Transient Increased Research Articles

Safety of cervical transforaminal epidural steroid injections

BackgroundIn 2014 the FDA issued a drug safety warning that steroids in the epidural space may result in rare but serious neurological adverse events. The FDA identified 131 cases of neurological adverse events and most complications were related to cervical transforaminal epidural injections (TFESIs). These complications occurred before the standard use of non-particulate steroids. Many still consider cervical TFSEIs to be unsafe. ObjectivesThe objective of this study was to evaluate the safety of cervical TFESIs with non-particulate steroids. MethodsA review was done of all cervical TFESIs from 2004 to 2021 at an academic institution when non-particulate steroids became more commonly used by reviewing CPT code 64479 linked to the performing physician. All treating physicians and department directors were queried about catastrophic complications (stroke, spinal cord injury, death or other). A secondary analysis was done on 200 consecutive cervical TFESIs looking at immediate and delayed side-effects documented by the nurse in recovery, day-after phone calls and clinic follow-up notes. ResultsFrom 2004 to 2021 the CPT code 64479 was used 6967 times, with 6241 cervical TFESIs and 726 thoracic TFESIs. No catastrophic complications occurred. In the subset analysis of 200 consecutive cervical TFESIs, 7 patients (3.5 %, 95 % CI 1.0–6.0) had a transient increase in pain, 18 (9 %, 95 % CI 5.0–13.0) had no change in pain and 171 (85.5 %, 95 % CI 80.6–90.4) had a decrease in pain. The average pain score among all participants dropped 3.7 (95 % 3.0–4.4) points. A 2-point drop was seen in 75.5 % (95 % CI 69.5–81.5) and a 3-point drop was seen in 62.5 % (95 % CI 59.1–65.9). Five of the seven patients with transient increased pain had an increase of ≥ 3 points on numerical rating scale. There was one of each of the following reported: insomnia, glucose >500, transient thumb numbness with pain, and hypertension. Two cases of headaches were reported. ConclusionThis study supports the safety of cervical TFESIs with non-particulate steroids as recommended by consensus opinions from medical societies.

Ciliated Cells Express a Novel Pattern of Brain-Derived Neurotrophic Factor in Allergic Rhinitis.

Mounting research indicates that brain-derived neurotrophic factor (BDNF), has great potential to increase neuro-hyperresponsiveness and airway resistance in airway allergic disease. The expression level of BDNF has been found to be notably elevated in lung/nasal lavage (NAL) fluid. However, the expression and position of BDNF in ciliated cells with allergic rhinitis remains unclear. Nasal mucosal cells were collected from patients with allergic rhinitis (AR) and mice which were performed under different allergen challenge time, then observed the expression and position of BDNF located in ciliated cells through the immunofluorescence staining. Nasal mucosa, serum and NAL fluid were collected also. The expression level of BDNF and IL-4/5/13 were detected by RT-PCR. The expressions of BDNF (in serum and NAL fluid), and total-IgE, ovalbumin sIgE (in serum) were detected by ELISA. We found that MFI of BDNF in AR group's ciliated cells was obviously lower than that in the control group, and a negative correlation was discovered between MFI and VAS score. It can be roughly divided into 5 patterns according to its location in the cytoplasm of ciliated cells. In the mouse model, the expressions of BDNF in serum and NAL fluid increased temporarily after allergen stimulation. The MFI of BDNF in ciliated cells displayed an initial increase followed by a subsequent decrease. Our study shows for the first time that, the expression and localization of BNDF were observed in the human nasal ciliated epithelial cells of allergic rhinitis, and the expression of level was less than the control group under the persistent state of allergy. BDNF expression in ciliated cells was transient increased after allergen stimulation and decreased to normal level after 24h in mouse model of allergic rhinitis. This might be the possible source of the transient increase of BNDF in serum and NAL fluid.

Transient IL-33 upregulation in neonatal mouse lung promotes acute but not chronic type 2 immune responses induced by allergen later in life.

