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Biomedical subjects

B Larsen

Publications and source records attributed to B Larsen.

At least 163 records · Page 9Linked to original sources

Linkage analysis of loci controlling blood groups and the rectovaginal constriction syndrome in Jersey cattle.

The possibility of linkage between the recessive gene controlling the rectovaginal constriction (RVC) syndrome in Jersey cattle and 13 loci controlling blood groups and polymorphic proteins was studied. No evidence of close to moderate linkage was found between the RVC locus and any of the systems A, B, C, F, L, S, Z, R', Hb, Tf, Am-1 and Ca. No definite conclusion was possible with the M system.

Animals↗

Pharmacokinetics of cefotaxime, moxalactam, and cefoperazone in the early puerperium.

Twelve parturient women volunteered to receive 1 g of cefotaxime on the second or third day postpartum by intravenous infusion over 3 min. Blood was taken from the antecubital vein of the contralateral arm at 0.25, 0.5, 0.75, 1, 2, 4, and 6 h. The concentration of cefotaxime in serum was assayed by agar diffusion, with Sarcina lutea ATCC 9341 as the indicator strain. The same 12 women received an identical dose of antibiotic 4 months after the first dose, and blood was taken at the same time intervals as in the first study to measure antibiotic levels. An additional 24 women participated in identical studies with either moxalactam or cefoperazone. Cefoperazone afforded the highest concentration in serum of the three drugs, followed by moxalactam. These differences in the concentration in serum were seen both early postpartum and 4 months later. However, the concentration in serum of all three drugs was diminished 2 and 3 days postpartum compared with 4 months postpartum. Most pharmacokinetic parameters were also significantly altered early in the puerperium relative to those obtained 4 months later. The altered pharmacokinetic behavior of antibiotics associated with pregnancy appears to persist into the early puerperium.

Adult↗

Implications of metronidazole pharmacodynamics for therapy of trichomoniasis.

A liquid chromatographic technique for the detection of metronidazole (MDZ) and its major metabolites, combined with a vaginal sampling technique employing extraction of drug from vaginal swabs, was used to evaluate the concentration of MDZ in the vaginal fluid during therapy. Wide variation in the absolute concentration of unchanged drug was noted, although the average vaginal levels were about half the serum concentration 2 h after treatment had been initiated and comparable to the serum levels 6 and 24 h after treatment. Oral administration of MDZ invariably resulted in the presence of the drug in the serum and urine but the drug was not always detected in the vaginal secretions. The presence of the relatively inactive acetyl metabolite in the vaginal fluid of patients who failed to respond to therapy for trichomoniasis suggested the possible role of drug modification as a contributing factor in the lack of therapeutic success. The presence of MDZ in women in whom the cervix had previously been surgically removed attests to the transport or transudation of the drug across the vaginal epithelium without involvement of the secretory activity of the cervix.

Administration, Oral↗

Class III alleles and high-risk MHC haplotypes in type I diabetes mellitus, Graves' disease and Hashimoto's thyroiditis.

By typing a large quantity of family-based material for HLA-B, HLA-DR, C4, C2 and factor B, we were able to derive four-gene complement haplotypes (C4A, C4B, C2, BF) and six-gene MHC haplotypes (HLA-B, complement, HLA-DR). Fourteen six-gene MHC haplotypes showed linkage disequilibrium but exact frequencies could not be determined because it was not always possible to assign null C4 alleles in families where null genes were not clearly seen to segregate. Comparison of unrelated type I diabetes, Graves' disease and Hashimoto's thyroiditis patients with healthy unrelated controls revealed the following MHC allele associations: C4B*3, HLA-DR3 and HLA-DR4 with type I diabetes; BF*F1 and HLA-DR3 with Graves' disease; HLA-DR4 with Hashimoto's thyroiditis. By typing families of type I diabetes and Graves' disease patients we were able to derive two high-risk DR3+ MHC haplotypes for both type I diabetes and Graves' disease. These are HLA-B8 C4A*Q0 C4B*1 BF*S HLA-DR3 and HLA-B18 C4A*3 C4B*Q0 BF*F1 HLA-DR3, and these haplotypes account for most of the associations between these diseases and HLA-DR3. The MHC haplotype HLA-B15 C4A*3 C4B*3 BF*S HLA-DR4 also carries high risk for type I diabetes in this group of patients. Our data suggest that other DR4+ haplotypes, probably containing C4A*3 C4B*1, carry increased risk for type I diabetes whereas haplotypes containing DR4 and C4 C4A*3 C4B*Q0 do not. Our phenotype data suggest that DR4 in Hashimoto's thyroiditis is frequently associated with HLA-B44, C4A*3, C4B*1 and BF*S.

Alleles↗

Lack of association of HLA with thyroid cancer. An effect of iodine sufficiency and safe environment?

We examined HLA association with differentiated thyroid carcinoma in 45 patients from Newfoundland. No association was found. This finding contrasts with the description of an association of thyroid cancer with HLA-DR1 in Italy and Hungary (iodide deficient areas) and with DR7 in the American mid-west. We suggest that iodide deficiency predisposes DR1 + individuals to thyroid cancer and that this risk is negated by iodide sufficiency unless some other risk factor supervenes.

Adenocarcinoma↗

A new technique to register proliferation of clonogenic cells from brain tumors.

