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Biomedical subjects

A Berglund

Publications and source records attributed to A Berglund.

At least 55 records · Page 3Linked to original sources
PubMed1994

Release of elements due to electrochemical corrosion of dental amalgam.

The corrosion pattern of dental amalgam in aqueous media was interpreted theoretically by means of log(ai/a(ref))-pe diagrams. The definitions on which the diagrams were based were given, and their features were described. All sparingly soluble compounds which were expected to be formed in reactions with the solvents considered were listed. All the corrosion products reported in the current literature were found to be formed, and the conditions for their formation were established. It emerged that it was necessary to exclude other sparingly soluble compounds with theoretically might be formed. Two compounds, CuSCN and AgSCN, which have not been reported previously were found to be possible corrosion products. Corrosion products containing mercury compound cannot be formed on amalgam restorations with no metallic contact with other materials.

Copper↗
PubMed1994

Reduced mercury vapor release from dental amalgams prepared with binary Hg-in liquid alloys.

For the past ten years, the amounts of mercury vapor released from dental amalgams and the possibility of side-effects caused by these amounts have been discussed. Although no adverse health effects have been substantiated from these minute amounts, besides rare cases of allergies, this release should be reduced. The aim of this study was to reduce the mercury evaporation from a high-copper amalgam during setting by triturating the alloy powder with binary Hg-In liquid alloys having various indium concentrations set at 0, 5, 10, 20, 30, 40, and 50 wt%. Specimens (n = 4) were made for each amalgam according to ANSI/ADA Specification #1 and placed into a measuring chamber kept at 36.5 +/- 0.5 degrees C, through which a continuous air flow of 0.75 L/min was pumped. The total mercury release was measured during the setting period, according to the method described by Ferracane et al. (1992). Four additional specimens were prepared from a modified 14% Indisperse amalgam powder for the purpose of comparison. The results showed that the release of mercury vapor decreased with increasing indium concentrations, and that the amalgams made with the Hg-In liquid alloy with 10% In or more released significantly less mercury than the modified 14% Indisperse. The method of mixing indium in mercury prior to trituration appeared to be another effective method for reducing mercury evaporation during setting. The reduced mercury release may be explained by a reduction of mercury concentration in the structure, a reduction of vapor pressure for the mercury in the matrix phases, or more efficient formation of a surface oxide layer.

Dental Amalgam↗
PubMed1994

Is carbohydrate-deficient transferrin in serum useful for detecting excessive alcohol consumption in hypertensive patients?

The aim of this study was to examine the diagnostic usefulness of carbohydrate-deficient transferrin (CDT) in serum in a cross-sectional study of 439 treated hypertensive men. We related the results to alcohol intake by questionnaire and to biochemical and hemodynamic measurements known to reflect excessive alcohol consumption. The diagnostic sensitivity and the specificity for high alcohol intake (> or = 24 g/day of ethanol) were 44% and 87%, respectively. The group with reported high alcohol intake (n = 32) was characterized by hemodynamic and biochemical changes typical of alcohol abuse. The corresponding profile for the patients with increased serum CDT concentrations (n = 70) was different in several respects, indicating a considerable number of false-positive tests. We conclude that serum CDT determination had low sensitivity and specificity for excessive alcohol consumption in this group of hypertensive patients. The results illustrate the importance of evaluating new laboratory methods in unselected patient populations before drawing any conclusions about their clinical value.

Aged↗
PubMed1993

Intracellular calcium oscillations induced in a T-cell line by a weak 50 Hz magnetic field.

Applied weak magnetic fields have been shown to affect cellular activity on several levels, but the mechanisms involved remain elusive. We have decided to study an early signal transduction event in the human T cell line Jurkat; oscillations of free [Ca2+]i, of the type seen by crosslinking the CD3 complex. Cells were exposed to a 50 Hz, 0.1 mT, sinusoidal magnetic field while intracellular free calcium was measured in individual cells, using fura-2 as a probe. An acute response was observed with oscillatory increases in [Ca2+]i, which subsided when the field was turned off. The effect of the magnetic field on [Ca2+]i was comparable to that achieved by an anti-CD3 monoclonal antibody.

Antibodies, Monoclonal↗
PubMed1993

Failure to detect early breast cancer using in vitro nuclear magnetic resonance spectroscopy of plasma.