Early life respiratory insults, such as viral infections or hyperoxia, often increase asthma susceptibility later in life. The mechanisms underlying this increased susceptibility are not fully understood. IL-33 has been shown to be critically involved in allergic airway diseases. IL-33 expression in the neonatal lung can be increased by various respiratory insults associated with asthma development. Therefore, we investigated whether and how early life increases in IL-33 impact allergic airway responses later in life. Using a novel IL-33 transgenic mouse model, in which full-length IL-33 was inducible overexpressed in lung epithelial cells, we transiently upregulated lung IL-33 expression in neonatal mice for one week. After resting for 4-6 weeks, mice were intranasally exposed to a single-dose of recombinant IL-33 or the airborne allergen Alternaria. Alternatively, mice were exposed to Alternaria and ovalbumin multiple times for one month. We found that a transient increase in IL-33 expression during the neonatal period promoted IL-5 and IL-13 production when mice were later exposed to a single-dose of IL-33 or Alternaria in adulthood. However, increased IL-33 expression during the neonatal period did not affect airway inflammation, type 2 cytokine production, lung mucus production, or antigen-specific antibody responses when adult mice were exposed to Alternaria and ovalbumin multiple times. These results suggest that transient increased IL-33 expression early in life may have differential effects on allergic airway responses in later life, preferentially affecting allergen-induced acute type 2 cytokine production.

Corrigendum to “Single Bout Exercise in Children with Juvenile Idiopathic Arthritis: Impact on Inflammatory Markers”

[This corrects the article DOI: 10.1155/2018/9365745.].

Single Bout Exercise in Children with Juvenile Idiopathic Arthritis: Impact on Inflammatory Markers.

Objective In a context of inflammatory disease such as juvenile idiopathic arthritis (JIA), we do not know what impact physical activity may have on a deregulated immune system. The objective is to measure the impact of a single bout of exercise on plasma inflammatory markers such as calprotectin, IL-6, sIL-6R, sgp130, and the hypothalamic-pituitary-adrenal axis in children with juvenile idiopathic arthritis. Methods Twelve children with JIA performed a nonexercise control day and a consecutive day that included a 20 min exercise bout at 70% of max-HR at 08:30 am. Venous blood samples were taken at 08:30, 08:50, 09:30, 10:30 am, and 12:00 pm to measure plasma concentrations of calprotectin, IL-6, sIL-6R, sgp130, cortisol, and ACTH. Pain was evaluated at 08:30, 08:50 am, and 06:00 pm. Results There was a transient twofold increase in postexercise self-evaluated pain (p = 0.03) that disappeared in the evening. A single bout of exercise resulted in a 1.7-fold increase in plasma calprotectin (p < 0.001) but not IL-6 and its soluble receptors. Calprotectin levels returned to baseline within 3 hours after cessation of exercise. Conclusion Acute exercise in children with JIA induced slightly musculoskeletal leg pain and transient increased plasma calprotectin levels but not IL-6 levels. Trial registration in ClinicalTrials.gov, reference number NCT 02502539, registered on 29 May 2015.

Long-term outcomes after surgical treatment of pediatric neurogenic thoracic outlet syndrome.

