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Biomedical subjects

P Lundström

Publications and source records attributed to P Lundström.

14 recordsLinked to original sources
PubMed2001

Proliferation of primitive myeloid progenitors can be reversibly induced by HOXA10.

Recent studies show that several Hox transcription factors are important for regulation of proliferation and differentiation in hematopoiesis. Among these is H0XA10, which is selectively expressed at high levels in the most primitive subpopulation of human CD34(+) bone marrow cells. When overexpressed, H0XA10 increases the proliferation of early progenitor cells and can lead to the development of myeloid leukemia. To study the effects of H0XA10 on primitive hematopoietic progenitors in more detail, transgenic mice were generated with regulatable H0XA10 expression. The transgenic mouse model, referred to as tetO-HOXA10, contains the H0XA10 gene controlled by a tetracycline-responsive element and a minimal promoter. Thus, the expression of H0XA10 is inducible and reversible depending on the absence or presence of tetracycline or its analog, doxycycline. A retroviral vector containing the tetracycline transactivator gene (tTA) was used to induce expression of the H0XA10 gene in bone marrow cells from the transgenic mice. Reverse transcription-polymerase chain reaction analysis confirmed regulatable H0XA10 expression in several transgenic lines. H0XA10 induction led to the formation of hematopoietic colonies containing blastlike cells and megakaryocytes. Moreover, the induction of H0XA10 resulted in significant proliferative advantage of primitive hematopoietic progenitors (spleen colony-forming units [CFU-S(12)]), which was reversible on withdrawal of induction. Activation of H0XA10 expression in tet0-H0XA10 mice will therefore govern proliferation of primitive myeloid progenitors in a regulated fashion. This novel animal model can be used to identify the target genes of HOXA10 and better clarify the specific role of HOXA10 in normal and malignant hematopoiesis.

Animals↗
PubMed1985

Oral contraceptives and the cobalamin (vitamin B12) metabolism.

The mean concentrations of serum (S)-cobalamin (vitamin B12) and S-unsaturated B12 binding capacity (UBBC) were significantly decreased in 101 women (mean age: 30.4 years) taking oral contraceptives (OC) of the combination type, compared to 113 controls. OC users more frequently showed decreased concentrations of S-cobalamin (less than 200 pmol/l) than did their controls. However, the incidence of particularly low concentrations (less than 150 pmol/l) in OC users was not increased. To study a possible dose-dependent effect, 27 women (mean age: 50.5 years) given high-dose estrogen preparations (1-4 mg estrogen) were compared with 31 controls. The two groups showed no difference with regard to S-cobalamin, but the mean S- and plasma-UBBC levels were significantly decreased in the high-dose estrogen group. 12 OC users with decreased S-cobalamin (less than 200 pmol/l), 9 OC users with normal S-cobalamin and 10 controls were studied more intensively. The mean hemoglobin concentration was significantly decreased in those OC users having decreased S-cobalamin. On the contrary, the absorption and excretion of radiolabeled cobalamin and the concentrations of erythrocyte-folate, S-iron and -transferrin did not show any difference between the groups, and all results were normal, by and large. No characteristic changes in plasma volume were found. It is concluded that routine measurement of S-cobalamin in women taking OC is not justified.

Adult↗
PubMed1977

Spontaneous rupture of the uterus in the third trimester with a living fetus expelled into the abdominal cavity.

A case of rupture of the uterus during pregnancy with the living fetus expelled intra-abdominally is reported. The main symptoms were slowly increasing abdominal colicky pains. During the first five days of the hospital stay the woman's condition deteriorated and a paralytic ileus developed. The fetal lie changed between the second and third day from longitudinal to transverse and the fetus became situated at the umbilical level. At the same time the fetal heart sounds could no longer be detected and the tense uterine wall grew soft. The changed fetal lie and the paralytic ileus were radiologically substantiated. In spite of a delayed diagnosis the child and the mother were both saved. The etiology was possibly damage to the fundal wall at an earlier curettage carried out because of a spontaneous abortion. The differential diagnosis is discussed from the obstetrical as well as from the radiological and other methodological points of view.

Adult↗
PubMed1975

[Therapeutic results of colposcopically controled collection of cervix tissue in atypical smears of women up to the age of 35 years].

The case series consists of 106 women consecutively collected during 1968 to 1973 from those with a vaginal smear belonging to Papanicolou's groups III and attending the gynaecological department in Umeå. Probably the series is a fair random sample of the population (congruent to 150,000 people) of the area served by the clinic. The extension of the colposcopically delimited atypical transformation zone (with its upper bordèrline against normal cervical villi) in most cases being small, the surgical procedure--a small cone congruet to ring biopsy--was accordingly insignificant. In 9 cases only a large conization was performed. As only a small part of the cervical tissue was usually removed it is probable that the enzymatic and mechanical properties of the cervix as well as its capacity as a sperm reservoir could be preserved. The median of the observation time is 26 months, range 3 months to 5 years. At the follow up the colposcopic and histological picture has so far shown no sign of atypia in 91 subjects. The same applies cytologically to the patients subjected to a large conization. Two women have moved away from the district. A relapse occurred in 4 patients, who after a large conization have remained cytologically negative. Throughout the investigation the term a typia has been used to characterize the cytological, colposcopic and histological changes, the degree and extension of this atypia being taken into considertion. Thus the abstruse nomenclature in common use is avoided. Cytological atypia is cellular in character, while histologically it includes the degree of structural derangement of the epithelial architecture as well. Colposcopically the angioarchitecture and the capillary distance seem to be the most important features. The correlation between the colposcopic and the cytological and histological findings is high when the degree of atypia is marked. It is inferred, therefore, that the descriptive term atypia should replace the superfluos bulk of terms in the fields in question.

Colposcopy↗