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Biomedical subjects

B Lindqvist

Publications and source records attributed to B Lindqvist.

At least 37 records · Page 2Linked to original sources

Torque reaction in angled nutrunners.

In the process of tightening a joint, the angled nutrunner acts on the operator with a torque reaction in the final stages of the tightening sequence. In the following series of experiments, the torque reaction of a machine acting on various joints is studied. A distinctive feature of the torque reaction is that the handle of the angled nutrunner causes a rapid displacement. The amplitude and time aspect of this displacement depend on the stiffness of the joint (whether it is hard or soft), and the movement of the handle depends on how the operator is holding it. How the operator responds to the torque reaction depends upon, among other things, the displacement amplitude as well as the torque level of the machine. Because of this, the displacement amplitude can be used as a measure of the operator's discomfort.

Journal Article↗

Ultrafiltration failure and dialysate glucose in CAPD.

This study was performed to evaluate the use of the glucose concentration versus glucose absorption in the dialysate to estimate ultrafiltration efficacy. In 26 patients (16 men, 10 women) on continuous ambulatory peritoneal dialysis, a total of 128 dwells were investigated. Each dwell lasted 5 hours, using 2 L of peritoneal dialysis fluid containing 140 mmol/L glucose. After the dwell, the removed peritoneal dialysis fluid was weighted. The concentrations of creatinine and glucose and the total amount of glucose were analyzed. The mean concentration of dialysate glucose for the whole group after a 5-hour dwell was 38.9 +/- 8.9 (SD) mmol/L. The ultrafiltration volume was inversely correlated to the glucose absorbed (r = -0.59, p = 0.002), but was not significantly correlated to the glucose concentration in the dialysate (r = 0.40, p = 0.057). The ultrafiltration volume was not related to the creatinine concentration in the dialysate or the body weight. The average dialysate glucose did not change during a one-year observation time. Patients with diabetes mellitus had significantly lower glucose absorption than nondiabetics (p = 0.045), and patients with low ultrafiltration efficacy had significantly greater glucose absorption than those with normal and high ultrafiltration (p = 0.038). There was no difference between those who had those who had not suffered from peritonitis. The results indicate that the glucose absorption from the dialysis fluid is the best parameter to calculate the peritoneal ultrafiltration efficacy and not the glucose concentration currently used.

Adult↗

Bacteriophage P2 and P4 morphogenesis: protein processing and capsid size determination.

An interesting feature of the bacteriophage P2-P4 system is the switch in size between a large P2 (60 nm) and a small P4 (45 nm) capsid. We have investigated whether the protein processing reactions cleaving the primary translation product gpN to several capsid proteins (h1, h2, and N*) are involved in this switch. Using antibodies specific against gpN and its derivatives we have identified all the structural components of mature P2 and P4 particles that are derived from gpN. Our estimate of the relative amounts of gpN derivatives suggests that the previously identified minor capsid proteins h1 and h2 can only be essential structural components of the P4, and not the P2, capsid. Nevertheless, the relative amounts are similar in vivo during a P2 and a P4 infection. This indicates that the switch in head size is not caused by the presence of elevated amounts of h1 and h2 during P4 morphogenesis. We have also identified the sites where gpN is cleaved to its derivatives h1, h2, and N*, ascertaining that the cleavage sites are the same in P2 and P4. Our results indicate that the processing reactions are not directly involved in the head size determination mechanism.

Amino Acid Sequence↗

Mandibular function before orthodontic treatment.

Two-hundred-and-forty-five consecutive prospective orthodontic patients and 245 controls matched for age, sex, and residence, but with minor need of orthodontic treatment, were examined. The functional examination of the masticatory system was made according to Carlsson and Helkimo (1972), and Helkimo (1974). According to dysfunction index (Helkimo, 1974), 33.5 per cent of the patients and 21.6 per cent of the controls had a moderate, and 18.9 and 7.8 per cent respectively, a severe dysfunction. The corresponding figures for symptoms were 16.7 and 4.9 per cent respectively. In the patient group the frequency of signs and symptoms was higher in the older age group and in the girls. Orthodontic patients appeared to be at greater risk of craniomandibular disorders (CMD) than individuals with minor need of treatment.

Adolescent↗

Detection of genital papillomavirus types by polymerase chain reaction using common primers.

We describe the detection of eight genital human papillomavirus (HPV) types, including HPV16 and HPV18, by PCR amplification of a 323 base-pair region of the genome within the L1 open reading frame (ORF). The primer sequences are: TGYAAATATCCWGATTWTWT and GTATCWACMACAGTAACAAA. The method will detect purified HPV16 DNA down to a concentration of as little as a single molecule in 100 microliters. The method is also applicable to purified DNA and crude lysates from tumour biopsies. Typing of the PCR product can be achieved with specific oligonucleotide probes.

Base Sequence↗

Characterization of phiLC3, a Lactococcus lactis subsp. cremoris temperature bacteriophage with cohesive single-stranded DNA ends.

