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Biomedical subjects

S Berglund

Publications and source records attributed to S Berglund.

At least 19 recordsLinked to original sources
PubMed2000

Sexual abuse during childhood and adolescence among Nicaraguan men and women: a population-based anonymous survey.

AIMS: The objective was to describe experiences of sexual abuse occurring before 19 years of age among men and women in León, Nicaragua and to explore the possible association to later sexual risk behavior. METHOD: A sub-sample of literate urban men and women 25-44 years of age was selected from a representative sample of households in León. After an invitation to a public health event, 154 men (53% of the invited) and 213 women (66% of those invited) participated in giving written answers to an anonymous questionnaire. RESULTS: Twenty percent of men and 26% of women reported that they had experienced sexual abuse. Women had been victims of attempted or completed rape twice as often as men, 15% as compared to 7%. Thirty-three percent of the abuse towards boys and 66% of the abuse towards girls was committed by family members. Women who had experienced attempted or completed rape were more likely to later have had a higher number of sexual partners compared to non-abused or moderately abused women. CONCLUSIONS: Sexual abuse of children and adolescents of both sexes is common in Nicaragua. The results underscore the urgent need to address this serious problem more openly, and to make more resources available for the prevention of sexual abuse and for support to victims.

Adolescent↗
PubMed2000

Impaired dark adaptation in polycythemia. Improvement after treatment.

PURPOSE: To determine if dark adaptation is reduced in individuals with polycythemia and if so whether there is any improvement in dark adaptation after treatment. METHODS: Dark adaptation was recorded monocularly by automatic dark adaptometry in ten consecutive patients with polycythemia before and after treatment. Analogue investigations were performed in 31 healthy control subjects. RESULTS: Dark adaptation was markedly impaired in the patients as compared with the control subjects. After reduction of the red cell count and normalization of the hematocrit and hemoglobin the dark adaptation was markedly improved. There was no significant change in dark vision in the control subjects negating a confounding learning effect. CONCLUSION: The findings indicate a sustained but reversible neuronal hypofunction secondary to polycythemia. As the rheological abnormality was normalized, dark adaptation was improved, probably secondary to normalized microcirculation within the retina or the brain, or both, possibly with reactivation of formerly inactive neuronal cells.

Adult↗
PubMed1999

Erythropoietin receptor mutations associated with familial erythrocytosis cause hypersensitivity to erythropoietin in the heterozygous state.

Inherited mutations in the erythropoietin receptor (EPOR) causing premature termination of the receptor cytoplasmic region are associated with dominant familial erythrocytosis (FE), a benign clinical condition characterized by hypersensitivity of erythroid progenitor cells to EPO and low serum EPO (S-EPO) levels. We describe a Swedish family with dominant FE in which erythrocytosis segregates with a new truncation in the negative control domain of the EPOR. We show that cells engineered to concomitantly express the wild-type (WT) EPOR and mutant EPORs associated with FE (FE EPORs) are hypersensitive to EPO-stimulated proliferation and activation of Jak2 and Stat5. These results demonstrate that FE is caused by hyperresponsiveness of receptor-mediated signaling pathways and that this is dominant with respect to WT EPOR signaling.

DNA-Binding Proteins↗
PubMed1997

Gender and social differences in adolescent sexuality and reproduction in Nicaragua.

PURPOSE: The aim of this research was to study gender and social differences in adolescent sexuality and reproduction, as reflected in age at first intercourse and age at first pregnancy, as a basis for future interventions in the municipality of León, Nicaragua. METHODS: In a community-based cross-sectional study including 7789 households, all women aged 15-49 years (n = 10,867) were interviewed about socioeconomic, sexual, and reproductive issues. A random subsample of men (n = 388) and women (n = 413) aged 15-49 years was interviewed in more detail about sexual patterns and reproduction. RESULTS: The median age at first intercourse for women and men was 17.8 and 16.2 years, respectively. Women's average latency period to end of first pregnancy was 22 months. There was a significant tendency to start active sexual life later among today's girls aged 15-20 years, compared to the groups 21-27, 28-35, and 36-49 years old. A similar trend was found in age at first pregnancy. These secular trends were not found among men. Age at first pregnancy for current adolescents was lower among those having less formal education. CONCLUSIONS: The short latency period between first sexual intercourse and end of first pregnancy, probably reflecting lack of access to counseling and contraception, is worrying in light of the growing sexually transmitted disease/human immunodeficiency virus threat. The secular trend of later start of reproduction, however, is a positive sign which partly may be an effect of increasing education in the Nicaraguan society.