OBJECTIVE Neurogenic thoracic outlet syndrome (nTOS) is an uncommon compression syndrome of the brachial plexus that presents with pain, sensory changes, and motor weakness in the affected limb. The authors reviewed the clinical presentations and outcomes in their series of pediatric patients with surgically treated nTOS over a 6-year period. METHODS Cases of nTOS in patients age 18 years or younger were extracted for analysis from a prospective database of peripheral nerve operations. Baseline patient characteristics, imaging and neurophysiological data, operative findings, and outcomes and complications were assessed. RESULTS Twelve patients with 14 cases of nTOS surgically treated between April 2010 and December 2016 were identified. One-third of the patients were male, and 2 male patients underwent staged, bilateral procedures. Disabling pain (both local and radiating) was the most common presenting symptom (100%), followed by numbness (35.7%), then tingling (28.6%). The mean duration of symptoms prior to surgery was 15.8 ± 6.6 months (mean ± SD). Sports-related onset of symptoms was seen in 78.6% of cases. Imaging revealed cervical ribs in 4 cases, prominent C-7 transverse processes in 4 cases, abnormal first thoracic ribs in 2 cases, and absence of bony anomalies in 4 cases. Neurophysiological testing results were normal in 85.7% of cases. Conservative management failed in all patients, with 5 patients reporting minimal improvement in symptoms with physical therapy. With a mean follow-up after surgery of 22 ± 18.3 months (mean ± SD), pain relief was excellent (> 90%) in 8 cases (57.1%), and good (improved > 50%) in 6 cases (42.9%). On univariate analysis, patients who reported excellent pain resolution following surgery at long-term follow-up were found to be significantly younger, and to have suffered a shorter duration of preoperative symptoms than patients who had worse outcomes. Lack of significant trauma or previous surgery to the affected arm was also associated with excellent outcomes. There were 4 minor complications in 3 patients within 30 days of surgery: 1 patient developed a small pneumothorax that resolved spontaneously; 1 patient suffered a transient increase in pain requiring consultation, followed by hiccups for a period of 3 hours that resolved spontaneously; and 1 patient fell at home, with transient increased pain in the surgically treated extremity. There were no new neurological deficits, wound infections, deep vein thromboses, or readmissions. CONCLUSION Pediatric nTOS commonly presents with disabling pain and is more frequently associated with bony anomalies compared with adult nTOS. In carefully selected patients, surgical decompression of the brachial plexus results in excellent pain relief, which is more likely to be seen in younger patients who present for early surgical evaluation.

Isolation stress and chronic mild stress induced immobility in the defensive burying behavior and a transient increased ethanol intake in Wistar rats.

Stress can be experienced with or without adverse effects, of which anxiety and depression are two of the most important due to the frequent comorbidity with alcohol abuse in humans. Historically, stress has been considered a cause of drug use, particularly alcohol abuse due to its anxiolytic effects. In the present work we exposed male Wistar rats to two different stress conditions: single housing (social isolation, SI), and chronic mild stress (CMS). We compared both stressed groups to group-housed rats and rats without CMS (GH) to allow the determination of a clear behavioral response profile related to their respective endocrine stress response and alcohol intake pattern. We found that SI and CMS, to a greater extent, induced short-lasting increased sucrose consumption, a transient increase in serum corticosterone level, high latency/immobility, and low burying behavior in the defensive burying behavior (DBB) test, and a transient increase in alcohol intake. Thus, the main conclusion was that stress caused by both SI and CMS induced immobility in the DBB test and, subsequently, induced a transient increased voluntary ethanol intake in Wistar rats with a free-choice home-cage drinking paradigm.

Roles of the NMDA Receptor and EAAC1 Transporter in the Modulation of Extracellular Glutamate by Low and High Affinity AMPA Receptors in the Cerebellum in Vivo: Differential Alteration in Chronic Hyperammonemia.

The roles of high- and low-affinity AMPA receptors in modulating extracellular glutamate in the cerebellum remain unclear. Altered glutamatergic neurotransmission is involved in neurological alterations in hyperammonemia, which differently affects high- and low-affinity AMPA receptors. The aims were to assess by in vivo microdialysis (a) the effects of high- and low-affinity AMPA receptor activation on extracellular glutamate in the cerebellum; (b) whether chronic hyperammonemia alters extracellular glutamate modulation by high- and/or low-affinity AMPA receptors; and (c) the contribution of NMDA receptors and EAAC1 transporter to AMPA-induced changes in extracellular glutamate. In control rats, high affinity receptor activation does not affect extracellular glutamate but increases glutamate if NMDA receptors are blocked. Low affinity AMPA receptor activation increases transiently extracellular glutamate followed by reduction below basal levels and return to basal values. The reduction is associated with transient increased membrane expression of EAAC1 and is prevented by blocking NMDA receptors. Blocking NMDA receptors with MK-801 induces a transient increase in extracellular glutamate which is associated with reduced membrane expression of EAAC1 followed by increased membrane expression of the glutamate transporter GLT-1. Chronic hyperammonemia does not affect responses to activation of low affinity AMPA receptors. Activation of high affinity AMPA receptors increases extracellular glutamate in hyperammonemic rats by an NMDA receptor-dependent mechanism. In conclusion, these results show that there is a tightly controlled interplay between AMPA and NMDA receptors and an EAAC1 transporter in controlling extracellular glutamate. Hyperammonemia alters high- but not low-affinity AMPA receptors.

