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Dive into the research topics where Peter Conner is active.

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Featured researches published by Peter Conner.


Breast Cancer Research and Treatment | 2003

Breast Cell Proliferation in Postmenopausal Women During HRT Evaluated Through Fine Needle Aspiration Cytology

Peter Conner; G. Söderqvist; Lambert Skoog; T. Gräser; F. Walter; Edneia Tani; Kjell Carlström; B. von Schoultz

The basis of breast cancer risk associated with hormonal therapies may lie in the regulation of cell proliferation. In a prospective, double-blind, randomized study postmenopausal women were given continuous combined hormone replacement therapy (HRT) either as estradiol valerate 2 mg/dienogest 2 mg, (E2V/DNG) or estradiol 2 mg/noretisterone acetate 1 mg (E2/NETA) for 6 months. Fine needle aspiration (FNA) biopsies were used for immunocytochemical analysis of breast cell proliferation before and during treatment. From 45 women completing the study 135 biopsies were obtained. In the total material there was a more than 4-fold increase in proliferation between baseline and 3 months (p < 0.001). The mean percentage of MIB-1 positive breast cells increased from 2.2 to 9.1%. In some individual women values were as high as 25%. No further increase was recorded at 6 months. While numerical values were somewhat lower in the E2V/DNG group, there were no significant differences between treatments. There was a positive correlation between breast cell proliferation (MIB-1%) and circulating levels of both estradiol (rs = 0.54, p < 0.01) and estrone (rs = 0.53, p < 0.01) after 3 and 6 months of treatment. No correlations with other endogenous hormones, proteins or with the two exogenous progestogens dienogest and norethisterone were observed. Increased breast cell proliferation should probably be regarded as an unwanted side-effect during HRT. Means to identify those women with the most pronounced proliferative response should be developed. The FNA biopsy technique may be a useful tool to monitor and evaluate the proliferative response to HRT in the normal breasts of postmenopausal women.


Fertility and Sterility | 2009

Ovarian epithelial neoplasia after hormonal infertility treatment: long-term follow-up of a historical cohort in Sweden

Karin Sanner; Peter Conner; Kjell Bergfeldt; Paul W. Dickman; Karin Sundfeldt; Torbjörn Bergh; Kerstin Hagenfeldt; Per Olof Janson; Staffan Nilsson; Ingemar Persson

OBJECTIVE To study the association between hormonal infertility treatment and ovarian neoplasia. DESIGN Historical cohort study. SETTING Three university hospitals in Sweden. PATIENT(S) A total of 2,768 women assessed and treated for infertility and infertility-associated disorders between 1961 and 1975. INTERVENTION(S) Exposed women received clomiphene citrate and/or gonadotropins. MAIN OUTCOME MEASURE(S) Incidence of ovarian neoplasia. RESULT(S) No overall excess risk of invasive ovarian cancer emerged compared with the general population. In women with gonadotropin treatment for non-ovulatory disorders, the risk was elevated (standardized incidence ratio [SIR] = 5.89; 95% confidence interval [CI] 1.91-13.75); four of the five cases reported hCG treatment only, rendering the biological plausibility uncertain. Multivariate analysis within the cohort indicated that treatment with gonadotropins only was associated with an increased risk of invasive cancer (relative risk = 5.28; 95% CI 1.70-16.47). For borderline tumors, a more than threefold overall increase of tumors (SIR = 3.61; 95% CI 1.45-7.44) was noted; women exposed to clomiphene because of ovulatory disorders showed the highest risk (SIR = 7.47; 95% CI 1.54-21.83). CONCLUSION(S) Our findings of increased risk of ovarian cancer after gonadotropins and of borderline tumors after clomiphene treatment need to be interpreted with caution. However, concern is raised, and further research on the long-term safety particularly of modern hormonal infertility treatment in IVF programs is warranted.


