The rate of cell growth is governed by cell cycle stage

Cell growth is an essential requirement for cell cycle progression. While it is often held that growth is independent of cell cycle position, this relationship has not been closely scrutinized. Here we show that in budding yeast, the ability of cells to grow changes during the cell cycle. We find that cell growth is faster in cells arrested in anaphase and G1 than in other cell cycle stages. We demonstrate that the establishment of a polarized actin cytoskeleton—either as a consequence of normal cell division or through activation of the mating pheromone response—potently attenuates protein synthesis and growth. We furthermore show by population and single-cell analysis that growth varies during an unperturbed cell cycle, slowing at the time of polarized growth. Our study uncovers a fundamental relationship whereby cell cycle position regulates growth.     

Cardiac metastasis of liposarcoma

The authors describe a retroperitoneal liposarcoma with secondary involvement of the left ventricle. Therapy has been disappointing, and is guided by the nature of the primary tumor, previous therapy, extent of metastatic spread, and feasibility of cardiac resection. In selected patients whose primary tumor is well-controlled and progressing slowly, with no evidence of widespread disease, resection of the cardiac metastases can be performed when technically feasible.     

Early sequential formation of functional GABA(A) and glutamatergic synapses on CA1 interneurons of the rat foetal hippocampus

During postnatal development of CA1 pyramidal neurons, GABAergic synapses are excitatory and established prior to glutamatergic synapses. As interneurons are generated before pyramidal cells, we have tested the hypothesis that the GABAergic interneuronal network is operative before glutamate pyramidal neurons and provides the initial patterns of activity. We patch-clamp recorded interneurons in foetal (69 neurons) and neonatal P0 (162 neurons) hippocampal slices and performed a morphofunctional analysis of biocytin-filled neurons. At P0, three types of interneurons were found: (i) non-innervated "silent" interneurons (5%) with no spontaneous or evoked synaptic currents; (ii) G interneurons (17%) with GABA(A) synapses only; and (iii) GG interneurons with GABA and glutamatergic synapses (78%). Relying on the neuronal capacitance, cell body size and arborization of dendrites and axons, the three types of interneurons correspond to three stages of development with non-innervated neurons and interneurons with GABA(A) and glutamatergic synapses being, respectively, the least and the most developed. Recordings from both pyramidal neurons and interneurons in foetuses (E18-20) revealed that the majority of interneurons (65%) had functional synapses whereas nearly 90% of pyramidal neurons were quiescent. Therefore, interneurons follow the same GABA-glutamate sequence of synapse formation but earlier than the principal cells. Interneurons are the source and the target of the first synapses formed in the hippocampus and are thus in a position to modulate the development of the hippocampus in the foetal stage.     

Dimensions and predictions of professional involvement in self-help groups: a view from within

This article focuses on an analysis of how members of self-help groups perceived professional involvement and what they defined as the dimensions of such involvement. Models to predict these identified dimensions are also suggested. The instrument developed for the study consisted of two parts: (1) demographic question and (2) 12 statements concerning self-help group members' attitudes toward professional involvement. Based on responses from 183 members of self-help groups, three categories were identfied according to their main focus: groups dealing with health issues, groups dealing with alternative lifestyles, and groups based on the 12-step model. Analysis yielded two conceptually different constructs influencing group members' attitudes: collaboration and duality.     

Pre-term delivery,optimism and initial personal growth as predictors of mothers’ long-term personal growth

Introduction: Positive outcomes in the aftermath of childbirth have increasingly been studied in the last decade. However, most of the studies concentrate on short-term outcomes. The current study examined the perceived personal growth of mothers four years after childbirth, investigating the contribution of the event characteristics (full-term/pre-term birth), internal resources (optimism, self-esteem) and personal growth as measured one year after the birth.

Methods: Mothers (n=259) participated in the study by completing a set of self-report questionnaires one and four years following the birth of their child/ren.

Results: Personal growth after four years was found to be higher among mothers of pre-terms than of full-terms, and higher four years after the birth than it had been three years earlier. Furthermore, regression analysis indicated the significant contributions of being a mother to pre-term baby/ies, optimism and personal growth one year after the birth to women’s personal growth three years later.

