Studies on in vitro S-methylation of naturally occurring thiol compounds with N-methyl-N-nitrosourea and methyl methanesulfonate

N-Methyl-N-nitrosourea (MNU) and methyl methanesulfonate (MMS) were found to rapidly methylate glutathione (GSH) in vitro yielding S-methyl glutathione, as verified and quantitated by high-performance liquid chromatography and thin-layer chromatography. Formation of S-methylcysteine in the acid-hydrolyzate of the methylated GSH further confirmed the formation of S-methyl glutathione. Other naturally occurring thiol compounds such as cysteine and homocysteine were also methylated by MNU. The observed pH dependency of GSH methylation by MNU suggests that the sulfide anion form of the thiol may represent the favored methyl acceptor. The high reactivity of GSH toward MNU and MMS may be of biological significance in that it could compete with macromolecular cellular components as a target for alkylation.     

“Dark” (compacted) neurons may not die through the necrotic pathway

Dark neurons were produced in the cortex of the rat brain by hypoglycemic convulsions. In the somatodendritic domain of each affected neuron, the ultrastructural elements, except for disturbed mitochondria, were remarkably preserved during the acute stage, but the distances between them were reduced dramatically (ultrastructural compaction). Following a 1-min convulsion period, only a few neurons were involved and their environment appeared undamaged. In contrast, 1-h convulsions affected many neurons and caused swelling of astrocytic processes and neuronal dendrites (excitotoxic neuropil). A proportion of dark neurons recovered the normal structure in 2 days. The non-recovering dark neurons were removed from the brain cortex through two entirely different pathways. In the case of 1-h convulsions, their organelles swelled, then disintegrated and finally dispersed into the neuropil through large gaps in the plasma membrane (necrotic-like removal). Following a 1-min convulsion period, the non-recovering dark neurons fell apart into membrane-bound fragments that retained the compacted interior even after being engulfed by astrocytes or microglial cells (apoptotic-like removal). Consequently, in contrast to what is generally accepted, the dark neurons produced by 1-min hypoglycemic convulsions do not die as a consequence of necrosis. As regards the case of 1-h convulsions, it is assumed that a necrotic-like removal process is imposed, by an excitotoxic environment, on dark neurons that previously died through a non-necrotic pathway. Apoptotic neurons were produced in the hippocampal dentate gyrus by intraventricularly administered colchicine. After the biochemical processes had been completed and the chromatin condensation in the nucleus had reached an advanced phase, the ultrastructural elements in the somatodendritic cytoplasm of the affected cells became compacted. If present in an apparently undamaged environment such apoptotic neurons were removed from the dentate gyrus through the apoptotic sequence of morphological changes, whereas those present in an impaired environment were removed through a necrotic-like sequence of morphological changes. This suggests that the removal pathway may depend on the environment and not on the death pathway, as also assumed in the case of the dark neurons produced by hypoglycemic convulsions.     

Educating fathers to improve breastfeeding rates and paternal-infant attachment

Objectives

To determine the effect of breastfeeding education provided to fathers on breastfeeding rates and paternal-infant attachment.

Methods

117 couples with their infants with the inclusion criteria: knowledge of reading, writing and speaking Turkish; living in the Turkish Republic of North Cyprus until their infants were six months old; and infants having no health problems preventing the early initiation of breastfeeding. Participants were divided into 3 groups (2 experimental and 1 control). Breastfeeding education was provided to the mothers (20 min/d) in the first group (n=38) and to the mothers and fathers in the second group (n=39) (20 min/d/parent) until they were discharged from the hospital. This education was supplemented by a training booklet. The parents and their infants were followed until the infants were six months old. Exclusive breastfeeding rates and Paternal-Infant Attachment Scale scores at six months were main outcome measures.

Results

Exclusive breastfeeding rates (56.4%, 33.3% and 12.8%; P<0.001) and mean (SD) Paternal-Infant Attachment Scale scores [89.51(7.05), 82.37 (12.80) and 73.38 (18.67); P<0.001] were highest in the group where education was provided to both mother and father.

Conclusions

Providing breastfeeding education to fathers increases exclusive breastfeeding rates and strengthens paternal attachment.