Effects of microbeam radiation therapy on normal and tumoral blood vessels

Microbeam radiation therapy (MRT) is a new form of preclinical radiotherapy using quasi-parallel arrays of synchrotron X-ray microbeams. While the deposition of several hundred Grays in the microbeam paths, the normal brain tissues presents a high tolerance which is accompanied by the permanence of apparently normal vessels. Conversely, the efficiency of MRT on tumor growth control is thought to be related to a preferential damaging of tumor blood vessels.The high resistance of the healthy vascular network was demonstrated in different animal models by in vivo biphoton microscopy, magnetic resonance imaging, and histological studies. While a transient increase in permeability was shown, the structure of the vessels remained intact. The use of a chick chorioallantoic membrane at different stages of development showed that the damages induced by microbeams depend on vessel maturation. In vivo and ultrastructural observations showed negligible effects of microbeams on the mature vasculature at late stages of development; nevertheless a complete destruction of the immature capillary plexus was found in the microbeam paths. The use of MRT in rodent models revealed a preferential effect on tumor vessels. Although no major modification was observed in the vasculature of normal brain tissue, tumors showed a denudation of capillaries accompanied by transient increased permeability followed by reduced tumor perfusion and finally, a decrease in number of tumor vessels. Thus, MRT is a very promising treatment strategy with pronounced tumor control effects most likely based on the anti-vascular effects of MRT.

MRI study of cerebral, retinal and choroidal blood flow responses to acute hypertension

Blood flow (BF) in many tissues is stable during significant fluctuations in systemic arterial blood pressure or perfusion pressure under normal conditions. The regulatory mechanisms responsible for this non-passive BF behavior include both local and neural control mechanisms. This study evaluated cerebral BF (CBF), retinal BF (RBF) and choroidal BF (ChBF) responses to acute blood pressure increases in rats using magnetic resonance imaging (MRI). A transient increase in blood pressure inside the MRI scanner was achieved by mechanically inflating a balloon catheter to occlude the descending aorta near the diaphragm. We verified the rat model of mechanical occlusion and MRI approach by first measuring blood-flow regulatory responses to changing BP in the brain under normoxia and hypercapnia where the phenomenon is well documented. Retinal and choroidal blood-flow responses to transient increased arterial pressure were then investigated. In response to an acute increase in blood pressure, RBF exhibited autoregulatory behavior and ChBF exhibited baroregulation similar to that seen in the cerebral circulation. This approach may prove useful to investigate retinal and choroidal vascular dysregulation in rat models of retinal diseases with suspected vascular etiology.

Postpartum glycemic homeostasis in early lactating rats is accompanied by transient and specific increase of soleus insulin response through IRS2/AKT pathway

It is known that at the moment of delivery immediate lost of conceptus (main site of glucose disposal in late pregnancy) is not able to disturb glucose homeostasis in early lactating mothers. However, the mechanism by which this adaptation takes place in early lactation is still unknown. Most studies concerning insulin sensitivity in lactating rats were carried out at 11-13 days postpartum and did not describe functional changes in insulin response in early lactation. Here we show that lactation hypersensitivity to insulin is observed as early as 3 days after delivery (L3). We show that the oxidative soleus muscle displays a transient increased maximal insulin-induced glucose uptake and CO2 production, which is temporally limited to L3. Response of soleus muscle was accompanied by an increase in glucose transporter 4 (GLUT4) content at L3. This adaptive response was not detected in the glycolytic plantaris muscle, which displayed lower content of GLUT4. We also found that soleus muscle from early lactating rats have higher insulin receptor expression and tyrosine phosphorylation. Downstream steps of insulin signaling pathway; e.g., insulin receptor substrate 2 tyrosine phosphorylation and its association with phosphatidylinositol 3-kinase were also upregulated in soleus muscle. In parallel, protein tyrosine phosphatase 1B expression, a negative regulator of insulin signal, was reduced. Importantly, all of these molecular alterations were time limited to L3 and were not observed in plantaris muscle. These results suggest that improved insulin action in oxidative, but not in glycolytic muscle might contribute to achievement of glucose homeostasis postpartum.

