to a probabilistic statement about the diagnosis. Because of missing data in the Swedish patient material, three of the items were excluded from the original algorithm. Corrections were made for differences in the distribution of diseases. In reclassification of 985 Danish patients the modified algorithm's "best bid", i.e. the diagnosis given the highest probability, was correct in 78% of cases. More important, 93% of the cases given a "confident" diagnosis (probability greater than 0.80) were correct. The corresponding figures when the algorithm was applied to Swedish patients were 76% and 93%, respectively. In both series the predicted probabilities were matched by a corresponding proportion of actual diagnostic hits. It is concluded that the algorithm leads to reliable estimates of diagnostic probabilities in jaundice and that the algorithm seems to work well in Sweden also.

Adult↗
PubMed1987

Smoking habits and their confounding effects among occupational groups in Sweden.

Smoking habits among different occupational groups in Sweden were estimated from nation wide surveys of living conditions in 1977 and 1980/81. These surveys were conducted by Statistics Sweden and consist of interviews covering the Swedish population aged 16-74 years. The sample includes about 12,000 persons for each of the two investigations. The results show that those who may be exposed to excess risks in their work environment, smoke more than those in other occupational groups. Transport and manufacturing workers, miners, wood and paper workers and painters, for example, have higher rates of daily smokers than the national average. The highest rates, however, were found among the category of early retired or unemployed. These findings confirm that an appropriate evaluation of occupationally-related diseases affected by smoking must take smoking data into consideration. If smoking data are available from other sources, adjusted work-related risks could be calculated. This presumes the absence of interaction effects. Procedures are given and illustrated. The paper also discusses the declining trends in smoking habits between 1977 and 1980/81 and possible reasons for differences in smoking habits between occupations.

Adolescent↗
PubMed1987

Computer aided diagnosis of jaundice. A comparison of two data bases.

A computer system for probabilistic diagnosis of jaundice was tested on a patient sample from a geographical area different from that for which it was first constructed. 144 consecutive patients with jaundice seen in two Stockholm hospitals were interviewed and examined to record a total of 82 indicants from history, demographic details, physical findings and laboratory tests. Data were compared with those of 319 jaundiced patients previously interviewed and examined at different London hospitals. It was found that disease incidences were different in the two patient samples. There were more patients with acute viral hepatitis, chronic active hepatitis and primary biliary cirrhosis in the London data base whereas the Stockholm data base included significantly more patients with Gilbert's syndrome and alcoholic cirrhosis. Indicant frequencies, standardised for disease incidence, differed with respect to age (Stockholm patients were on average six years older), time from onset of first symptom to hospital admission (Stockholm patients had on average a two-week shorter history of disease) and a number of symptoms such as nausea, vomiting, anorexia, weight loss, itching, pale stools and dark urine which were more frequent among the London patients. Differences in hospital admission policy was regarded as an important reason for the differences in indicant frequency. The results of probabilistic diagnosis were poor. Only 49% of the cases were correctly classified into twelve diagnostic groups. In particular the computer model was poor at separating different causes of malignant bile duct obstruction and at differentiating between malignant and benign bile duct obstruction. However, all cases of acute viral hepatitis were correctly classified and the computer model was 87% accurate in differentiating between medical and surgical jaundice. Reclassification of the 144 patients on their own data showed the computer system to be well calibrated and 97% of the cases were correctly classified according to this procedure. In conclusion, the computer system could not be directly transferred for use in a Swedish hospital but the results of reclassification were sufficiently encouraging to warrant prospective studies.

Adult↗
PubMed1987

Transferability of a computer system for medical history taking and decision support in dyspepsia. A comparison of indicants for peptic ulcer disease.

The transferability of a British data base for differential diagnosis of dyspepsia using data obtained by computer interrogation was tested in 467 Swedish patients. The diagnostic value for peptic ulcer disease of symptoms such as frequent night pain relieved by food or antacids, smoking, family history of ulcer, food relief pain, male sex, and episodic pain was shown to be reproducible. However, for a number of symptoms their value for the diagnosis of peptic ulcer disease could not be reproduced in Swedish patients. The combined value of indicants was tested using a computer based algorithm for calculating diagnostic probabilities. The performance of this algorithm was poor when British data were applied to Swedish patients but reclassification of the Swedish patients on their own data base showed promising results. Crean and colleagues in Glasgow have developed a computer system for automated interrogation of patients with dyspepsia. The system utilises a large number of questions to obtain information regarding a maximum of 160 diagnostic indicants. The symptoms elicited from a patient can be compared with those of a large number of previously examined patients and the probabilities of ten different diagnoses can be calculated. The calculation of diagnostic probabilities is based on scores reflecting the diagnostic value of different symptoms in different diseases. After careful translation of questions the system has been transferred for use in Sweden. The present report is based on data from patients seen during the first two years with the system at a Swedish hospital.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Diagnostic decision-making in the irritable bowel syndrome.

Diagnostic classification problems and work towards a positive diagnosis of the irritable bowel syndrome are reviewed. The absence of a biochemical or morphological marker for this syndrome has led several authors to apply multivariate statistical models in the search for a combination of symptoms that could help in distinguishing the irritable bowel syndrome from other causes of dyspepsia. Despite some limited success in experimental studies the clinical value of porported combinations remains to be proved. Diagnosis of the irritable bowel still rests upon the recognition of key symptoms, rules of thumb, and the exclusion of organic disease.

Algorithms↗
PubMed1986

Bacteriophage N4-coded 5'----3' exonuclease. Purification and characterization.

Bacteriophage N4 DNA replication requires the activity of a phage-induced exonuclease. We show here that the activity is phage coded. We have purified this enzyme to apparent homogeneity. It has a denatured molecular weight of 45,000 and exists in solution as a dimer. Duplex DNA is the preferred substrate which it degrades in a 5'----3' direction to 5' mononucleotides by a distributive mechanism. The enzyme does not act at a nick or a gap; indeed, it requires an end for activity. A possible role for this exonuclease in N4 replication is discussed.

Coliphages↗