Climacteric | 2004

A comparative study of breast cell proliferation during hormone replacement therapy : effects of tibolon and continuous combined estrogen-progestogen treatment

Peter Conner; A. Christow; Wendy M. Kersemaekers; G. Söderqvist; Lambert Skoog; K. Carlström; Edneia Tani; Mirjam Mol-Arts; B. von Schoultz

Objective To use the fine-needle aspiration (FNA) biopsy technique to compare the effects of tibolone, conventional hormone replacement therapy (HRT) and placebo on breast cell proliferation in postmenopausal women. Methods A total of 91 women were randomized to receive either estradiol 2 mg plus norethisterone acetate 1 mg (E2/NETA), tibolone 2.5 mg or placebo for 6 months in a prospective double-blind trial. Breast cell proliferation was assessed using the Ki-67/MIB-1 monoclonal antibody. Results From the 83 women who completed the study, a total of 166 FNA biopsies were obtained, and 118 of these aspirates (71%) were evaluable for MIB-1 content. Women with assessable biopsies were younger, had a lower body mass index, and had higher levels of sex hormone binding globulin and insulin-like growth factor-I than women in whom the cell yield was insufficient. During treatment with E2/NETA, there was an increase in proliferation (percentage of MIB-1) from a mean value of 2.2 to 6.4% after 6 months (p < 0.01). No significant changes were recorded during treatment with tibolone or placebo. There was a negative association between proliferation and serum levels of total (rs = −0.29, p < 0.05) and free (rs = −0.31, p < 0.03) testosterone. Conclusions Tibolone seems to have little influence on breast cell proliferation.


Annals of Medicine | 2007

Breast response to menopausal hormone therapy--aspects on proliferation, apoptosis and mammographic density.

Peter Conner

Breast cancer is the major malignancy among women in the Western world. The breast is clearly a target organ for sex steroid hormones and hormonal treatments have been associated with an increased risk of breast cancer. The balance between proliferation and apoptosis is important for breast cell homeostasis. Mammographic breast density has been identified as a strong and independent risk factor for breast cancer. It seems clear that there is a difference between various hormonal treatments with regard to their effects on breast density and cell proliferation. Also, not all women respond similarly to the same treatment. Combined estrogen and progestogen therapy generally will enhance density and proliferation more than treatment with estrogen alone. Certain constitutional and hormonal factors appear to be predictive of breast reactivity. Older women with a low body mass index respond more strongly to treatment. Estrogen levels have a positive and androgens a negative association to increase in density and proliferation. A combination of increased proliferation and decreased apoptosis could be one mechanism to explain the excess risk of breast cancer during combined estrogen/progestogen treatment. Tibolone seems to have less impact on breast response than conventional hormone therapy. Efforts should be made to identify those women with an adverse response to treatment as well as therapeutic principles with the least possible influence on the breast.


American Journal of Obstetrics and Gynecology | 2009

Breast cancer incidence after hormonal infertility treatment in Sweden: a cohort study

Chantal C. Orgéas; Karin Sanner; Per Hall; Peter Conner; Jan Holte; Staffan Nilsson; Karin Sundfeldt; Ingemar Persson; Kee Seng Chia; Sara Wedrén; Paul W. Dickman; Kamila Czene

OBJECTIVE To assess the impact of infertility treatment with causes of infertility on incidence of breast cancer. STUDY DESIGN Historical prospective cohort study of 1135 women attending major university clinics for treatment of infertility in Sweden, 1961-1976. Women were classified as users of clomiphene citrate or gonadotropins, or a combination of both therapies. Standardized incidence ratios were calculated to estimate relative risk of breast cancer. RESULTS We observed 54 cases of breast cancer during 1961-2004, which did not significantly exceed those expected. Users of high-dose clomiphene citrate had an almost 2-fold increased risk (standardized incidence ratio, 1.90; 95% confidence interval, 1.08-3.35). This association was more pronounced among women referred for nonovulatory factors, with 3-fold increased risk (standardized incidence ratio, 3.00; 95% confidence interval, 1.35-6.67). CONCLUSION No overall increased risk for breast cancer was shown with infertility treatment. Women with nonovulatory causes treated with high-dose clomiphene citrate therapy may have an elevated risk for breast cancer.


