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Biomedical subjects

B Lind

Publications and source records attributed to B Lind.

At least 91 records · Page 5Linked to original sources

Integrated personal monitoring of cadmium exposure in Sweden.

Methods for the personal monitoring of human exposure to cadmium from air, food and beverages were studied in a group of 15 non-smoking women in Stockholm. Particles in the breathing zone air and duplicates of all food and beverages ingested were collected during seven consecutive days, as were faeces corresponding to the food ingested. Spot samples of blood and urine were also taken. The main sampling problems were caused by the noise of the personal air monitors and the short operation time of the batteries. On average, dietary cadmium (8.5 micrograms per day) contributed 99% of the total cadmium absorbed. There were large day-to-day variations in intake, most peaks corresponding to the consumption of seafood. Faecal cadmium was shown to reflect the total amount of cadmium ingested. There was a significant (p < 0.05) correlation between cadmium concentrations in blood (median 0.3 microgram/l) and average daily dietary intake of cadmium, but the blood cadmium levels could vary by a factor of four at one and the same average daily intake. The median urinary cadmium level was 0.2 microgram/l.

Adult↗

Biological characterization of infectious molecular clones derived from a human immunodeficiency virus type-1 isolate with rapid/high replicative capacity.

In order to molecularly characterize rapidly and slowly replicating HIV-1 variants, molecular clones were obtained from a rapid/high virus isolate. This isolate, 4803, had only been passaged in peripheral blood mononuclear cells (PBMC) prior to cloning. Molecular cloning was done in bacteriophage lambda-dash using high molecular weight DNA of isolate 4803 infected PBMC. Seven recombinant phages were identified. The clones were found to be related to each other and differed only at 1 or 2 restriction sites (out of 28). The molecular clones were transfected into various cell types by electroporation. The phenotype of progeny viruses was found to be dependent on the cell type used for transfection. Progeny viruses produced by PBMC cultures differed from the parental isolate in that they did not form syncytia and lacked the capacity to replicate in cell lines. Since transfection of PBMC yielded progeny viruses within 1 week, this phenotype is considered to be the true phenotype of the clones. Transfection of the T-lymphoid HUT-78 cell line and of the monocytoid U937-2 cell line yielded progeny viruses after considerable delay (more than 1 month). Progeny viruses from HUT-78 cells were similar to the parental isolate in that they formed syncytia in PBMC and replicated in all cell lines tested. Progeny viruses from U937-2 cells showed an intermediate phenotype in that they replicated in U937-2 but not in T-lymphoid cell lines. These results indicate that molecular clones of a rapid/high virus may have a restricted replicative capacity compared to the parental, genetically heterogenous virus isolate.

Cell Line↗

Personal monitoring of lead and cadmium exposure--a Swedish study with special reference to methodological aspects.

Methods for determining personal exposure to lead and cadmium were tested in Stockholm in 1988. Lead and cadmium in breathing-zone air, 24-h duplicate diets, and feces of 15 nonsmoking women (27-46 years of age) were studied. Blood was collected at the beginning of and immediately after the test period (seven consecutive days). An extensive quality assurance program was included. Most technical problems were encountered in the 24-h collection of airborne particles. The pumps were noisy, and the batteries had to be recharged every 6-8 h. The lead and cadmium levels in feces were found to be useful indicators of the total ingested amounts of these metals. Because of the large day-to-day variation in the dietary intake of lead and cadmium, the sampling period for duplicate diets and feces should be at least 5-6 d.

Adult↗

Spinal cord injuries. Clinical, functional, and emotional status.

Ninety-eight patients with traumatic spinal cord injury, at a median age of 33.5 years (range, 16-72 years), with nonremarkable distributions of neurologic characteristics were investigated at a median of 2.3 years (range, 0.1-23 years) after injury. Functioning, mood disturbances, and overall quality of life were recorded with established self-assessment instruments. Physical dysfunction levels were moderate, being proportionate to neurologic impairment. Psychosocial functions, mood states, and quality-of-life perceptions did not differ from those of a control population sample. Psychosocial function and mood disturbances varied greatly during the first 4 years after injury, but patients' later recordings expressed predominantly a balanced emotional state and a rewarding social life. Progress in this direction consisted of clearly lessened physical dysfunction 1 year after injury and better psychosocial function and well-being after 2 years, whereas patterns of social activities and contacts became gradually less inhibited during a 4-year period after injury. Analysis of complications in patients' histories that affected function and mood showed severe pain to be the only complication that related to lower quality-of-life scores. Urinary incontinence and infection and autonomous dysreflexia related to inhibited self-care performance; spasticity related to impaired ambulation and feeding skills. Gainful employment was the only demographic factor linked to high quality-of-life scores.