Differential regulation of retinoblastoma protein by hormonal and antihormonal agents in T47D breast cancer cells

Phosphorylation of the tumor suppressor protein, retinoblastoma (pRb), regulates the progression of the cell cycle. Previous work from this laboratory had shown that estradiol (E 2) regulates tumor suppressor proteins, p53 and retinoblastoma in breast cancer cells. In the present study, we have examined the phosphorylation of pRB in T47D breast cancer cells following treatments with R5020 and antiprogestins. In growth medium containing serum depleted of endogenous steroids by charcoal treatment, pRb appeared mainly in its hypophosphorylated form. Addition of 10 nM R5020 to the culture medium caused hyperphosphorylation of pRb within 24 h, but the hypophosphorylated form of pRb began to accumulate after 72 h. Upon prolonged R5020 treatment (72–96 h), pRb was detected exclusively in its hypophosphorylated form. While treatment of cells with R5020 caused a transient increase in the level of cyclin D1, E 2 addition caused a sustained increase in the level of cyclin D1 consistent with its role in stimulating pRb phosphorylation. Antagonists of both estrogen receptor (ER) and progesterone receptor (PR) blocked the E 2 and R5020-induced pRb phosphorylation, respectively. These results suggest that R5020 induces pRb phosphorylation via a transient increased expression of cyclin D1, whereas E 2 treatment results in sustained expression of cyclin D1 and increased pRb phosphorylation. Furthermore, R5020 effects on pRb phosphorylation appear PR-mediated as no cross-antagonism of pRb phosphorylation was observed: the R5020 effects were blocked by RU486 and ZK98299, but not by the pure ER antagonist, ICI 182, 780 (ICI).

Transient increase in the high affinity [ 3H]- l-glutamate uptake activity during in vitro development of hippocampal neurons in culture

The glial GLAST and GLT-1 glutamate transporters are transiently expressed in hippocampal neurons as shown by immunocytochemistry (Plachez et al., 2000. J. Neurosci. Res., 59, 587–593). In order to test if this transient expression is associated to a transient glutamate uptake activity, [ 3H]-glutamate uptake was studied during the in vitro development of embryonic hippocampal neurons cultured in a defined (serum free) medium. In these cultures, the ratio of the number of glial cells to the number of neurons increased from 1.7 to 11.3% during the first 10 days of culture, while 77% of the neurons died. The number of neurons then remains stable up to 23 days of culture. The initial glutamate uptake velocity at 20 and 200 μM [ 3H]-glutamate usually increased about five times between 1 and 10 days in vitro (DIV). Interestingly, at 2 μM [ 3H]-glutamate, the uptake initial velocity showed a biphasic pattern, with a transient peak between 1 and 6 DIV, the maximum being reached at 2 DIV and a delayed regular increase from 8 to 23 DIV. The concentration-dependent curves were best fitted with two saturable sites high and low affinities, at both 2 and 10 DIV. To pharmacologically characterize the transient increased glutamate uptake activity, four uptake inhibitors, l- threo-3-hydroxy-aspartic acid (THA), l- trans-pyrrolidine-2,4-dicarboxylic acid ( l- trans-2,4-PDC), dihydrokainate (DHK), and dl- threo-β-benzyloxyaspartate (TBOA) were tested. THA, l- trans-2,4-PDC and dl-TBOA inhibited glutamate uptake both at 2 and 10 DIV, while the GLT-1 selective uptake inhibitor DHK neither strongly affected the uptake at 2, nor at 10 DIV. These data indicated that, besides the regular increase in the glial-dependent glutamate uptake activity, a transient high-affinity, DHK insensitive, glutamate transport activity in hippocampal neurons in culture is present. This latter activity could potentially be related to the transient expression of the glial GLAST transporter in neurons.