Adolescent↗
PubMed1996

Two different mutations in codon 97 of the beta-globin gene cause Hb Malmö in Sweden.

An abnormal hemoglobin with increased oxygen affinity, Hb Malmö [alpha 2 beta 297(FG4)His-->Gln], was found to cause erythrocytosis in two apparently unrelated Swedish families. Direct nucleotide sequencing of amplified DNA demonstrated a CAC-->CAA substitution in one family and a CAC-->CAG substitution in the other. Both mutations resulted in a His-->Gln substitution in codon 97. This finding prompted us to examine the possible point mutations underlying the different hemoglobin variants reported in the literature.

Adult↗
PubMed1996

Contraceptive patterns among women and men in León, Nicaragua.

The aim was to study the contraceptive patterns among men and women in León, Nicaragua. A questionnaire about sexual, contraceptive, reproductive and socioeconomic issues was directed to 7,789 households including 22% of all women of the municipality aged 15-49 years (n = 10,867). A subsample of 388 men and 413 women aged 15-49 years was drawn at random. Refusals were less than 2%. Private interviews revealed that among fertile women who had been sexually active within the last three months, non-pregnant and wishing to avoid pregnancy, 77% were contracepting. Female sterilization was the most common contraceptive method (39%), followed by intrauterine device (16%). Even though around 60% of women at some time had tried oral contraceptives, only 13% of contraceptors used them currently. The rhythm and interruption methods together constituted only 4%. Condom use was low and mainly occasional. Contraceptive use in sexually active women aged 15-44 years was lower among those having lower education, living in rural areas, and living under poverty conditions. The predominance of female sterilization and the occasional condom use-mainly reported by men-reflects a situation of relative male control over contraception and reproduction. This probably originates from "machista" values where men having many children with different women are considered strong. There was also a significantly higher use of contraceptives among the better-off women and men compared with the extremely poor. The situation of many poor women, in a country with limited contraceptive services, is worrying considering that abortion is illegal and the threat of HIV epidemic is growing. The situation for adolescents is particularly problematic with low experience in contraceptive use.

Adolescent↗
PubMed1994

Media aids in dental distance learning.

The need for continuing education on a wide scale necessitates the use of techniques that are effective irrespective of the geographical spread or isolated locations of potential participants. This paper reviews the many possibilities for distance learning in dentistry made feasible by use of these different techniques and media.

Audiovisual Aids↗
PubMed1994

Hb Trollhättan [beta 20(B2)Val-->Glu]--a new haemoglobin variant with increased oxygen affinity causing erythrocytosis.

Erythrocytosis is sometimes caused by the presence of haemoglobin (Hb) variants with increased oxygen affinity. Here we describe a beta-globin variant found by isoelectric focusing (IEF) of Hb from a 23-year-old Swedish male with moderate erythrocytosis. Amplification of DNA corresponding to the beta-globin gene and subsequent nucleotide sequencing revealed heterozygosity for a GTG-->GAG mutation at codon 20, thus suggesting a Val-->Glu substitution, which was confirmed at the protein level. This mutation occurs at the same position as Hb Olympia [beta 20(B2)Val-->Met], another variant associated with erythrocytosis due to increased oxygen affinity. The novel variant, Hb Trollhättan [beta 20(B2)Val-->Glu], which was also associated with increased oxygen affinity, was shown to be present in three generations of the patient's family.

Adult↗
PubMed1992

Incidence of polycythemia vera in a defined population.

In this retrospective investigation from Malmö, a city well-suited for epidemiologic studies, 177 patients (88 males and 89 females) with polycythemia vera (PV) were identified between 1950 and 1984. The incidence rate (number of cases/100,000/yr) in both sexes increased significantly, being 1.0 in 1950-1959 and 2.6 in 1980-1984 (adjusted to the European age-standardized population). This is the highest rate reported to date. In 1970-1984 the highest age-specific incidence rates (number of cases/100,000/yr) were found in males greater than or equal to 80 yr and females 70-79 yr of age, being 18.3 and 14.6, respectively. A subgroup of 12 (7%) was identified where the PV diagnosis was not obvious on entry into the study but where it became clear during follow-up. 16 PV patients (9%) had verified or suspected arterial hypoxemia caused by a concomitant condition. We conclude that the increasing PV incidence rates, mainly confined to older age groups, are probably due to better case ascertainment.

Adult↗
PubMed1991

Diclofenac-induced thrombocytopenic purpura with renal and hepatic involvement.