Activities of Daily Living↗

The role of fragment X polymers in the fibrin enhancement of tissue plasminogen activator-catalyzed plasmin formation.

When thrombin-mediated fibrin formation and tissue plasminogen activator (t-PA)-mediated fibrinolysis proceed in dynamic interaction, desA-(desB beta 1-42)-fragment X polymers are shown to be the predominant fibrin derivatives present during the rapid second phase of Glu1- and Lys78-plasminogen activation. To further investigate the effect of this intermediate, a method was developed for the production and purification of fibrinogen-derived desA-(desB beta 1-42)-fragment X, deprived of both COOH-terminal A alpha-chains, but still capable of thrombin-mediated polymerization. DesA-(desB beta 1-42)-fragment X polymer was compared to intact fibrin with regard to its stimulatory effect on Glu1-, Lys78-, and Val443-plasminogen activation, and its binding of Glu1- and Lys78-plasminogen. Pure fragment X polymer gave rise to a biphasic activation pattern like that of fibrin, demonstrating similar kinetics of rapid phase activation. The dissociation constant for the binding of plasminogen to the effector decreases by a factor of 14, and the stoichiometry increases by a factor of 2 upon plasmin-catalyzed cleavage of both native Glu1- to Lys78-plasminogen, and fibrin to fragment X polymer. We conclude that desA-fibrin protofibril formation is sufficient to initiate fibrin enhancement of t-PA-catalyzed plasminogen activation, and that optimal stimulation depends on further plasmin-mediated modification of the fibrin effector to desA-fragment X-related moieties. Optimal stimulation is dependent on the presence of the kringle 1-4 domains of plasminogen and probably results from altered and increased binding of both plasminogen and t-PA to the modified effector.

Amino Acid Sequence↗

Thrombin-antithrombin III-complex & fibrin degradation products in plasma: surgery and postoperative deep venous thrombosis.

Thrombin-antithrombin-III complexes (TAT) & D-dimer in plasma, and fibrin(ogen) degradation products (FDP) in serum, were measured in 48 patients subjected to total hip arthroplasty. Blood samples were collected on days -1, 0, 1, 3, 7 and 10. Five patients developed postoperative deep vein thrombosis (DVT) diagnosed by venography. A characteristic pattern of TAT and D-dimer secondary to surgery was demonstrated. A poor correlation was found between ELISA- and latex-D-dimer concentrations after the operation. Patients with DVT had significantly higher TAT-levels preoperatively, and on day 0, 7 and 10. The concentration of FDP was significantly elevated in patients with DVT on day 7 and that of ELISA D-dimer on days 0 & 10. None of the assays are clinically valuable for purposes of postoperative screening for DVT. The preoperative plasma TAT concentration may represent a valuable predictive marker of postoperative DVT.

Adult↗

Naturally occurring HIV-1 isolates with differences in replicative capacity are distinguished by in situ hybridization of infected cells.

Replication of human immunodeficiency virus type 1 (HIV-1) isolates in peripheral blood mononuclear cells (PBMC) has been studied by in situ hybridization using the riboprobe BH10-R3 from HTLV-IIIB. Two series of isolates were tested: (a) 20 isolates from individuals with varying severity of HIV-1 infection and (b) sequential isolates from 5 subjects showing signs of clinical progression over a 45 month observation period. The results show that HIV-1 isolates with distinct replicative capacity can be distinguished by the intensity of radioactive labeling over single infected cells after in situ hybridization. Sequential isolates from patients with clinically progressive HIV-1 infection show a gradual increase in replicative capacity over time. In PBMC cultures infected with such sequential isolates, intensity of radioactive label over single infected cells increases and is strongest with isolates obtained at the time of low CD4 counts in blood. The results suggest that the restriction of virus replication that operates in the early stages of HIV-1 infection is gradually lost with progression of the disease.

HIV Infections↗

Dental amalgam and mercury.