Water suppressed proton nuclear magnetic resonance (1H NMR) spectroscopy of human plasma has been described as successful in detection of malignancy. We designed a prospective study to test the hypothesis that in vitro NMR spectroscopy has a high sensitivity for detecting early breast cancer. One hundred and thirty-five women were referred for breast biopsy due to abnormal mammograms. One hundred of these were recruited through a population-based mammography screening project. Sixty-nine of 135 women were found to have breast cancer and their average line width of the methyl and methylene resonance in the plasma were compared to those women who had a benign or normal histopathology in the biopsy and to the line width for 100 healthy subjects from the same population. The mean line width at a half-height of the methyl and methylene resonances of the serum lipoprotein lipids in the NMR spectrum did not differ appreciably between the groups. The line width correlated highly with the serum triglycerides, but correction for the level of triglycerides did not improve the diagnostic accuracy of the line width. Receiver-operating characteristic analysis revealed a sensitivity of 61% and a false positive rate of 43% at the most beneficial cut-off of line width (39.7 Hz). In vitro NMR spectroscopy in our hands was thus not a useful diagnostic tool in patients with early breast cancer.

Aged↗
PubMed1993

An in vitro and in vivo study of the release of mercury vapor from different types of amalgam alloys.

The aim of the in vitro part of the study was to measure the rate of release of mercury vapor from different types of dental amalgam in air, and in air during cyclic dipping into isotonic saline solution or Fusayama solution. The measurements were carried out by means of the Mercollector/Mercometer system, based on atomic absorption spectrophotometry. Both new (age approximately 2 months) and old (age approximately 1.5 years) amalgam specimens were studied. The variations in the rate of release of mercury vapor in air during cyclic dipping into aqueous media were most pronounced during the first day of the 10-day period studied. In air during cyclic dipping into the aqueous media, the conventional amalgam specimens released mercury vapor at lower rates over the whole period than did the dispersed and single-composition types studied. The aim of the in vivo part of the study was to determine the daily release of mercury vapor from amalgam restorations made of alloys of the same types and batches as those used in the in vitro part of the study. A series of measurements was carried out on each of eight subjects before and after amalgam therapy. None of the subjects was occupationally exposed to mercury. The subjects had to follow a standardized schedule for 24 h, where they ate, drank, and brushed their teeth at predetermined times (Berglund, 1990). The amount of mercury vapor released per time unit was measured at intervals of 30-45 min. Samples of urine and saliva were analyzed formercury.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Human fibroblasts lacking trans-stilbene oxide active glutathione transferase exhibit increased cell death when exposed to polycyclic aromatic hydrocarbons.

Glutathione transferases (GST) are detoxifying enzymes who act with many endogenous and exogenous substances such as polycyclic aromatic hydrocarbons (PAH). The GST activity towards trans-stilbene oxide (GST-tSBO) is inherited in an autosomal dominant fashion and can be separated in high (GST-positive) and low (GST-negative) phenotypes when measured in blood. Human fibroblast cultures were established from males matched for age, smoking habits and clinical manifestations of atherosclerosis. Matched pairs of GST-negative and GST-positive fibroblasts were studied. There was a very strong correlation between the levels of GST-tSBO in peripheral blood and in cultured fibroblasts within the same individual. When fibroblasts were exposed to benzo(a)pyrene (BP) or dimethylbenzanthracene (DMBA) GST-negative cells produced relatively more collagen than GST-positive cells. GST-negative fibroblasts showed a greater cell death than GST-positive fibroblasts as well among controls as after exposure to PAH. It is concluded that lack of GST-tSBO is easily discriminated in cultured skin fibroblasts. GST-negative and GST-positive fibroblasts showed different susceptibility towards some toxic stimuli that might be of importance in atherogenesis.

Aged↗
PubMed1992

Weight reduction versus antihypertensive drug therapy in obese men with high blood pressure: effects upon plasma insulin levels and association with changes in blood pressure and serum lipids.