A case of diclofenac-induced thrombocytopenic purpura in a 59-year-old woman is described. Unlike the majority of earlier cases, ours was associated with renal insufficiency and jaundice. Despite the dramatic clinical picture, with severe thrombocytopenia and marked renal insufficiency, the prognosis appears to be excellent, as is shown in our case and in similar ones reported in the literature. A high dose of steroids is the treatment of choice.

Acute Kidney Injury↗
PubMed1987

Voltage-clamp analysis of nodes of Ranvier in regenerated rat sciatic nerve.

Crush-lesioned adult rat sciatic nerves were allowed to regenerate during 70-181 days. Single large regenerated nerve fibres were isolated from levels distal to the crush site, and mounted in a feedback system for potential recordings and voltage clamp. After the experiment, each isolated fibre was fixed and embedded for morphological evaluation. Internodal lengths and fibre diameters were obtained form teased preparations of regenerated and normal sciatic nerves. The isolated regenerated fibres were excitable and had action potentials of large amplitude. TEA and 4-AP had negligible effects on the action potential and excitability properties. The time constant of the nodal segment was larger than in normal fibres. The nodal Na and K permeabilities (PNa and PK) were calculated both in absolute values and relative to the leak conductance (gL). Regenerated fibres had normal PNa/gL and PK/gL ratios. The potential dependence of PNa activation and inactivation was also normal. The isolated physiologically examined fibres had internodal lengths (L) of about 300 micron and diameters (D) of about 7-11 micron. In the teased fibre preparations L was about 300 micron (range 150-600 micron) and D was 3-11 micron. In addition, all teased regenerated nerve preparations exhibited a few scattered unusually short internodes (L less than 150 micron). In control nerves L ranged from 150 micron in the lower fibre size range (D = 2-3 micron) to 1.6 mm in the upper size range (D = 15 micron).

Action Potentials↗
PubMed1986

Nodes of Ranvier above a neuroma in the rat sciatic nerve: voltage clamp analysis and electron microscopy.

Neuroma formation was induced in adult rat sciatic nerves and the animals were allowed to survive for 1-10 months. In 10 animals single large myelinated fibres from the nerve segment above the neuroma were subjected to voltage clamp analysis. Six animals were fixed by glutaraldehyde perfusion and nodes of Ranvier or large myelinated fibres above the neuroma were examined in the electron microscope (EM). Most fibres exhibited normal action potentials, but a few had a reduced excitability and small action potentials. Some fibres had increased membrane time constant and leak conductance and a markedly increased membrane capacitance. Most of the examined nodes of Ranvier exhibited abnormally large delayed K currents, which could be blocked with 4-aminopyridine (4-AP). The Na current was normal. In the EM most large cross-cut myelinated axons were markedly atrophic, particularly after long survival times. Evaginations from the paranodal region of these axons penetrated between the terminating paranodal myelin lamellae. The nodal axolemmal undercoating could be very prominent and in some cases the nodal axon was irregular. These findings show that large myelinated peripheral nerve fibres, which are chronically disconnected from their peripheral targets, exhibit specific structural and functional abnormalities of the nodes of Ranvier.

Amputation Stumps↗
PubMed1985

Myelin sheath remodelling in regenerated rat sciatic nerve.

Adult rat sciatic nerves were subjected to a crush lesion and allowed to survive during 2 weeks-11 months. Segments of regenerated nerve were removed from exsanguinated animals and subjected to physiological analysis and light microscopic examination of teased fibres. Application of the potassium channel blocking agent 4-aminopyridine (4-AP) to regenerated nerve segments had marked effects on action potential waveform and recovery properties. When applied to normal control nerves 4-AP had minimal effects. Examination of teased preparations from the same nerves revealed the presence of two classes of internodes along regenerated nerve fibres. A majority of conventional regenerated internodes exhibited lengths (L) of at least 150 microns. Maximal L reached about 350 microns after one month survival and 550 microns 10 months later. In the individual nerve the maximal L-values tended to increase with fibre size. Most convential regenerated internodes had L-values of 200-400 microns. In addition, scattered unusually short sheaths, with L-values of 10-150 microns, were found intercalated between conventional internodes. Some intercalated sheaths had a wrinkled irregular configuration and some lacked a light-microscopically distinct myelin layer. We suggest that the occurrence of unusually short and partly distorted sheaths along regenerated fibres reflects a nodal-internodal remodelling in response to longitudinal crowding. These sites might represent foci with aberrant functional properties, possibly accounting for the 4-AP sensitivity of regenerated nerve.

4-Aminopyridine↗