Mercury concentration in intraoral air and urine of seven females with dental amalgam was measured before and after intake of one hard-boiled egg. A considerable decrease in mercury concentration in intraoral air was found. Twenty women with about equal dental amalgam status, with or without subjective symptoms related to dental amalgam, were also studied. Mercury concentrations in intraoral air and urine were measured. For all the 27 women the basal intraoral air concentration of mercury ranged over 0.6-10.4 micrograms/m3 (median value 4.3 micrograms/m3). This corresponds to a release of 0.02-0.38 ng/s (median value 0.16 ng/s). In urine, the mercury concentration varied from less than 0.8-6.9 micrograms/g creatinine (median value 1.9 microgram/g creatinine). Data from both parameters were significantly correlated to the total number of teeth areas with dental amalgam. Protein values in urine indicated no renal damage. Maximum concentrations of mercury vapour in intraoral air for the 27 women who had chewed chewing gum for 5 min varied between 2-60 micrograms Hg/m3 (median value 19 micrograms Hg/m3). This corresponds to 0.07-2.20 ng Hg/s and a median value of 0.70 ng Hg/s.

Adult↗

Normal urinary albumin excretion in recently diagnosed type 1 diabetic patients.

The urinary excretion of albumin and retinol binding protein were measured in 51 recently diagnosed Type 1 diabetic patients and 48 control subjects, matched for age and sex. The diabetic patients, admitted consecutively to the Steno Memorial Hospital, were all studied 3 to 6 months after the onset of diabetes. Urinary albumin excretion (median and 95% confidence interval) was similar in the diabetic patients and normal control subjects (8 (6-11) vs 8 (6-11) mg 24-h-1, NS). Four diabetic patients had urinary albumin excretion in the microalbuminuric range of 30-300 mg 24-h-1. There was no significant difference between the two groups in urinary excretion of retinol binding protein. The distribution among the individuals of both urinary proteins was positively skewed and similar in the two groups. In conclusion, no significant differences in the urinary excretion of albumin and retinol binding protein were found between recently diagnosed Type 1 diabetic patients and normal subjects.

Adult↗

Alleviation of labor pain in Norway. An interview investigation in 1969 and 1986.

In 1969 the Scan-Gallup institution interviewed a random sample of 503 women from all parts of Norway who had given birth during the last 24 months. Cesarean sections and forceps deliveries were excluded. The interviews revealed that 69% of the women were left unattended for a considerable part of the delivery, that their husbands were present at only 6% of the births, and only 31% of the women received any kind of analgesia. None were given an epidural block. Nevertheless, 80% of the mothers subsequently said they were satisfied with the treatment and care. Of the 20% dissatisfied, 70% complained of lack of attention, but only 17% drew attention to lack of analgesia. The same investigation has been repeated in 1986 by the same institution and using the same questions. This time the interviews disclosed a completely different picture. 83% of the women were attended by someone all the time during their births, the child's father was present at 86% of the births, 75% of the mothers had received some kind of analgesia, and 14% received epidural block. Nevertheless, the number of satisfied mothers was no greater than in 1969. In 1986 the dissatisfied complained of unfriendly midwives, and lack of sympathy, reassurance and support. Only 15% complained of lack of analgesia, similar to the 1969 finding.

Anesthesia, Obstetrical↗

Normal range of motion of the cervical spine.

To evaluate the normal range of motion of the cervical spine, 70 healthy subjects were studied using radiography and clinical examination. An equal number of men and women were studied; age ranged from 12 to 79 years. Radiographs were taken in the lateral projection during maximal flexion and extension. In the frontal projection, radiographs were taken during maximal bending to the left and right. The radiographs were analyzed on a digitizing tablet linked to a computer, using preset points to indicate the motion between the vertebrae. The intraobserver error of measurement was +/- 1.8 degrees. The range of axial rotation was measured with the aid of a compass placed on the subject's head. The intraobserver error of measurement with this technique was +/- 6 degrees. The largest intersegmental flexion-extension motion occurred between C4/C5 and C5/C6. A linear decrease of motion in all directions, except in flexion, was found with age. There was no statistically significant difference in motion for men and women. The reliability of methods is discussed.

Adolescent↗

Shaping of arbitrary dose distributions by dynamic multileaf collimation.