     

The impact of birth weight and maternal history on acne, hirsutism, and menstrual disorder symptoms in Turkish adolescent girls

The aim of the study was to determine the association between birthweight, maternal medical history and acne, hirsutism, and menstrual disorder symptoms in Turkish adolescent population. Self-administered questionnaires were distributed to all volunteer female students at 15 secondary schools. The subjects' body mass index, birthweight, age at menarche, pattern of menstrual cycle, and presence of acne or hirsutism problems were recorded. Maternal obstetric parameters, menstrual cycle, presence of acne or hirsutism at present and at adolescent period were also asked. The impact of birthweight and maternal history on acne, hirsutism, and menstrual disorder symptoms was evaluated. The results of the study showed that after exclusion of subjects born prematurely, total of 1,309 students filled the questionnaires properly and included in the study. Of these students, 174 had low birthweight (LBW) (<2,500?g), 925 had appropriate (2,500-4,000?g), and 210 had high birthweight (>4,000?g). LBW students had higher incidence of menstrual disorder and acne problems (P?=?0.032 and P?=?0.011, respectively). Maternal acne and hirsutism problems were significantly often in LBW group. Multivariate analysis showed that LBW was a predictor of acne, hirsutism, and menstrual disorder at adolescent period (P?=?0.001; P?=?0.01, and 0.02, respectively). In addition, maternal menstrual disorder was also a predictor of menstrual disorder (P?=?0.035). We concluded that LBW is a good predictor of acne, hirsutism, and menstrual disorder problems in Turkish adolescent population.     

Effect of Hypericum perforatum on intraperitoneal adhesion formation in rats

Introduction

The aim of this study was to evaluate the efficacy of Hypericum perforatum for prevention of adhesion formation in rats.

Material and methods

Twenty-four female wistar rats underwent left uterine horn adhesion model. Rats were randomised into 4 groups. Group 1 (Control): Closure of abdominal incision without any agent administration. Group 2: Closure of incision after administration of intraperitoneal (i.p.) Ringer''s lactate solution. Group 3: Closure of incision after administration of i.p. olive oil (diluent of H. perforatum). Group 4: Hypericum perforatum extract (Ecodab^®) was administered i.p. before the closure of incision. Fourteen days later, relaparatomy was performed and surgical adhesion scores, inflammation and fibrosis scores were noted. Groups were compared according to these scores.

Results

There was statistical significant difference between ringer''s lactate group and olive oil group according to surgical adhesion score (p = 0.009). However, groups were not different according to inflammation and fibrosis scores (p > 0.05).

Conclusions

Despite antiinflammatory, antioxidants and antimicrobial properties of H. perforatum, our results revealed no positive effect of H. perforatum on the prevention of intraperitoneal adhesion formation.     

Recovery versus death of "dark" (compacted) neurons in non-impaired parenchymal environment: light and electron microscopic observations

The formation of massively shrunken, hyperbasophilic, hyperargyrophilic and hyper-electron-dense but not apoptotic ("dark") neurons was initiated in rat brains by means of an electric-shock and two mechanical-injury paradigms that do not cause considerable parenchymal damage in the areas investigated. The rats were killed by perfusion fixation either immediately after these instantaneous initiating insults or after a survival period ranging from 40 min to 6 days. The formation of "dark" neurons was complete in less than a few minutes. In the somatodendritic domain of each "dark" neuron, all ultrastructural elements were remarkably preserved during the acute stage, apart from a dramatic reduction of the distances between them. This ultrastructural compaction was accompanied by a marked shift of cell fluid through seemingly intact plasma membrane, mainly into surrounding astrocytic elements. The majority of the "dark" neurons regained their normal morphology and staining properties (recovery) in 4 h. Thereafter, only solitary mitochondrion-derived membranous whorls in the cytoplasm reminded of a previous morphological disturbance. The dead "dark" neurons fell apart into membrane-bound fragments that retained their sharp outlines and compacted interior even after being engulfed by astrocytes or microglial cells. The latter sequence of morphological changes can not be harmonized with the prevailing assumption, according to which "dark" neurons die through the necrotic pathway. The fate of the "dark" neurons appeared to depend on the presence or absence of serious post-insult pathophysiological circumstances in their surroundings.