The temperate bacteriophage phiLC3, isolated from Lactococcus lactis subsp. cremoris, has an isometric head and a flexible tail containing 1 major protein and 8 minor proteins. Infection of a permissive L. lactis host strain yields a burst of about 50 phages per infected cell with a latent period of 60 min. A detailed restriction map of the phage chromosome was constructed by using 12 different restriction enzymes. The phage chromosome is a 33-kb linear double-stranded DNA molecule with unique cohesive ends and with a G + C content of 36.5%. Chemical sequencing of the DNA ends revealed 13-base 3' extended complementary single strands with a relatively high percentage of G + C. Pulsed-field gel electrophoretic analysis of DNA from a strain lysogenized with phiLC3 was used to localize the prophage to a 320-kb BamHI restriction endonuclease fragment from the host chromosomal DNA. This result indicates that lysogeny involves integration of the phage into the host chromosome. A spontaneous phiLC3 clear plaque mutant that was unable to give rise to lysogens was isolated.

Bacteriophages↗

The course of renal amyloidosis with uraemia.

The course of uraemia in 47 patients with renal amyloidosis has been studied. The median survival with a S-creatinine of 150 mumol/l was approximately 18 months, but 15% survived for more than 3 years. Deterioration arose often suddenly and was of unclear cause. Approximately 25% of the patients improved for a while and the reason for this temporary improvement is also unclear. The unsteady course during the uraemia period for amyloidosis patients makes prognosis calculations very much less accurate than for patients with cystic kidneys.

Amyloidosis↗

Cadmium concentration in human kidney biopsies.

This study reports the cadmium concentration and histopathology of kidney tissue from 29 patients with clinical findings that motivated a diagnostic percutaneous kidney biopsy and/or a history of possible exposure to cadmium. Cadmium was found in all specimens examined including those from controls. In the patients, the mean cadmium concentration was 12.9 (0.6-45.0) micrograms cadmium per g wet kidney tissue. The highest concentrations (30-45 micrograms/g) were found in three patients with morphological and clinical findings of tubulo-interstitial damage. Patients with signs of tubulo-interstitial disease had higher mean cadmium concentrations than those with glomerular changes, and patients with normal blood pressure had higher concentrations than those with diastolic hypertension. In a control group of 22 autopsies, the mean cadmium concentration was 8.7 (2.9-22.4) micrograms/g. The mean difference between the right and the left kidney was 2.3 (0.9-9.6) micrograms/g. Laboratory findings in patients with cadmium nephropathy were nonspecific. Thus, in patients with interstitial nephritis and cadmium exposure, a biopsy for the analysis of kidney cadmium concentration may be motivated. The combination of morphological and clinical findings of interstitial nephritis and a high concentration of cadmium in biopsied kidney tissue indicates cadmium nephropathy.

Adult↗

Exposure to welding fumes and chronic renal diseases, a negative case-referent study.

It was observed that some patients with glomerulonephritis or interstitial nephritis were welders. A hypothesis that welding fumes were an occupational hazard was put forward and initiated the following case-referent study. 143 cases were defined as living males, age 25 to 65 years, with renal disease which caused renal biopsy from 1976-1982. Three population-based referents for each case were selected from the national register of the total population matched by sex, age and community. Exposure was assessed by means of a questionnaire. Only 7% of the cases and 12% of the referents did not answer the questionnaire. There were no differences in exposure rates between cases and referents, even if exposure restrictions were applied. The power of the case-referent study was high.

Adult↗

Nonfamilial polycystic kidneys without enlargement.

7 middle-aged males with bilateral, polycystic, nonfamilial kidneys without enlargement are described. The histological examination revealed multiple cysts of varying sizes and changes such as in interstitial nephritis. 6 of the patients had hematuria and/or calculi in the urinary tract. The etiology of the cysts is not clear. The picture does not conform to that of congenital cystic kidney. The cysts might possibly be a final phenomenon in contracted kidneys, so-called acquired cystic disease, but it should be noted that in 4 of the 7 cases the cystic degeneration was demonstrated log before the uremia appeared. Another possibility is that the cystic transformation described here might be attributed to a specific type of interstitial nephritis.

Adolescent↗

Differentiation of B15 strains of Neisseria meningitidis by DNA restriction endonuclease fingerprinting.

The restriction endonuclease fingerprinting technique was applied to meningococcal DNA in an attempt to identify individual strains of Neisseria meningitidis B15 (serogroup B, serotype 15), which causes approximately 90% of cases of meningococcal disease in northern Norway. Thirty representative strains (10 each from asymptomatic pharyngeal carriers, patients with septicemia, and patients with meningitis) were investigated with the restriction endonucleases Hind III and Eco RI. The 10 carrier strains showed a remarkable heterogeneity of fingerprints that rendered each strain easily distinguishable from the others. The 10 strains from the blood and the 10 from the cerebrospinal fluid showed similar but not identical restriction patterns. The results obtained with the two endonucleases were in perfect agreement. Our data suggest that a large number of different B15 clones are present in the population of northern Norway, but that only one single clone causes invasive meningococcal disease.

Carrier State↗

Applications of restriction endonuclease fingerprinting of chromosomal DNA of Neisseria meningitidis.

Restriction endonucleases are bacterial enzymes that cleave DNA at specific sites. The resulting DNA fragments may be separated electrophoretically in gel to form specific restriction patterns. In the present study, the restriction endonuclease method was successfully adapted to the analysis of the chromosomal DNA of Neisseria meningitidis. The endonucleases HindIII and EcoRI provided optimal restriction patterns of ca. 50 well-separated lines. The pattern of each bacterial isolate was characteristic, stable, and reproducible. Despite some general similarity, the restriction patterns of the closely related B15 meningococci were surprisingly heterogeneous.

Carrier State↗