OBJECTIVES: First, to compare dietary and antihypertensive drug treatment in obese men with mild hypertension with respect to effects upon insulin, glucose, lipid metabolism and blood pressure. Second, to test the hypothesis that in the diet group changes in blood pressure and serum lipid concentration were associated with changes in plasma insulin concentration. DESIGN: A 6-week run-in period followed by random assignment to either diet or drug treatment, lasting for 1 year. Blood pressure measurements were performed blind after 5 and 45 min rest, and during isometric exercise. Plasma insulin and blood glucose concentrations were measured before and after an oral glucose load. SETTING: Outpatient clinic in a city hospital. PATIENTS: Sixty-four men aged 40-69 years with a body mass index > or = 26 kg/m2 and with a diastolic blood pressure of 90-104 mmHg when untreated were recruited (screening after an advertisement in a newspaper). Exclusion criteria were diabetes mellitus, organ damage secondary to hypertension and diseases that may have interfered with compliance and the interpretation of results. Sixty-one patients completed the study. INTERVENTIONS: Dietary treatment was based upon weight reduction and sodium restriction. Drug treatment used a stepped-care approach with atenolol as first choice drug. MAIN OUTCOME MEASURES: Absolute reductions in blood pressure, plasma insulin, blood glucose, serum lipid concentration and the waist:hip circumference ratio. RESULTS: Mean body weight decreased in the diet group and increased in the drug-treatment group. Plasma insulin concentrations, the waist:hip circumference ratio and serum lipid profile improved in the diet group compared with the drug group. Blood pressure control was significantly better in the drug group. In the diet group the changes in mean arterial pressure after 5 min rest and serum triglyceride levels correlated with changes in plasma insulin concentrations independent of changes in body mass index or body weight. CONCLUSIONS: Diet treatment was inferior to drug treatment in controlling hypertension, but superior in lowering plasma insulin concentrations and improving the serum lipid profile. The hypothesis of a relation between changes in blood pressure, serum triglycerides and plasma insulin was supported.

Adult↗
PubMed1992

Release of mercury vapor from dental amalgam.

Because of its long-term clinical use there is more information and research data available about dental amalgam than about any other dental restorative material. However, on and off the safety of dental amalgam has been called in question and during the 80's the mercury controversy came to the fore, not only within the profession but also among the general public. Sources of mercury vapor contamination within dentistry were identified and attempts made to evaluate the contributions to the daily mercury uptake which can be attributed to dental amalgam. Mercury can be released from dental amalgam by evaporation and electrochemical corrosion as well as from amalgam particles which have been swallowed. A major route for mercury uptake from amalgam restorations is through inhalation of mercury vapor. The present study focused on experimental and analytical difficulties associated with the measurement of mercury vapor released in the oral cavity. A careful methodological study of the kind of source of mercury vapor that is prevalent and on the methods for measuring the intra-oral release of mercury vapor was carried out. With this as a basis quantitative determinations of the release rate of mercury vapor from amalgam restorations were made on healthy human subjects not occupationally exposed to mercury. The daily uptake of mercury from inhaled mercury vapor was calculated and salivary and urinary mercury levels were determined. In addition the release rate of mercury vapor from different types of amalgam was studied in vitro and in vivo. The findings may be summarized as follows: The only relevant measurable quantity when determining the mercury vapor released from amalgam restorations is the amount released per time unit, i.e. the amount of mercury vapor collected during intra-oral sampling is proportional to the sampling time. The diffusion of mercury atoms inside an amalgam restoration results in the formation of a concentration gradient in the surface of the amalgam. This mercury diffusion is the rate-determining step for mercury vapor release in the long run. In the short run the mercury concentration gradient prevalent on the amalgam surface on the measuring occasion is the apparent rate-determining step. The daily uptake of mercury from inhaled mercury vapor released from dental amalgam seems to make a very small contribution to the total body burden of mercury, in comparison with what can be tolerated in the work environment. The in vitro results revealed obvious differences regarding the release rate of mercury vapor from dissimilar amalgam types.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1991

Time trends in incidence rates of acute, non-traumatic extremity ischaemia: a population-based study during a 19-year period.

Time trends in the occurrence of acute limb ischaemia were studied from 1965 to 1983 in a defined geographical area in Sweden. Data were obtained from a computerized register which covers all instances of inpatient care for a population of 1.3 million. Analysis based on 5394 first admissions for acute arterial occlusion revealed that the annual number increased by 2.7 per cent yearly in women and 3.9 per cent in men whereas the age-adjusted incidence remained stable for women and increased by 2.6 per cent yearly for men. A study of 1189 patients who underwent surgical procedures showed that the annual number of embolectomy procedures increased 7.6 per cent for females and 8.6 per cent for males. The corresponding age-adjusted incidence rose annually by 3.0 per cent for women and by 7.5 per cent for men. The introduction of the Fogarty catheter and an increasing interest in vascular surgery may have contributed to the increasing rates of operations during the period of study.

