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Biomedical subjects

M Hammar

Publications and source records attributed to M Hammar.

At least 91 records · Page 5Linked to original sources
PubMed1994

Prevalence and duration of hot flushes after surgical or medical castration in men with prostatic carcinoma.

A total of 77 men with prostatic carcinoma treated with orchiectomy or a gonadotropin releasing hormone analogue before September 1987 underwent evaluation by a questionnaire regarding vasomotor symptoms. Answers were received from 84% of the patients. Of 63 patients 43 (68%) reported hot flushes during treatment, while 30 (48%) still had flushes 5 years after treatment. Of the latter 30 patients 28 (median 7.6 years after treatment) had vasomotor symptoms at the time of the study. Only 13 of 43 men with vasomotor symptoms after the start of treatment had relief 5 years later. At the time of the study 13 of 30 patients (more than 40%) still had flushes 8 years after castration. Most men reported that the flushes presently had the same frequency and duration as when they started therapy. Contrary to the general belief that the symptoms disappear with time, our study highlighted a long persistence of hot flushes after castration.

Aged↗
PubMed1993

The RpoS sigma factor relieves H-NS-mediated transcriptional repression of csgA, the subunit gene of fibronectin-binding curli in Escherichia coli.

Curli encoded by the curlin subunit gene, csgA, are fibronectin- and laminin-binding fibres expressed by many natural Escherichia coli and E. coli K-12 strains in response to low temperature, low osmolarity and stationary-phase growth conditions. Curli expression is dependent on RpoS, a sigma factor that controls many stationary phase-inducible genes. Many commonly used K-12 strains carry an amber mutation in rpoS. Strains able to form curli carry an amber suppressor whereas curli-negative E. coli K-12 strains, in general, are sup0. Introduction of SupD, SupE, or supF suppressors into sup0 strains resulted in expression of temperature-regulated curli. In curli-deficient, RpoS- E. coli K-12 strains, csgA is transcriptionally activated by mutations in hns, which encodes the histone-like protein H-NS. Curli expression, fibronectin binding, and csgA transcription remain temperature- and osmoregulated in such double mutants. Our data suggest that RpoS+ strains, and hence curli-proficient strains of E. coli K-12, are relieved for the transcriptional repression mediated by the H-NS protein upon accumulating RpoS as cells reach stationary phase.

Amino Acid Sequence↗
PubMed1993

Paracrystalline inclusions of a novel ferritin containing nonheme iron, produced by the human gastric pathogen Helicobacter pylori: evidence for a third class of ferritins.

An abundant 19.3-kDa Helicobacter pylori protein has been cloned, and the sequence is homologous with a ferritin-like protein produced by Escherichia coli K-12. Homologies are also present with a number of eucaryotic ferritins, as well as with the heme group-containing bacterioferritins. All amino acids involved in chelation of inorganic iron by ferritins from humans and other higher species are conserved in the H. pylori protein. Consistent with the structural data indicating an iron-binding function, E. coli overexpressing the H. pylori ferritin-like protein accumulates almost 10 times more nonheme iron than vector controls, and the iron-binding activity copurifies with the 19.3-kDa protein. Immunoelectron microscopy of H. pylori, as well as of E. coli overexpressing the H. pylori gene, demonstrates that the gene product has a cytoplasmic location where it forms paracrystalline inclusions. On the basis of these structural and functional data, we propose that the H. pylori gene product (termed Pfr) forms the basis for a second class of bacterial ferritins designed to store nonheme iron.

Amino Acid Sequence↗
PubMed1993

Hormonal replacement therapy and sexuality in a population of Swedish postmenopausal women.

All women (n = 2465) living in the community of Linköping, Sweden, aged 55, 57, 59 and 65 years were studied in a cross-sectional trial concerning the prevalence of vasomotor symptoms, hormonal replacement therapy (HRT) and sexual activities. After one reminder, answers were received from 1867 (76%) women. In all, 51% of the women reported vasomotor symptoms. Ten percent of the women used HRT at the time of the survey. Another 10% of the women had previously used oral HRT but had abandoned treatment. One third of these women reported no vasomotor symptoms when they abandoned treatment. One fifth ceased treatment after recommendation from their physician and another fifth because of 'fear' of hormonal treatment. Sixty-two percent of the women reported sexual activity. The most common reasons for not having a regular sex-life were lack of partner or lack of desire.

Adult↗
PubMed1993

Environmental regulation of curli production in Escherichia coli.

Curli are novel surface organelles on E. coli that mediate binding to soluble matrix proteins. The expression of curli is affected by environmental factors, such as temperature, osmolarity, and growth conditions. Curli formation is regulated at the level of transcription, in that the csgA gene can be transcriptionally activated by the cytosolic Crl protein or transcriptionally relieved by a mutation in hns. The expression of curli is also dependent on functional RpoS. E. coli--expressing curli bind to human skin tissue, provided they are precoated with soluble fibronectin, suggesting that curli may act as a colonization factor in host-microbe interactions. Fibronectin is a multifunctional extracellular matrix and plasma protein involved in cell adhesion and cell spreading. It also interacts with a variety of microorganisms, and thus the role of fibronectin in mediating binding of curliated E. coli is of great interest. An investigation of the epitopes of both the fibronectin molecule and the curlin subunit protein involved in the binding of E. coli to tissue will give us more insight into the initial colonization of host surfaces by bacteria.

Amino Acid Sequence↗
PubMed1992

Plasma lipid and lipoprotein effects of transdermal administration of estradiol and estradiol/norethisterone acetate.