American Journal of Human Genetics | 2014

Neu-laxova syndrome is a heterogeneous metabolic disorder caused by defects in enzymes of the L-serine biosynthesis pathway

Rocio Acuna-Hidalgo; Denny Schanze; Ariana Kariminejad; Ann Nordgren; Mohamad Hasan Kariminejad; Peter Conner; Giedre Grigelioniene; Daniel Nilsson; Magnus Nordenskjöld; Anna Wedell; Christoph Freyer; Anna Wredenberg; Dagmar Wieczorek; Gabriele Gillessen-Kaesbach; Hülya Kayserili; Nursel Elcioglu; Siavash Ghaderi-Sohi; Payman Goodarzi; Hamidreza Setayesh; Maartje van de Vorst; Marloes Steehouwer; Rolph Pfundt; Birgit Krabichler; Cynthia J. Curry; Malcolm MacKenzie; Kym M. Boycott; Christian Gilissen; Andreas R. Janecke; Alexander Hoischen; Martin Zenker

Neu-Laxova syndrome (NLS) is a rare autosomal-recessive disorder characterized by a recognizable pattern of severe malformations leading to prenatal or early postnatal lethality. Homozygous mutations in PHGDH, a gene involved in the first and limiting step in L-serine biosynthesis, were recently identified as the cause of the disease in three families. By studying a cohort of 12 unrelated families affected by NLS, we provide evidence that NLS is genetically heterogeneous and can be caused by mutations in all three genes encoding enzymes of the L-serine biosynthesis pathway. Consistent with recently reported findings, we could identify PHGDH missense mutations in three unrelated families of our cohort. Furthermore, we mapped an overlapping homozygous chromosome 9 region containing PSAT1 in four consanguineous families. This gene encodes phosphoserine aminotransferase, the enzyme for the second step in L-serine biosynthesis. We identified six families with three different missense and frameshift PSAT1 mutations fully segregating with the disease. In another family, we discovered a homozygous frameshift mutation in PSPH, the gene encoding phosphoserine phosphatase, which catalyzes the last step of L-serine biosynthesis. Interestingly, all three identified genes have been previously implicated in serine-deficiency disorders, characterized by variable neurological manifestations. Our findings expand our understanding of NLS as a disorder of the L-serine biosynthesis pathway and suggest that NLS represents the severe end of serine-deficiency disorders, demonstrating that certain complex syndromes characterized by early lethality could indeed be the extreme end of the phenotypic spectrum of already known disorders.


Fertility and Sterility | 2011

Effects of percutaneous estradiol–oral progesterone versus oral conjugated equine estrogens–medroxyprogesterone acetate on breast cell proliferation and bcl-2 protein in healthy women

Daniel Murkes; Peter Conner; Karin Leifland; Edneia Tani; Aude Beliard; Eva Lundström; Gunnar Söderqvist

In a prospective, randomized clinical study 77 women were assigned randomly to receive sequential hormone therapy with either conventional oral conjugated equine estrogens (0.625 mg) with the addition on 14 of the 28 days of oral medroxyprogesterone acetate (5 mg) or natural E(2) gel (1.5 mg) with oral micronized P (200 mg) on 14 of the 28 days of each cycle. Because oral conjugated equine estrogens-medroxyprogesterone acetate induced a highly significant increase in breast cell proliferation in contrast to percutaneous E(2)-oral P with a difference between therapies approaching significance, the former therapy has a marked impact on the breast whereas natural percutaneous E(2)-oral micronized P has not.


