Search PubMed⌕ Search

Biomedical subjects

R Schmidt

Publications and source records attributed to R Schmidt.

At least 703 records · Page 39Linked to original sources
PubMed1981

Dermatoglyphic and cytogenetic studies in parents of children with trisomy 21.

Dermatoglyphic studies were carried out of 131 mothers and 95 fathers of children with Down syndrome and 200 controls (100 males and 100 females) using the Hopkins single score method. Twelve percent of the mothers and 2% of the fathers showed dermatoglyphic abnormalities including a distal axial triradius (t"), hypothenar ulnar loops, radial loops on digits IV and V and abnormal palmar creases, resulting in a positive Hopkins score or a score in the "overlapping range" (greater than -3). The origin of the extra chromosome could be determined in 23 of a total group of 40 families. In 22 of the former, the mother was the donor of the extra chromosome; in one it was the father, In these 23 families, a Hopkins score in the overlapping range was found in three mothers who were all under the age of 35 years at the birth of the affected child. Since cytogenetic studies cannot easily differentiate between meiotic nondisjunction and mosaicism as a basis for 21 trisomy in the progeny, it is possible that mothers with positive overlapping Hopkins scores represent undetected mosaics for a trisomic cell line. The dual approach utilizing dermatoglyphic and cytogenetic studies may aid in identifying persons with an enhanced risk for having children with Down syndrome.

Adult↗
PubMed1981

Effect of blood donations on the profile of lymphocytic cells.

The effect of ordinary blood donation and repeat leukapheresis procedures on the profile of lymphocytic cells in peripheral blood was assessed. In ordinary blood donors blood donation was found to have no effect on serum Ig levels and peripheral lymphocyte populations. The removal of leukocytes and serum Ig during leukapheresis lead to a significant decrease of serum IgG and IgM and of all lymphocytic cell parameters, O cells being the only exception. During a series of 5 consecutive cytaphereses serum Ig always reached prepheresis levels within a week. With the increasing number of leukaphereses, however, lymphocytic cells, except O cells, showed a steady decrease which was significant for B cells bearing surface IgA, G, M or lambda chains. Even 2 months after the last leukapheresis mononuclear cell numbers had not returned to first prepheresis levels. a limitation of leukapheresis procedures per annum is recommended.

Adult↗
PubMed1981

A radioimmunoassay for ependymins beta and gamma: two goldfish brain proteins involved in behavioral plasticity.

A radioimmunoassay (RIA) using 125I-labeled antigen was developed for the quantitative determination of two goldfish brain proteins (ependymins beta and gamma). The proteins were isolated from the cerebrospinal fluid (CSF) and cells of the ependymal zone surrounding goldfish brain ventricles. The turnover rates of beta and gamma were previously shown to be specifically enhanced after the animals successfully acquired a new pattern of swimming behavior. Femtomole quantities of ependymin beta were measurable by the RIA. In applications of the assay, beta and gamma ependymins were found to have common immunological properties, since 125I-beta-antigen bound to antibody could be displaced by unlabeled ependymin gamma as well as ependymin beta but not by a variety of other proteins including several purified glycoproteins isolated from goldfish brain. The ependymins were shown to constitute 14% of the total protein content of the brain extracellular fluid and also to be present as a minor component of the serum proteins (0.3%). Ependymins beta and gamma have an immunological reactivity in these fractions that can be increased by a factor of 30 on heating. The data suggest that the antigenicity of the molecules is highly masked, and that it may require some unraveling of the quaternary structure of the proteins before maximal interaction with the antisera becomes possible.

Animals↗
PubMed1981

Immediate and delayed onset "skip area" dermatitis presumed secondary to topical phenol exposure.

A 21-year-old man was in brief accidental skin contact with epoxy resin stripper containing 10% phenol. He developed a painful, superficial necrotic eruption which slowly extended proximally without any further contact with the chemical, leaving skip areas of normal skin. About 3 and 7 months later he reported spontaneous flares within the area of original contact. Gradual release from an initially formed phenol-protein complex is thought to be responsible for the progression beyond the contact area and the delayed reaction.

Administration, Topical↗
PubMed1981

the effects of termination of pregnancy: a follow-up study of psychiatric referrals.