A transient increase in endogeneous erythropoietin levels after paediatric liver transplantation

We investigated whether liver transplantation affects endogeneous erythropoietin (EPO) synthesis. Serum EPO levels were measured before transplantation and during the peri-transplant period in ten consecutive paediatric patients who had received a liver allograft without recombinant EPO therapy. All patients were anaemic on post-operative day 1 (POD 1); however, the haemoglobin levels of three patients gradually increased and required phlebotomy on POD 5–9. The serum levels of EPO in all patients were within the normal range before surgery, but six of the ten patients had a transient increased level of EPO at 12–48 h after transplantation. A transient increase of endogeneous EPO following paediatric liver transplantation may be associated with extramedullary erythropoiesis in human liver grafts.

Changes in cartilage proteoglycan aggrecan after intra-articular injection of interleukin-1 in rabbits: studies of synovial fluid and articular cartilage.

To determine how acute but transient inflammation affects the cartilage proteoglycan aggrecan and the value of analyses of synovial fluid to study this. For 96 hours after a single intra-articular injection of rabbit knees with human interleukin-1 alpha (IL-1 alpha) or vehicle, articular cartilage and synovial fluid were examined using a putative indicator of aggrecan synthesis (aggrecan chondroitin sulphate epitope 846), immunoreactive keratan sulphate, and total glycosaminoglycan (GAG) content. Aggrecan extractability (with 0.5 M NaCl) followed by 4 M guanidine hydrochloride extraction permitted analyses of cartilage damage, total content and aggrecan heterogeneity. Aggrecan epitopes as well as GAG were assayed in synovial fluid. Changes were related to total joint leucocyte content in synovial fluid. At 10 ng, IL-1 alpha produced a transient increase in synovial fluid leucocytes at six hours and 24 hours. This accompanied a reduction in content and increased extractability of GAG, which was greatest in the tibial medial compartment of the knee. Further studies of this compartment showed no change in keratan sulphate epitope content, but a transient increase in extractability in 0.5 M NaCl. Epitope 846 content and extractability were unchanged. Total contents and extractability for GAG were inversely correlated in both controls and joints injected with IL-1 alpha. These changes were accompanied by transient increases in GAG, keratan sulphate epitope, and 846 content in synovial fluid. According to the aggrecan component measured, damage to the matrix of articular cartilage was sometimes reflected by a transient increased extractability and a net loss of aggrecan. There was always an increased release of GAG, and keratan sulphate, and 846 epitopes into synovial fluid. These studies show that changes in aggrecan epitopes and GAG in synovial fluid reflect changes in cartilage metabolism induced by acute transient inflammation.

Correlation between reactive sprouting and microtubule protein expression in epileptic hippocampus

Temporal lobe epilepsy in both human and rats is associated with a collateral sprouting of hippocampal mossy fibers (i.e. the axons of granule cells). This sprouting generates abnormal recurrent synaptic connections. We previously showed that in the experimental model of temporal lobe epilepsy induced by an intra-amygdaloid injection of kainate, the synaptic remodeling of mossy fibers was preceded by a transient increased expression of α-tubulin in granule cells. This suggests that an overproduction of tubulin polymers may be responsible, at least in part, for the elongation and side-branching of mossy fibers, which occurs 12–30 days after seizures. In the present study we show that this increased expression of α -tubulin is accompanied by an increased expression of the microtubule-associated proteins MAP2 and TAU. Thus, using in situ hybridization, we observe that MAP2 messenger RNA levels increased in granule cell bodies and dendrites from day 3 to two weeks after kainate treatment. This rise is associated with a concomitant transient increase of MAP2 immunoreactivity in the granule cell dendrites. TAU messenger RNA also increases in granule cell bodies, while TAU immunoreactivity increases in their axons, the mossy fibers. The time course of these changes parallels that of α-tubulin, and develops before and during the axonal mossy fiber sprouting. Since MAP2 and TAU are important for the initiation, elongation and stabilization of neuntes, we suggest that the overexpression of these proteins via the formation of microtubules may play an important role in the sprouting of mossy fibers in epileptic rats.