The soft agar technique for culturing human clonogenic tumor cells has been usefully applied for predicting individual clinical responses to chemotherapy, for screening of new antineoplastic drugs, and in basic biological research. The counting of colonies formed by clonogenic cells is, however, a rather time consuming and inaccurate procedure. We here report a method to combine the easy and precise registration of DNA-synthesis by 3H-thymidine incorporation with the ability of soft agar to permit proliferation of clonogenic cells and inhibit proliferation of non-neoplastic cells. The glioma cell lines U 251 MG and T-MG 1, the benignant glia cells T-BG 1, T-BG 2, T-BG 3 and fibroblasts were cultured in Furcellaran gel. Twenty hours before harvesting 3H-thymidine was added. The Furcellaran gel was resolved by 50 mM LiI. The cells were trapped on glass fiber filters and incorporated radioactivity was measured. 3H-thymidine incorporation in malignant cells increased exponentially with time, while 3H-thymidine incorporation in the benignant glia cells and fibroblasts was inhibited. The correlation between number of colonies counted after 16 days and 3H-thymidine incorporation registered after different culture times was very good. The correlation was best when the cultures were harvested after 8 days (r = 0.95), indicating that it is possible to reduce the assay time. The five glioma biopsies tested grew well with a mean plating efficiency of 0.4% (range 0.02-1.8%). The most intense proliferation seemed to take place during the first week in culture. The good correlation between 3H-thymidine incorporation on day 7 and colony number on day 14 (r = 0.93), indicate that reduction of assay time is possible also for the glioma biopsies.

Agar↗

C4B3 allotype with a novel Ch phenotype.

The fourth component of complement (C4) has two classes of protein, C4A and C4B, both of which have many allelic forms. The serological determinants Rodgers (Rg1, Rg2) and Chido (Ch1, Ch2, Ch3) are generally associated with C4A and C4B, respectively. The C4B3 allotype has been detected in a single Canadian family that expresses a novel Ch phenotype, Ch:-1, 2, -3. There was no information for the Rg determinants, as the C4A*2B*3 haplotype would normally express Rg on the C4A protein. Other C4B3 allotypes in informative families have different Ch phenotypes, and the relationships of these within extended major histocompatibility complex haplotypes are discussed in this paper.

Alleles↗

Association of the M blood group system with bovine mastitis.

Associations of the 11 bovine blood group systems with mastitis were examined in Red Danish dairy cattle. The mastitis status was followed during three lactational periods. A significant effect of the M blood group system on mastitis incidence was observed in the first and second lactation periods and a lower frequency of mastitis is found among animals lacking the M' factor as compared to those having the M' blood group factor. The significance of these results are discussed in view of the close relation between the M blood group system and the bovine lymphocyte antigens (BoLA), and the expected effect of eliminating the M' gene from the breed is estimated. Among the remaining 10 blood group systems, the T' system was the only system showing an overall effect on mastitis, and only in first and third lactation. However, the T' system was inconsistent with regard to the effect of the T' gene on the various mastitis diagnoses.

Animals↗

Pharmacokinetics of piperacillin in the postpartum patient.

Six women were given 1 g of piperacillin on the 2nd postpartum day and serum concentrations of the drug were measured at 0.5, 1, 2, and 4 h after infusion. The same women returned for an identical test 6 months later and hence served as their own controls. A second group of 6 women were treated identically except that they received the first dose of piperacillin on the 3rd postpartum day. The serum levels of antibiotic were consistently lower during the puerperium than at 6 months. The levels obtained at 2 compared to 3 days post partum were similar, but were about one half the levels obtained at 6 months post partum. These results indicate that antibiotic therapy for postpartum endomyometritis may need to take account of the fact that the altered pharmacokinetics of pregnancy persists into the puerperium. If used in this setting, the dose of piperacillin may need to be increased by 50% over the normal adult dose.

Adult↗

Polymorphism of the fourth component of complement in Graves' disease and type I diabetes mellitus.

The distribution of major histocompatibility complex (MHC) phenotypes in unrelated patients with Graves' disease or Type I diabetes mellitus and healthy controls was examined. HLA-B8 was increased in both the Graves' disease patients (p = .0018) and diabetes mellitus patients (p = .0246) relative to controls. Although C4A*QO is known to show strong linkage disequilibrium with HLA-B8, we could not demonstrate a difference in the frequency of this allele between either group of patients and the controls because the null C4A*QO cannot be accurately estimated from phenotype data. An unusual variant C4B*3 occurred three times in 117 controls, 10 times in 61 Graves' disease patients (p = .0012) and 13 times in 48 diabetic patients (p = 0.74 X 10(-5]. Although C4B*3 is known to show strong linkage disequilibrium with HLA-B15, the frequencies of B15 in the two patient groups did not differ from that of the controls considered here. When 28 MHC haplotypes (supratypes) from 14 unrelated patients with Type I diabetes were compared with 27 non-diabetes supratypes occurring in the same families but not in the patients, 8/28 Type I diabetes supratypes were C4AQOB1+, HLA-B8+, and 4/28 were C4B*3+, whereas 1/27 non-diabetes supratypes was C4AQOB1+, B8+, and 0/27 was C4B*3+. Of the four C4B*3+ diabetes positive supratypes, two were HLA-B15, one was B5 and one was B40. Finally, the second haplotype of 11 diabetes mellitus patients known to carry one high risk C4 haplotype was investigated. The second haplotype was the common type C4A3B1 in only 3/11, whereas at least 5/11 had second haplotypes containing C4B*QO, C4B*3, C4B*2 or C4A*4.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗

Problems in specimen collection for sexually transmitted diseases.

Laboratory methods for the diagnosis of sexually transmitted diseases (STDs) are continuously undergoing improvement. It remains the responsibility of the clinician to become familiar with the tests available for the diagnosis of STDs. Those tests depend on obtaining clinical specimens from the proper site and on transporting them to the laboratory under satisfactory conditions.

Bacteriological Techniques↗