Acta Obstetricia et Gynecologica Scandinavica | 1998

Hyperprolactinemia; etiology, diagnosis and treatment alternatives

Peter Conner; Gabriel Fried

This review article deals with hyperprolactinemia, its causes, associated symptoms, and current treatment. The objective is to review recent articles concerning pathophysiology, treatment, and therapy resistance. Hyperprolactinemia is a relatively common endocrine abnormality caused by an increased secretion of prolactin (PRL) from the pituitary gland. Hyperprolactinemia causes anovulation and infertility but can affect women of all ages and therefore should be considered in issues dealing with reproduction and menopause. The etiology as well as the natural history of hyperprolactinemia can vary widely. Better awareness in this regard is important in order to determine treatment and evaluation of patients with hyperprolactinemia.


Clinical Obstetrics and Gynecology | 2008

Breast cancer and hormonal therapy.

Peter Conner; Eva Lundström; Bo von Schoultz

Valid evidence from randomized-controlled trials indicates that breast cancer risk is increased with combined estrogen/progestogen use and that such treatment implies a risk greater than that of estrogen alone. Overall, risk estimates from observational studies are somewhat higher than in randomized-controlled trials but remain modest as compared with other risk factors even after long-term treatment. For combined estrogen/progestogen therapy, risk increases gradually to reach statistical significance after 4 to 5 years. Apart from its many beneficial health effects, the safety data for use of estrogen alone are quite reassuring. The only justifications for progestogen addition are for bleeding control and endometrial protection. At present, there are several new therapeutic compounds and concepts in development, which hold promise to provide both endometrial protection and breast safety.


European Journal of Human Genetics | 2016

A novel phenotype in N-glycosylation disorders: Gillessen-Kaesbach-Nishimura skeletal dysplasia due to pathogenic variants in ALG9.

Emma Tham; Erik Eklund; Anna Hammarsjö; Per Bengtson; Stefan Geiberger; Kristina Lagerstedt-Robinson; Helena Malmgren; Daniel Nilsson; Gintautas Grigelionis; Peter Conner; Peter Lindgren; Anna Lindstrand; Anna Wedell; Margareta Albåge; Katarzyna Zielinska; Ann Nordgren; Nikos Papadogiannakis; Gen Nishimura; Giedre Grigelioniene

A rare lethal autosomal recessive syndrome with skeletal dysplasia, polycystic kidneys and multiple malformations was first described by Gillessen-Kaesbach et al and subsequently by Nishimura et al. The skeletal features uniformly comprise a round pelvis, mesomelic shortening of the upper limbs and defective ossification of the cervical spine. We studied two unrelated families including three affected fetuses with Gillessen-Kaesbach–Nishimura syndrome using whole-exome and Sanger sequencing, comparative genome hybridization and homozygosity mapping. All affected patients were shown to have a novel homozygous splice variant NM_024740.2: c.1173+2T>A in the ALG9 gene, encoding alpha-1,2-mannosyltransferase, involved in the formation of the lipid-linked oligosaccharide precursor of N-glycosylation. RNA analysis demonstrated skipping of exon 10, leading to shorter RNA. Mass spectrometric analysis showed an increase in monoglycosylated transferrin as compared with control tissues, confirming that this is a congenital disorder of glycosylation (CDG). Only three liveborn children with ALG9-CDG have been previously reported, all with missense variants. All three suffered from intellectual disability, muscular hypotonia, microcephaly and renal cysts, but none had skeletal dysplasia. Our study shows that some pathogenic variants in ALG9 can present as a lethal skeletal dysplasia with visceral malformations as the most severe phenotype. The skeletal features overlap with that previously reported for ALG3- and ALG12-CDG, suggesting that this subset of glycosylation disorders constitutes a new diagnostic group of skeletal dysplasias.

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Marius Kublickas

Karolinska University Hospital

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Giedre Grigelioniene

Karolinska University Hospital

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Sven Gustafsson

Karolinska University Hospital

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G. Söderqvist

Karolinska University Hospital

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J. Hammarqvist Vejde

Karolinska University Hospital

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Kjell Carlström

Karolinska University Hospital

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Lambert Skoog

Karolinska University Hospital

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