Adult↗
PubMed1991

Cardiovascular effects of weight reduction versus antihypertensive drug treatment: a comparative, randomized, 1-year study of obese men with mild hypertension.

The aim of the study was to compare cardiovascular effects of weight reduction and sodium restriction with antihypertensive drug treatment in obese middle-aged men with mild hypertension in an open randomized trial lasting for 1 year, preceded by a 6-week run-in period. In the diet group (n = 31), weight decreased by 7.8 kg and salt intake by 2 g/day. In the other group (n = 30), treatment was structured with atenolol as the first line drug. The differences in antihypertensive response were highly significant when measured as casual blood pressure, with drug treatment being favoured. Echocardiographic estimations of left ventricular morphology and function showed no difference in effects between the two treatment modalities. Further analyses showed that the presence of previous antihypertensive treatment was modulating the effect of intervention on left ventricular mass. The response to treatment in plethysmographic estimations of resistance at maximal dilatation in the forearm did not differ between the groups. We conclude that drug treatment was superior to the diet regimen in controlling hypertension, that no differences were observed in effects on cardiovascular structure and that previous antihypertensive treatments seems to be a potent confounding factor that should be taken into consideration in future studies.

Adult↗
PubMed1991

Hypoglycaemic episodes during intensified insulin treatment: increased frequency but no effect on cognitive function.

Ninety-seven patients with insulin dependent diabetes mellitus (IDDM) were randomized to intensified conventional treatment (ICT, n = 44) or regular treatment (RT, n = 53). The mean HbA1c level (+/- SEM) was reduced from 9.5 +/- 0.2% to 7.4 +/- 0.1% in the ICT group (P less than 0.001), and from 9.4 +/- 0.2% to 9.0 +/- 0.2% (P less than 0.01) in the RT group. The difference between the groups was significant (P less than 0.001). During a period of 3 years, 57% of the ICT patients (95% confidence interval 44-73%) and 23% of the RT patients (95% CI, 11-34%) (P less than 0.001) had at least one episode of serious hypoglycaemia, with the need for third-party assistance or resulting in coma. Eighteen of the 32 ICT patients who initially had adrenergic symptoms during hypoglycaemia changed to predominantly neuroglycopenic symptoms. This was the case with only 8 of 38 RT patients (P less than 0.01). The change in symptoms was related to the increased frequency of serious hypoglycaemia, but neither symptoms nor frequency of hypoglycaemia bor any relationship to insulin dose, body mass index, duration of diabetes or autonomic nerve function. The results of several neuropsychological tests did not differ between the groups at baseline, and did not change during the study. There were no signs of deteriorating cognitive function in the patients with serious hypoglycaemic episodes.

Adult↗
PubMed1991

Increased smooth muscle cell proliferation by dimethylbenzanthracene is correlated to variations in activity of ornithine decarboxylase but not arylhydrocarbonhydroxylase.

Polycyclic aromatic hydrocarbons of cigarette smoke have been suggested to be involved in atherogenesis. After being converted to epoxides by monooxidases in the arterial wall the hydrocarbons may exert toxic or mutagenic effects on the smooth muscle cells (SMC). In a previous study we found that dimethylbenzanthracene (DMBA), an inducer of arylhydrocarbonhydroxylase (AHH), increased SMC proliferation and viability. In the present work we intended to study whether these effects were mediated by AHH. Alpha-naphtoflavone (ANF), a non specific AHH inhibitor, decreased SMC proliferation. The effects of ANF were totally counteracted by serum, partially by albumin and not at all by platelet derived growth factor. AHH activity was not detectable nor basally nor after induction in SMC, and this made us conclude that the effects of DMBA and ANF on SMC proliferation were not mediated by AHH. On the other hand the activity of ornithine decarboxylase was influenced by DMBA and ANF in parallel to proliferation, suggesting the involvement of this enzyme in the described DMBA effects on SMC proliferation. This mechanism might be of relevance for the pathogenesis of atherosclerosis especially in relation to cigarette smoking.

9,10-Dimethyl-1,2-benzanthracene↗