A series of 57 women presenting in the first years of the implementation of the Abortion Act for a psychiatric opinion on termination of pregnancy (TP) were carefully examined. The average scores on psychometric tests were well into the pathological range. Of the 25 recommended for TP 24 were single, 20 had been separated from one or both parents and 6 had a psychiatric history. On those women available for follow-up the mean psychometric scores improved early (1-17 months after consultation) and eventually fell to the normal range (3-6 years after consultation). A particular feature of the study wa an in-depth follow-up fo the subsample of 10 women. This was especially illuminating on the meaning that the pregnancy had for the patient. Ambivalent feelings towards the pregnancy were recalled. Some had used the pregnancy to hold on to the father. Many were still acting out problems with the family of origin. Their relationships with the medical profession were often unsatisfactory. The study increases our (still patchy) understanding of this population and confirms the need for counselling at the time that the woman first presents, both to avoid adverse psychiatric sequelae and to use the abortion as a critical experience to improve overall adjustment.

Abortion, Induced↗
PubMed1981

Ring chromosome 14: a distinct clinical entity.

An infant girl with ring chromosome 14 is presented. The findings in this patient and in six previously reported cases of a ring 14 suggest that a characteristic clinical syndrome is associated with this chromosome aberration. The major features of the ring chromosome 14 syndrome include mental retardation, a disorder of skin pigmentation, seizures, and dysmorphic features, including flat occiput, epicanthal folds, downward slanting eyes, flat nasal bridge, upturned nostrils, short neck, and large low set ears.

Abnormalities, Multiple↗
PubMed1981

Myelin sheath maturation of intrapulmonary axon bundles in the rabbit fetus.

The development of intrapulmonary myelin sheaths began in the central parts of the lung and proceeded towards the periphery. It started suddenly on the 25th post conceptional (p.c.) day. Early stages of myelination could be demonstrated in the periphery on the 27th day p.c (2) Axons not surrounded by Schwann cells could be seen in large numbers on the 24th and 25th day p.c. but they became fewer on the following days. (3) Myelinated axons was found were often at the periphery of the axon bundle. The maximum number of myelin layers was 7 on the 25th day p.c. and 30 on the 31st day p.c. (4) Axons at early stages of myelination were seen along with axons with more progressive myelin sheath development. Abnormal structures of myelinated fibers could be demonstrated. Their significance is discussed.

Animals↗
PubMed1981

[Functional and structural behavior of the cardiovascular system of normotonic and spontaneously hypertensive rats following chemical sympathectomy and angiotensin administration].

The non-cleared influences of the sympathetic nervous system [sN] on structural reactions of SHR and on the direct cardiac effects of AII and the structural vascular behavior were investigated. In 67 spontaneously hypertensive rats (Okamoto-Aoki) and 55 normotonic Wistar rats (NR) the blood pressure behaviour, the structural vascular and organ reactions and the noradrenaline (NA) content of the myocardium were examined with an intact sympathetic nervous system as well as after its almost complete elimination by chemical sympathectomy with 6-hydroxy-dopamine (6-OH-DA). Moreover, the functional and structural responsiveness of the arterial vessels of sympathectomized animals to angiotensin II administrations was investigated. 6-OH-DA in the dosage applied, induces during its time of action in NR a smaller, in SHR a larger decrease of blood pressure and, presumably induced by intense NA-depletion of the myocardium, myocardial alterations. Despite extensive AII-induced alterations of the already early hypertrophically-hyperplastically changed vascular wall, the structural and functional responsiveness of the arterial vascular system was maintained even after sympathectomy, and the sensitivity of the SHR to AII remained. For maintaining hypertension, the cooperation of structural and functional influences is necessary, as is indicated by the reduction of blood pressure in sympathectomized SHR and its regular return to the daily initial values of normotonic animals under additional AII administration. Besides the vascular alterations contributing to the exacerbation of the hypertension, here the sNS is of essential importance. For obtaining a total pressure effect of AII the sNS obviously has not necessarily to be intact, though its activity state can influence the responsiveness of the arterial vascular system to AII. The reduction of the sympathicotonus by sympathectomy seems to have a protective effect on the development of AII-induced structural vascular alterations; in contrast to the myocardium in SHR, in which it induces an exacerbation and an increase in the AII-induced myocardial alteration. These findings obtained from rats are supposed to be important also for the essential hypertension in man. By maintaining the functional responsiveness of the arterial vascular system, antihypertensives which react with the different parts of the sNS cab become effective while structural alterations of the vascular wall can be influenced, too. The possibility of the simultaneous development of myocardial alterations should be taken into special consideration.

Angiotensin II↗
PubMed1981

The role of volume depletion, antidiuretic hormone and angiotensin II in the furosemide-induced decrease in mesenteric conductance in the dog.

