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Biomedical subjects

R M Schmidt

Publications and source records attributed to R M Schmidt.

At least 73 records · Page 4Linked to original sources
PubMed1977

The state and territorial public health laboratory: program activities, organization and prospects for the future.

During the past two years we have studied the characteristics of state and territorial public health laboratories in an attempt to develop guidelines for considering reorganization of laboratory services in Massachusetts. Only a few recent monographs have dealt with this topic and, to our knowledge, the functional and organizational characteristics of these laboratories have not been reviewed. The state public health laboratory system affords an excellent example of applied laboratory science or technology organized to provide basic public health services. In this paper the programs and organization of the state public health laboratory are reviewed, and a functional basis more responsive to society's current needs is suggested.

Economics, Medical↗
PubMed1977

Hemoglobin Lufkin: beta 29 (B11) Gly replaced by Asp. An unstable hemoglobin variant involving an internal amino acid residue.

Hemoglobin Lufkin was found in a Black-American family. Structural analysis of the abnormal hemoglobin indicates a substitution of aspartic acid for glycine at position 29 in the beta chain. Marked instability of the variant hemoglobin is demonstrated by the rapid formation of inclusion bodies upon exposure of the red cells to redox dyes and by the large percentage of precipitated hemoglobin at 65 degrees C. The oxygen affinity, the Bohr effect, and the degree of cooperativity of Hb Lufkin and Hb A are similar over the physiologic pH range. However, at acid pH the oxygen affinity of the variant is increased. Unlike several other reported variants in the B helix, Hb Lufkin is not associated with methemoglobinemia.

Amino Acids↗
PubMed1977

[Electroencephalographic curves in diseases of the basomedian cerebral structures].

In twenty-two patients bilaterosymmetric, slow frequencies occurring in groups frontoprecentrally and frontoparietally, respectively, were found for a total of thirty-four spaceoccupying processes of basomedian structures. Such alterations should not be considered to be characteristic of tumors located adjacent to the median line, but may be regarded as an important indication. The changes themselves are due to the diffuse thalamocortical system as well as the reticular activating system. The overlapping of functions of these systems and the different responses of equal structures to different intensities of stimulation make it impossible for clinicians to assign them to individual basomedian structural levels even if necropsy records and reports on surgical operations are taken into consideration.

Brain Edema↗
PubMed1976

Hemoglobin Fannin-Lubbock [alpha2 beta 2 119 (GH2) Gly replaced by Asp]. A new hemoglobin variant at the alpha1 beta 1 contact.

Hemoglobin Fannin-Lubbock was found in a 9-year-old Mexican-American female. The abnormal hemoglobin was detected as a fast-moving variant by electrophoresis on cellulose acetate at pH 8.4. Structural analysis indicated a substitution in the beta-chain of aspartic acid for glycine at position 119, a position involved in the alpha1beta1 contact of the hemoglobin tetramer. This contact between unlike chains is larger and undergoes a smaller shift during the process of oxygenation and deoxygenation that the alpha1beta2 contact (Perutz, M.F., Muirhead, H., Cox, J.M. and Goaman, L.C.G. (1968) Nature 219, 131-139). Mutations in this contact tend to cause slight or no changes in functional behavior. Apart from a mild anemia, the propositus did not exhibit any obvious clinical symptoms.

Amino Acids↗
PubMed1976

Hemoglobin Providence. A human hemoglobin variant occurring in two forms in vivo.

Hemoglobin Providence Asn and Hemoglobin Providence Asp are two abnormal hemoglobins which apparently arise from a single genetic change that substitutes asparagine for lysine at position 82 (EF6) in the beta chain of human hemoglobin. The second form appears to be thr result of a partial in vivo deamidation of the asparagine situated at position beta 82. Cellulose acetate and citrate agar electrophoresis of hemolysates from patients with this abnormality shows three bands. Globin chain electrophoresis at acid and alkaline pH shows three beta chains. These three chains correspond to the normal beta A chain and two abnormal beta chains. Sequence analysis indicates that the two abnormal chains differ from beta A at only position beta 82. In the two abnormal chains, the residue which is normally lysine is substituted either by asparagine or by aspartic acid. These substitutions are notable because beta 82 lysine is one of the residues involved in 2,3-diphosphoglycerate binding. Additionally, beta 82 lysine is typically invariant in hemoglobin beta chain sequences. Sequence data on the two forms of Hemoglobin Providence are given in this paper. The functional properties of these two forms are described in the next paper.

Adult↗
PubMed1976

Hemoglobin Bethesda, beta 145 (HC2) Tyr replaced by His, in a Canadian family.

A hemoglobin mutant with the mobility of hemoglobin (Hb) A on alkaline cellulose acetate or starch gel electrophoresis and mobility between Hb A and Hb S on citrate agar electrophoresis was detected in a patient with erythrocytosis. Structural analysis shows a substitution of histidine by tyrosine at position 145 in the beta-chain.

Adult↗
PubMed1976

Hemoglobin Jackson, alpha 127 (H10) Lys replaced by Asn.

A new hemoglobin mutant was detected as a fast-moving variant on cellulose acetate electrophoresis at pH 8.4. The mutation is in the alpha-chain at position 127, where lysine is substituted by asparagine. This is an external residue, and mutation at this site does not lead to any altered physiologic function of the hemoglobin.

Adult↗
PubMed1976

Effects of hemoglobin F levels, KCN, and storage on the isopropanol precipitation test for unstable hemoglobins.

Although the isopropanol precipitation test is a commonly used and sensitive test for detecting unstable hemoglobins, false-positive reactions are frequently observed. In this study, the storage temperature of the test samples, type of stored sample amount of fetal hemoglobin (Hb F) in the sample, and presence of potassium cyanide (KCN) in the hemolysate preparation all affected the accuracy of the test. The addition of 2% KCN to samples before testing eliminated or greatly reduced false-positive reactions. Hb F levels greater than 4% caused false-positive results. When specimens with Hb F levels less than 4% were stored at 4C and as whole blood, they showed no false-positive reaction for as long as two weeks. However, duplicate specimens stored as whole blood but unrefrigerated and those stored as hemolysates showed false-positive reactions after three days.

1-Propanol↗
PubMed1976

Use of blood specimens collected on filter paper in screening for abnormal hemoglobins.

Both cellulose acetate electrophoresis and citrate agar electrophoresis were performed on 834 blood samples collected on filter paper in Jamaica and shipped for testing to the National Hemoglobinopathy Standardization Laboratory at the U.S. National Center for Disease Control. Additionally, 30 blood samples collected locally were stored on filter paper, in microhematocrit capillary tubes, and as whole blood specimens; at selected times the samples were tested for stability to determine the best sample-collection technique for hemoglobin electrophoresis. Results were most nearly accurate when both cellulose acetate electrophoresis and citrate agar testing were used. The methods are easy to perform, but results are unreliable if the blood samples on filter paper are stored at 4 degrees C for longer than two weeks before they are tested.

Agar↗
PubMed1976

Immuneglobulin investigations in inflammatory diseases.

1. The agar electrophoresis of the cerebrospinal fluid and the quantitative immune globulin determination contribute essentially to an assessment of the immunity state in inflammatory diseases of the CNS. 2. It is necessary to distinguish protein augmentation due to brain-barrier disturbances (accompanying proteinosis of the cerebrospinal fluid), which we find in metabolic and traumatic diseases, from a genuine increase in cerebrospinal fluid protein. 3. Autochthonous formation of cerebrospinal fluid protein can be demonstrated by means of quantitative IgG, IgA and gamma3-globulin determination.

Blood-Brain Barrier↗