To evaluate the effect of transdermal sequential treatment with estradiol and estradiol/norethisterone acetate on lipoprotein metabolism, 25 postmenopausal women received treatment for 12 cycles of 4 weeks each (2 weeks estradiol 50 micrograms/day and 2 weeks a combined patch delivering norethisterone acetate 0.25 mg/day and estradiol 50 micrograms/day). Blood samples for lipoprotein analyses were drawn before treatment and in estrogen and combined phases in cycles 3 and 12. Plasma total cholesterol, low (LDL) and high (HDL) density lipoprotein were all significantly reduced in both estrogen and combined phases. Eighteen of the women continued the treatment for 36 cycles. In this group the HDL-cholesterol had returned to baseline values in combined phase in cycle 24. Plasma cholesterol and LDL-cholesterol values remained significantly reduced throughout the whole study compared to the pre-trial values. The present study by transdermal sequential hormonal treatment results in a lipid and lipoprotein pattern with reduced total cholesterol and LDL cholesterol in postmenopausal women.

Administration, Cutaneous↗
PubMed1992

Endometrial effects of transdermal estradiol/norethisterone acetate.

The efficacy of transdermal norethisterone acetate in sequence with transdermal estradiol has been investigated in a multicenter study of 136 post-menopausal women to determine the incidence of endometrial hyperplasia, the effects on the vaginal cytology and the control of bleeding. Treatment consisted of 12 cycles of 4 weeks each (2 weeks estradiol 50 micrograms/day followed by 2 weeks of a new combined patch delivering norethisterone acetate 0.25 mg/day and estradiol 50 micrograms/day). Endometrial histology was assessed by two pathologists. Of the 136 pre-treatment biopsies 89% provided no material, an inadequate sample or an inactive (atrophic or non-secretory) endometrium. Of the post-treatment biopsies from 110 women who completed the study: 65% showed secretory, 3% proliferative and 24% inadequate material or inactive endometrium. Hyperplasia was found in two biopsies (2%); in one of these focal atypical hyperplasia was agreed by both pathologists, in another a hyperplastic endometrial polyp was diagnosed by one pathologist. The bleeding was regular in 80% of the 1195 cycles and irregular in 11%. No bleeding occurred in 9% of the cycles. Vaginal cytology showed a significant shift towards increased maturation during treatment.

Administration, Cutaneous↗
PubMed1992

Long-term effect of transdermal hormonal therapy on aspects of quality of life in postmenopausal women.

The long-term effect on aspects of quality of life (QoL) of treatment with transdermal oestrogen for 2 weeks followed by transdermal oestrogen/progestogen norethisterone acetate/oestradiol TTS 0.25/0.05 mg/day for the next 2 weeks was investigated in postmenopausal women within the framework of a 1-year seven-centre trial. Of the 136 women who were included (mean age 53 +/- 4.8 years), 110 completed the study. Aspects of QoL that are of relevance in the perimenopause and postmenopause were evaluated using the Psychological General Well-Being (PGWB) index, the Women's Health Questionnaire (WHQ) and the Sleep Dysfunction Scale before and after 3 and 9 months of therapy in the oestrogen phase. Climacteric complaints were also assessed by means of the Kupperman Index. Improved well-being, i.e. less anxiety and depression, increased vitality and better self-control (P less than 0.0001) were observed, as well as reduced sleep disturbance (P less than 0.0001). The WHQ showed decreased vasomotor and somatic symptoms, and improved sex life, emotions and cognitive function (P less than 0.0001). Improvement was the same at 3 and 9 months. According to the Kupperman Index, climacteric symptoms were alleviated (P less than 0.0001). Relief of vasomotor symptoms was correlated with improvement in the WHQ (r = 0.82), the PGWB index (r = 0.58, P less than 0.0001) and sleep (r = 0.51, P less than 0.0001). Because of the absence of a placebo control group, the results must be regarded with caution until confirmed in a placebo-controlled trial.

Administration, Cutaneous↗
PubMed1992

Rapid detection of Helicobacter pylori in gastric biopsy material by polymerase chain reaction.

By using primers based on the sequence of a species-specific antigen of Helicobacter pylori (P. O'Toole, S.M. Logan, M. Kostrzynska. T. Wadström, and T.J. Trust, J. Bacteriol. 173:505-513, 1991), a protocol was established for detection of this microorganism in gastric biopsy samples by the polymerase chain reaction (PCR). A single primer pair was used to specifically amplify a 298-bp sequence in a rapid two-step PCR. The primers exhibited the same specificity in PCR as that which we reported for the species-specific gene probe on which they were based. The sensitivity of the method was 20 copies of the target sequence, or 70 bacterial cells, under the lysis conditions used for patient-derived material. When amplification was performed for a saturating number of cycles, visual examination of ethidium bromide-stained gels successfully detected all samples subsequently judged to be positive by Southern hybridization of the gel with a probe specific for the PCR product. The bacterium could be detected in gastric biopsy samples from patients with various gastric diseases, including samples from which the bacterium could not be cultured. Only 9 of 19 patients who tested positive by PCR of gastric biopsy material were positive when a saliva sample was analyzed. Protocols for sample handling which minimized the risk of contamination while maximizing the sensitivity of the reaction were established. The results support a role for PCR in the rapid identification of H. pylori in clinical samples.

Adult↗
PubMed1990

Comparison between the influence of methylergometrine and oxytocin on the incidence of retained placenta in the third stage of labour.

Twenty randomly selected birth centres were questioned about their oxytocic use in the third stage of labour and incidence of retained placenta in relation to the number of vaginal deliveries during 1987. Ten centres used either methylergometrine or oxytocin routinely. Of 6,906 vaginal deliveries treated with 0.2 mg methylergometrine immediately after birth, 187 (2.7%) were complicated by retained placenta. Significantly fewer (p less than 0.001) of the 10,680 vaginal deliveries treated with 5-10 IU oxytocin were complicated by retained placenta (n = 192; 1.8%).

Cesarean Section↗