Furosemide caused a significant reduction in mesenteric blood flow and conductance as early as 10 min after administration. When fluid losses were not replaced, conductance continued to decline. In volume-repleted animals, conductance fell initially but failed to decrease further. Thus, furosemide decreases mesenteric conductance in two ways: a small early decrease which is not related to volume loss and a later more marked decrease which is related to volume loss. The initial decrease in conductance seen in furosemide-treated animals appears to be mediated via the renin-angiotensin system. In volume-repleted as well as volume-depleted animals, the plasma concentrations of renin and angiotensin II, but not antidiuretic hormone, were increased 10 min after furosemide administration. Also, inhibitors of the renin-angiotensin system abolished the response. The later decrease in mesenteric conductance induced by furosemide is more complex. When fluid losses were not replaced, plasma levels of angiotensin II and renin, as well as antidiuretic hormone, were increased 40 min after furosemide administration. Neither an infusion of Sar1-Ile8-angiotensin II nor hypophysectomy, alone, prevented the furosemide-induced decrease in conductance. The decrease in conductance was reversed when Sar1-Ile8-angiotensin II was infused into hypophysectomized dogs. Thus, the later more marked decrease in conductance induced by furosemide is related to three factors: volume loss, plasma concentration of angiotensin II and plasma concentration of antidiuretic hormone. Mesenteric conductance is decreased by furosemide if plasma concentrations of one or both vasoactive factor are elevated in the presence of a decrease in extracellular volume.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1981

Alloimmunization against the MHC antigens after platelet transfusions is due to contaminating leukocytes in the platelet suspension.

Repeated platelet transfusion to thrombocytopenic patients frequently induce anti HLA antibodies, which are responsible for transfusion refractoriness. As the transfused platelet suspensions usually contain 15-30% of the leukocytes originally present in the blood, it is not known whether these antibodies are raised by the platelets or by the contaminating leukocytes in the platelet suspensions. In the mouse, pure platelet suspensions are not able to induce a primary antibody response, as measured by the NIH test and the indirect immunofluorescence test on platelets and leukocytes, despite repeated injections. However, when the platelet suspensions are contaminated with leukocytes (10(3) or more/injection) an antibody response is induced. This response is higher than the response indiced by an equal amount of leukocytes alone. As in man the use of leukocyte poor platelets postpones the development of refractoriness to random platelets it is concluded that transfusions with leukocyte free platelets will probably prevent immunization against the HLA antigens.

Animals↗
PubMed1981

[Functional and structural reactivity of the arterial vascular system to angiotensin II in spontaneously hypertensive rats].

In 55 spontaneously hypertensive rats (SHR) (Okamoto/Aoki) and 63 normotensive Wistar rats (NR) receiving Angiotensin-II, hypertrophically-hyperplastically altered vessels of SHR were tested for their functional and structural reactivity and compared with the behaviour of the arterial vascular system at essential hypertension of man. After 5 days of treatment with 0.15 and 0.02 mg depot-Angiotensin II (A-II) SHR showed an increase in systolic and, with 0.15 mg A-II, even in diastolic blood pressure and bradycardia. At either A-II dosage, plasmatic vasculoses were found at the arterioles and small arteries both in SHR and similarly treated NR, though in higher frequency and in a larger quantity in SHR, as it was the case also with myocardial alterations. Although in the arterial vessels in SHR there developed already primary hypertrophically-hyperplastic wall alterations, A-II application led to functional and structural reactions. Consequently, an additional vasoconstrictor stimulus does not lead in SHR to a process comparable with essential hypertension in man, but merely to reversible, acute vasculopathies.

Angiotensin II↗
PubMed1981

[Isoelectric behavior of oxyhemoglobin].

This paper presents changes of the isoelectric behaviour of hemoglobin depending on the ionic strength and the buffer system. With increasing ionic strength the isoelectric point of oxy-hemoglobin changes to lower pH-values. The isoelectric function of oxy-hemoglobin is different in various buffer systems.

Buffers↗
PubMed1981

[Polarization optical investigations for the demonstration of a "sialomucin coat" at the surface of the chorionic epithelium of the rabbit placenta in relation to the stage of pregnancy].

Histological, histochemical, fluorescence optical and polarization microscopical investigations were performed in 53 placentas of rabbits from the 10th to the 35th day of pregnancy. A "sialomucin coat" could be demonstrated in all cases at the maternal surface of the metabolic barrier of the placenta. Polarization optical measurements after association with N,N'-diethylpseudoisocyanine chloride showed a lower content of sialic acid at the surface of the trophoblast in postmature placentas of rabbits in comparison to normal mature placentas. The immunological function of the placental barrier is discussed with respect to maturity.

Animals↗
PubMed1980

[Technics and indications for hemofiltration treatment].

Technique, possibilities of application, advantages and disadvantages of haemofiltration are described. A convective mass transport underlies the method. By this means the elimination of molecules of different size takes place with the same speed and the removal of so-called middle molecules is performed more effectively than in the usual method of dialysis.

Acute Kidney Injury↗