Search PubMed⌕ Search

Biomedical subjects

M Lewis

Publications and source records attributed to M Lewis.

At least 361 records · Page 20Linked to original sources
PubMed1987

Low birth weight, prematurity, and postpartum endometritis. Association with prenatal cervical Mycoplasma hominis and Chlamydia trachomatis infections.

We studied associations of Mycoplasma hominis, Ureaplasma urealyticum, and Chlamydia trachomatis genital infections with pregnancy outcomes, controlling by logistic and multiple linear regression for known risk factors and for the presence of the other two infections. A sample of 1204 Navajo women enrolling for prenatal care had endocervical C trachomatis, M hominis, and U urealyticum cultures and serum samples taken at enrollment and when possible after 30 weeks. Low birth weight (less than 2500 g) was associated with M hominis infection among women with a history of spontaneous abortion. Mycoplasma hominis infection was also associated with postpartum endometritis, but only among women undergoing a cesarean section (odds ratio, 4.7; 95% confidence intervals, 1.22 to 18.3). Although women with recent C trachomatis infection (IgM titer greater than 1:32 on either sample or IgG seroconversion) were at greater risk of low birth weight (19% [3/16]) than women with chronic infection (4.5% [6/133]; relative risk, 4.2), this subgroup at risk was small (11% of women with classifiable C trachomatis infection). Mycoplasma hominis and C trachomatis infections may be important preventable causes of adverse pregnancy outcomes in identifiable subgroups of women.

Cervix Uteri↗
PubMed1987

Crystallographic analysis of the three-dimensional structure of baboon alpha-lactalbumin at low resolution. Homology with lysozyme.

The crystal structure of baboon alpha-lactalbumin has been determined at 6 A and at 4.5 A (0.6 nm and 0.45 nm) resolution by the method of isomorphous replacement. The principal derivative was prepared by reducing a disulphide bridge in the crystals and inserting a mercury atom. Detailed comparison of the electron-density maps with corresponding maps of hen egg-white lysozyme shows that they are closely similar, with correlation coefficients of 0.57 and 0.44 at 6 A and 4.5 A resolution respectively. This result, in accordance with earlier predictions based upon comparisons of amino-acid sequences, provides further evidence that class C lysozymes and alpha-lactalbumins are homologous proteins and it is in keeping with the hypothesis that the alpha-lactalbumins evolved from a lysozyme precursor.

Amino Acid Sequence↗
PubMed1987

Resistance to experimental autoimmune thyroiditis induced by physiologic manipulation of thyroglobulin level.

The role of circulatory mouse thyroglobulin (MTg) level in activating mechanisms suppressive to induction of experimental autoimmune thyroiditis (EAT) was studied by two regimens to strengthen normal maintenance of self-tolerance in genetically susceptible mice. One was to administer graded doses of exogenous MTg either 7 days apart or daily for 10 days and then challenge the animals with MTg + LPS. The other was to infuse TSH via an osmotic pump for 7 days. The steady TSH infusion for 7 days resulted in an increase in MTg level peaking on Day 3. Such kinetics of MTg concentration in response to TSH coincided with enhanced resistance to EAT induction. After an initial rapid clearance rate of t1/2 of 3 hr, tolerogenic doses of exogenous MTg sustained similar levels for 2-3 days. In contrast, subtolerogenic doses declined to baseline levels in 2 days or less. Clearance can be best explained by a two-compartment model for distribution with an initial alpha phase (t1/2 about 3 hr), followed by a beta phase (t1/2 about 10 hr). We conclude that, for the prevention of EAT induction in the presence of potent adjuvants (CFA or LPS), a threshold, but above baseline, level of either exogenous or endogenous MTg, represented by the beta phase, is required for a critical period (greater than 2-3 days) to activate suppressor mechanisms over and above homeostatic regulation. Whether MTg concentration raised by TSH (TRH) administration activates suppressor T cells as observed after the injection of a tolerogenic dose of MTg remains to be determined.

Animals↗
PubMed1987

Immunosuppression by canine distemper virus: modulation of in vitro immunoglobulin synthesis, interleukin release and prostaglandin E2 production.

In vitro or in vivo infection of canine mononuclear cells by canine distemper virus (CDV) in short-term microcultures resulted in suppression of lectin-induced 3H-thymidine incorporation. This suppressive effect was also evident in pokeweed mitogen-driven in vitro immunoglobulin synthesis and release. Lectin-induced interleukin-2 production by monocyte-depleted lymphocyte cultures was marginally affected by CDV, whereas interleukin-1 production by adherent mononuclear cells was significantly depressed. Monocyte cultures established from viremic dogs released prostaglandin (PG)E2. The results suggest that, in addition to a direct viral effect upon lectin responsive cellular population(s), CDV modulates monocyte functions by inhibition of interleukin-1 production and by enhancing PGE2 release.