Traditionally, the shaping of non-uniform dose distributions has been performed by using wedges or compensating filters. The advent of high resolution multileaf collimators may largely eliminate the need for material attenuators for modification of the beam. This is achieved by a new technique for the shaping of arbitrary dose distributions by dynamic motion of the collimator leaves. By employing narrow elementary slit beams that correspond to the smallest possible opening of the multileaf collimator, the optimal density of such slit beams, i.e. opening density, can be determined automatically using a newly developed inversion algorithm. The present method has two major advantages (1) internal structures in the field can be created, controlled solely by steering the collimator leaves, (2) the opening density determined by the algorithm never gives rise to underdosage: this is important from a radiobiological point of view.

Humans↗

Forces and motions across the neck in patients treated with halo-vest.

A prospective study of the sagittal plane motion of the cervical spine, stabilized with a halo-vest was performed in 31 consecutive patients with unstable cervical spine injuries. Motion was measured in lateral radiograms taken with the patient in different positions and while performing various exercises. The extreme angle in extension and flexion in each motion segment, in any of the exercises, was measured and the sum of this maximal motion in each segment, between occiput and C6, was noted (maximal cervical motion). Distraction-compression forces across the neck were studied simultaneously with the motion study in the last 20 patients of the series. Strain gauges were mounted on the two vertical rods of the halo-vest and the forces were correlated to the motion of the spine. We found a mean maximal cervical motion of 51 degrees (about 70% of the normal motion). The halo-vest restricted the motion the most below C2 and the least above C2. In the supine position, all patients had a distraction force across the neck (mean: 51 N) that decreased in some exercises (eg, sitting, standing) and increased in others (eg, arm lifting, shoulder shrugging). Both the motion and the force varied widely between different types of exercises. There was a maximal variation of 175 N between the exercises. A positive correlation was found (r = 0.8) between the distraction force in the supine position and the maximal cervical motion. No significant differences of motion in the cervical spine were found between the rehabilitation exercises and common activities of daily living.

Adolescent↗

Halo-vest treatment of unstable traumatic cervical spine injuries.

Eighty-three patients with unstable cervical spine injuries were treated with halo-vest stabilization in a prospective consecutive series during a 10 year period. At the follow-up 2-7 years after the trauma, six patients had died and eight patients had been surgically stabilized. Sixty-seven of the remaining 69 patients (97%) were subjected to the follow-up performed with validated protocols. All patients but three were reexamined clinically and radiographically. Flexion-extension motion and sidebending of the neck was measured radiographically. Rotation was measured with the aid of a compass placed on top of the head of the patient. Forty-four patients (53%) had initial neurological deficit, 26 with tetraparesis. The age range was 13-89 years and the male/female ratio was 2/1. The halo-vest treatment period was 10-12 weeks. The 1 year healing rate was 90%. Seven nonunions occurred, all in fracture types known to be prone to nonunion. Complications during the treatment were usually minor, with pin problems being the most frequent (pin loosening 60%). At the follow-up, approximately 80% of all patients had complaints of local neck symptoms. Pain at the extremes of neck motion and stiffness was the most frequent. The symptoms were mild and did not usually have any major impact on return to work or leisure activities. Seventy-five percent of patients with incomplete cord lesions and useless muscle function improved to useful function. The patients had a statistically significant decrease of rotation (18%) and sidebending (18%) of the neck but normal flexion-extension motion when compared to the normal.

Adult↗

Distinct replicative and cytopathic characteristics of human immunodeficiency virus isolates.

According to their capacity to replicate in vitro, human immunodeficiency virus (HIV) isolates can be divided into two major groups, rapid/high and slow/low. Rapid/high viruses can easily be transmitted to a variety of cell lines of T-lymphoid (CEM, H9, and Jurkat) and monocytoid (U937) origin. In contrast, slow/low viruses replicate transiently, if at all, in these cell lines. Except for a few isolates, the great majority of slow/low viruses replicate in peripheral blood mononuclear cells and Jurkat-tatIII cells constitutively expressing the tatIII gene of HIV-1. The viruses able to replicate efficiently cause syncytium formation and are regularly isolated from immunodeficient patients. Poorly replicating HIV isolates, often obtained from individuals with no or mild disease, show syncytium formation and single-cell killing simultaneously or, with some isolates, cell killing only.

Acquired Immunodeficiency Syndrome↗