Discussion: The results highlight the potential long-term effects of giving birth to a pre-term baby on personal growth, as well as the contribution of optimism as an important internal resource. They also indicate the development of personal growth over time. Explanations for the findings are offered and their practical implications are discussed.     

Neuronal migration disorders: Heterotopic neocortical neurons in CA1 provide a bridge between the hippocampus and the neocortex

Neuronal migration disorders have been involved in various pathologies, including epilepsy, but the properties of the neural networks underlying disorders have not been determined. In the present study, patch clamp recordings were made from intrahippocampal heterotopic as well as from neocortical and hippocampal neurons from brain slices of rats with prenatally methylazoxymethanol-induced cortical malformation. We report that heterotopic neurons have morphometrical parameters and cellular properties of neocortical supragranular neurons and are integrated in both neocortical and hippocampal networks. Thus, stimulation of the white matter induces both antidromic and orthodromic response in heterotopic and neocortical neurons. Stimulation of hippocampal afferents evokes a monosynaptic response in the majority of heterotopic neurons and a polysynaptic all-or-none epileptiform burst in the presence of bicuculline to block γ-aminobutyric acid type A inhibition. Furthermore, hippocampal paroxysmal activity generated by bath application of bicuculline can spread directly to the neocortex via the heterotopia in methylazoxymethanol-treated but not in naive rats. We conclude that heterotopias form a functional bridge between the limbic system and the neocortex, providing a substrate for pathological conditions.     

Hemodynamic changes during a new procedure for regional chemotherapy involving occlusion of the thoracic aorta and inferior vena cava

Study Objective: To describe the hemodynamic consequences of a regional chemotherapy procedure involving occlusion of the thoracic aorta and inferior vena cava (IVC) by intraluminal balloons.

Design: Prospective study.

Setting: Operating rooms of an academic hospital.

Patients: 10 patients with inoperable intraabdominal malignancy.

Interventions: After the induction of general anesthesia and the insertion of a pulmonary artery catheter the patients underwent the regional chemotherapy procedure

Measurements and Main Results: Occlusion of the thoracic aorta induced an increase in blood pressure (BP) and systemic vascular resistance (SVR) (41% ± 8% and 80% ± 15% from baseline, respectively), and a 30% ± 7% decrease in cardiac output (CO). After aortic balloon deflation at the end of the procedure, we observed a decrease in BP to baseline values, decrease in SVR (to 62% ± 12% below baseline), and increase in CO (to 80% ± 15% above baseline). Those changes resemble those described during vascular surgery. Isolated occlusion of the IVC before aortic occlusion caused hemodynamic deterioration in only three of 10 patients, suggesting incomplete obstruction or collateral blood flow in others. Occluding the IVC while the aorta was occluded, caused minimal hemodynamic changes.

Conclusions: Independent inflation of the IVC balloon should not be performed routinely because of possible unpredicted hemodynamic instability. Inferior vena cava occlusion should always be performed after complete aortic occlusion, because it is then that it produces negligible hemodynamic consequences. It is possible that a better assessment of IVC occlusion after balloon inflation needs to be done by contrast injection to prevent a possible leak of chemotherapeutic drugs.     

Distribution of GABAergic neurons in late fetal and early postnatal rat hippocampus

The ontogenesis of GABAergic neurons in the rat hippocampus was studied using an anti-GABA serum. GABA immunoreactivity appeared at the 18th day of gestation. At this stage, GABA-immunoreactive (GABA-IR) cells are grouped in two layers, one located deeply in the intermediate zone near the ventricular zone, and the other found superficially in the marginal zone near the hippocampal fissure. During the late embryonic and early postnatal life, GABA-IR neurons progressively disappeared from these two layers. The transient appearance of an abundant network of GABAergic neurons might be due to transient expression of GABA in some neurons or to cellular death. Later on, from the third postnatal day, the GABA-IR neurons appeared throughout the whole hippocampus according to a dorsoventral and lateromedial gradient. The setting of neuronal bodies preceded that of GABA-IR puncta (supposed to be mainly synaptic boutons) around the neuronal cell bodies and along the dendritic shafts. The puncta are only visible from the sixth day onwards and their number increased rapidly during the first 3 postnatal weeks. Our results indicate that GABA may have a role in neurotransmission in the hippocampus from a very early stage of development.