Animals↗
PubMed1987

Infantile hypophosphatasia--linkage with the RH locus.

Linkage analysis of six nuclear families with infantile hypophosphatasia which were informative for the Rh blood group locus was performed. The maximum combined lod score was 4.76 with the recombinant distance (theta) of 0.04. These preliminary data provide evidence for linkage between the genes for infantile hypophosphatasia and the Rh blood group and provisionally assign the gene locus for infantile hypophosphatasia (designated HOPS) to chromosome 1p.

Adult↗
PubMed1987

Can one risk fasting the obstetric patient for less than 4 hours?

Forty patients scheduled for elective Caesarean section under general anaesthesia were divided into two groups. A control group of 20 patients was treated conventionally, whereas the other group was offered a light breakfast of tea and toast within 4 h of surgery. The volume of gastric contents was significantly greater (P less than or equal to 0.02) and the pH of the aspirate significantly lower (P less than or equal to 0.05) in the study group than in the control group. It is, therefore, not recommended that obstetric patients be fasted for less than 4 h.

Anesthesia, General↗
PubMed1987

Prolactin response to low dose sulpiride.

1 Prolactin levels in response to sulpiride were studied in healthy volunteers. 2 Oral doses of 1 mg-50 mg sulpiride or placebo were given. 3 A 3 mg sulpiride dose produced similar levels to those achieved with both 10 mg and 50 mg. 4 Circadian effects were studied showing no significant differences in the prolactin response to sulpiride. 5 Acute or chronic responses showed an attenuation with chronic sulpiride treatment to 50% of the peak levels attained with acute treatment. 6 These results indicate that sulpiride retains its potent ability to produce prolactin release even at the low doses studied here.

Adolescent↗
PubMed1987

Swa: a subdivision.

For some time, anomalous serological reactions have been observed when the same anti-Swa sera are tested against red cells from different individuals reported as Sw(a+). A comparative collaborative study using the same collection of Sw(a+) cells and anti-Swa sera was undertaken by 4 reference laboratories, and it was found that Swa represents a heterogeneous group of antigens that can be subdivided into two categories. Both categories, Sw(a+) 700:41 and Sw(a+) 700:-41, were shown to be inherited.

Blood Group Antigens↗
PubMed1987

The Yt blood group system (ISBT No. 011). Genetic studies.

Allele frequencies of Yta (YT1) and Ytb (YT2) in a series of 659 random Canadian Caucasians are comparable to those in European populations: 0.9469 and 0.0531, respectively. Inheritance of Yt phenotypes in 1,077 children in 286 selected families are in accordance with expectation on the basis of Mendelian codominance. Linkage studies exclude YT from chromosomal segments 1p36-1p22.1, 4q13-4q28, the section of chromosome 9 bounded by AB0 and AK1 and from the chromosome 19 linkage group bounded by LE and SE. Evidence is presented for a possible location of YT on the short arm of chromosome 6 distal to F13A.

Blood Group Antigens↗
PubMed1987

The LW:C3 recombination fraction in female meioses.

No recombinants between LW and C3, using a C3 DNA probe, were observed in 16 female meioses: z 4.216 at theta = 0.00. Combined with the data of Sistonen (1984) the recombination fraction between LW and C3 is estimated to be 0.09 (z 3.773) in females.

Antigens↗
PubMed1987

Population study of electrophoretic polymorphisms of red cell enzymes and plasma proteins in Caucasian Canadians.

Blood samples from a random series of Canadian Caucasians were phenotyped for 28 red cell enzyme systems and eight plasma protein systems. Polymorphism was found in 17 and rare variants in 11 of the systems. Allele frequencies are presented for these; distribution of phenotypes is in accordance with the Hardy--Weinberg equilibrium theory. In a complementary study of families there was no evidence of de novo mutation in any of the 36 systems and they allowed a minimum estimate of the frequency of null alleles in the ADA, C2, and GPT systems.

Alleles↗
PubMed1987

The sequence of chromosome 3 loci AHSG:TF:CHE1.

A large Hutterite kindred was examined for possible linkage between the chromosome 3 markers; cholinesterase (CHE1), transferrin (TF), and alpha-2HS glycoprotein (AHSG). Linkage between TF and AHSG was suggested in males (z = 1.515, theta = 0.08) and between CHE1 and TF(z = 0.661, theta = 0.21). However, linkage between CHE1 and AHSG in males was not established. Based on lods and a nuclear family informative for all three loci a possible chromosomal alignment for the loci is presented.

Cholinesterases↗