Calcium regulation of skeletal myogenesis. I. Cell content critical to myotube formation

Primary cultures of embryonic chick pectoral skeletal muscle were used to study calcium regulation of myoblast fusion to form multinucleated myotubes. Using atomic absorption spectrometry to measure total cellular calcium and the 45Ca-exchange method to determine free cellular Ca++, our data suggest that only the free cellular calcium changes significantly during development under conditions permissive for myotube formation (0.9 mM external Ca++). Increases in calcium uptake occurred before and toward the end of the period of fusion with the amount approximating 2 to 4 pmol per cell in mass cultures. If the medium [Ca++] is decreased to 0.04 mM, as determined with a calcium electrode, a fusion-block is produced and free cell Ca++ decreased 5- to 10-fold. Removal of the fusion-block by increasing medium [Ca++] results in a release of the fusion-block and an increase in cellular Ca++ to approximately 1 pmol per cell during fusion, and higher thereafter. Cation ionophore A23187 produced transient increases in cellular calcium and stimulated myoblast fusion and the final extent of myotube formation only when added at the onset of culture. Results suggest that transient increased calcium uptake alone is insufficient for fusion because critical cellular content in conjunction with permissive amounts of medium [Ca++] must exist. The latter suggests further that cell surface Ca++ was also critical.

Transient increase of NMDA-binding sites in human hippocampus during development

In the human hippocampus, the density of glutamate and N- methyl- d-aspartate (NMDA) binding sites follows during development a bell-shaped curve with a peak at 23–27 fetal weeks. We suggest that there is a transient increased density of NMDA binding sites during a restricted period of hippocampal development; this may play an important role in developmental plasticity.

The cell cycle and its relation to growth during pattern regulation in wing discs of Drosophila

In this paper we have examined the timing of growth-rate changes, of alterations in the cell cycle, and of the reestablishment of epithelial continuity during the early stages of regulative growth of imaginal wing discs cultured in vivo. Tissue organization was disrupted prior to culture, by dissociation, and centrifugally reaggregated pellets of cells were cultured in adult female flies. Significant increases in cell numbers were detectable during the first day of culture. Flow cytometric analysis of the DNA content of cells in reaggregates during culture indicated that during the first half-day of culture, a significant transient increase in the proportions of S-phase and post-S-phase cells occurred. Scanning electron microscopic examination of dissociated cells during culture confirmed that tissue reorganization began during the first day and was nearly complete by the end of the second day. During the second day of culture, when the growth rate was maximal, the proportions of pre-( G 1 ) and post-S-phase and mitotic ( G 2 M) cells resembled those of intact premetamorphic wing discs. In contrast to disrupted tissue, intact or minimally wounded wing discs showed practically no change in cell number during culture. However, with both disrupted and intact tissue, the proportion of G 1 cells increased significantly during the culture period so that by the fourth day of culture G 1 cells predominated. Under our conditions all implants grew extensively, but regeneration by cultured reaggregates formed from pure presumptive notum and pure presumptive distal wing fragments was observed in those implants which grew the most. Our results suggest that both DNA synthesis and transient increased proportions of 4C cells may occur as an early response to injury and that these may precede the onset of cell divisions even under conditions where growth is initiated early. Our observations also suggest that the onset of cell divisions, though it occurs well before the end of the first day of culture, may nonetheless be preceded by cellular contacts and intercellular communication.

Intra-articular knee joint temperature variations in response to cooling and heating of the skin in the cat.

AbstractThe intra‐articular temperature was measured in the knee joint of the cat during cooling and heating of the anteriomedial aspect of the thigh. Cooling produced a transient increase of the intra‐articular temperature before it began to fall, and rewarming gave a transient increased fall of the intra‐articular temperature before it began to rise. These paradoxical phenomena could be produced in the intact animals and in animals with partially denervated knee joints. In a flayed limb no paradoxical temperature phenomena could be produced, neither could they be set up in a limb deprived of its sympathetic outflow by unilateral lumbar sympathectomy. The blood pressure was found to increase and decrease transiently during cooling and heating respectively. The variations of the pressure occurred almost simultaneously with the paradoxical temperature phenomena in the joint. These blood pressure variations can, however, only be part of the explanation of the paradoxical effects seen, because cooling the intact limb which increases the blood pressure, was not found to produce the phenomenon in the contralateral sympathectomized side. The mechanisms behind the paradoxical phenomena are discussed and it is concluded that temperature variations as measure of bloodflow variations in response to cooling and heating can only be used when they vary in the opposite direction to the stimuli applied.