Cellular and molecular signatures of motherhood in the adult and ageing rat brain.

Pregnancy is marked by robust changes, including brain changes to volume, structure, connectivity and neuroplasticity. Although some brain changes are restricted to pregnancy and the postpartum, others are long-lasting. Few studies have examined possible mechanisms of these changes or the effects of multiple pregnancies. We characterized various cellular and molecular signatures of parity (nulliparous, primiparous, biparous) in the rat hippocampus. We investigated density of neural stems cells (Sox2), microglia (Iba-1) and levels of a synaptic protein (PSD-95), cell signalling pathways, neuroinflammation, and the tryptophan-kynurenine (TRP-KYN) pathway, one week after weaning their pups from the last pregnancy (age of dam: seven months) and in middle-age (age of dam: 13 months). Parity increased PSD-95 levels in both age groups and prevented the age-related decrease in neural stem cell density observed in nulliparous rats. Biparity increased cell signalling phosphoproteins (pp70S6K, S6RP) and number of microglia in the dentate gyrus, regardless of age. Parity resulted in transient changes to the TRP-KYN system. Thus, previous parity has lasting effects on synaptic plasticity with fewer lasting effects on inflammation and cell signalling phosphoproteins in the whole hippocampus.

Effects of chronic oestradiol, progesterone and medroxyprogesterone acetate on hippocampal neurogenesis and adrenal mass in adult female rats.

Both natural oestrogens and progesterone influence synaptic plasticity and neurogenesis within the female hippocampus. However, less is known of the impact of synthetic hormones on hippocampal structure and function. There is some evidence that the administration of the synthetic progestin, medroxyprogesterone acetate (MPA) is not as beneficial as natural progesterone and can attenuate oestrogen-induced neuroprotection. Although the effects of oestradiol have been well studied, little is known about the effects of natural and synthetic progestins alone and in combination with oestradiol on adult neurogenesis in females. In the present study, we investigated the effects of chronic oestradiol, progesterone, MPA and the co-administration of each progestin with oestradiol on neurogenesis within the dentate gyrus of adult ovariectomised female rats. Twenty-four hours after a bromodeoxyuridine (BrdU; 200 mg/kg) injection, female rats were repeatedly administered either progesterone (1 or 4 mg), MPA (1 or 4 mg), oestradiol benzoate (EB), progesterone or MPA in combination with EB (10 µg), or vehicle for 21 days. Rats were perfused on day 22 and brain tissue was analysed for the number of BrdU-labelled and Ki67 (an endogenous marker of cell proliferation)-expressing cells. EB alone and MPA + EB significantly decreased neurogenesis and the number of surviving BrdU-labelled cells in the dorsal region of the dentate gyrus, independent of any effects on cell proliferation. Furthermore, MPA (1 and 4 mg) and MPA + EB treated animals had significantly lower adrenal/body mass ratios and reduced serum corticosterone (CORT) levels. By contrast, progesterone + EB treated animals had significantly higher adrenal/body mass ratios and 1 mg of progesterone, progesterone + EB, and EB significantly increased CORT levels. The results of the present study demonstrate that different progestins alone and in combination with oestradiol can differentially affect neurogenesis (via cell survival) and regulation of the hypothalamic-pituitary-adrenal axis. These findings have implications for women using hormone replacement therapies with MPA for both neuroprotection and stress-related disorders.

Different forms of oestrogen rapidly upregulate cell proliferation in the dentate gyrus of adult female rats.

Oestrogens are known to exert significant structural and functional effects in the hippocampus of adult rodents. The dentate gyrus of the hippocampus retains the ability to produce neurones throughout adulthood and 17beta-oestradiol has been shown to influence hippocampal neurogenesis in adult female rats. The effects of other oestrogens, such as oestrone and 17alpha-oestradiol, on neurogenesis have not been investigated. The present study aimed to investigate the effects of 17beta-oestradiol, oestradiol benzoate, oestrone, and 17alpha-oestradiol on cell proliferation in ovariectomised adult female rats at two different time points. Young ovariectomised female rats were injected with one of the oestrogens at one of three doses. In Experiment 1, rats were exposed to the hormone for 4 h and, in Experiment 2, rats were exposed to the hormone for 30 min prior to 5-bromo-2-deoxyuridine injection to label proliferating cells and their progeny. We found that young ovariectomised females responded with increased cell proliferation to most oestrogens, except oestradiol benzoate, after 30 min of exposure. However, administration of oestrogens for a longer time interval was ineffective at increasing cell proliferation. After 30 min, 17beta-oestradiol and oestrone increased cell proliferation at low (0.3 microg) and high (10 microg) doses, whereas 17alpha-oestradiol increased cell proliferation at medium (1 microg) and high doses. The results of the present study indicate that different oestrogens rapidly increase cell proliferation in a dose-dependent manner, possibly through a nonclassical, nongenomic mechanism. Future experiments should focus on further elucidating the specific pathways utilised by each oestrogen. These results have important therapeutic implications because it may be possible to use 17alpha-oestradiol and lower doses of oestrogens in hormone replacement therapies.

Both estrogen receptor alpha and estrogen receptor beta agonists enhance cell proliferation in the dentate gyrus of adult female rats.

This study investigated the involvement of estrogen receptors alpha and beta in estradiol-induced enhancement of hippocampal neurogenesis in the adult female rat. Subtype selective estrogen receptor agonists, propyl-pyrazole triol (estrogen receptor alpha agonist) and diarylpropionitrile (estrogen receptor beta agonist) were examined for each receptor's contribution, individual and cooperative, for estradiol-enhanced hippocampal cell proliferation. Estradiol increases hippocampal cell proliferation within 4 h [Ormerod BK, Lee TT, Galea LA (2003) Estradiol initially enhances but subsequently suppresses (via adrenal steroids) granule cell proliferation in the dentate gyrus of adult female rats. J Neurobiol 55:247-260]. Therefore, animals received s.c. injections of estradiol (10 microg), propyl-pyrazole triol and diarylpropionitrile alone (1.25, 2.5, 5.0 mg/0.1 ml dimethylsulfoxide) or in combination (2.5 mg propyl-pyrazole triol+2.5 mg diarylpropionitrile/0.1 ml dimethylsulfoxide) and 4 h later received an i.p. injection of the cell synthesis marker, bromodeoxyuridine (200 mg/kg). Diarylpropionitrile enhanced cell proliferation at all three administered doses (1.25 mg, P<0.008; 2.5 mg, P<0.003; 5 mg, P<0.005), whereas propyl-pyrazole triol significantly increased cell proliferation (P<0.0002) only at the dose of 2.5 mg. Our results demonstrate both estrogen receptor alpha and estrogen receptor beta are individually involved in estradiol-enhanced cell proliferation. Furthermore both estrogen receptor alpha and estrogen receptor beta mRNA was found co-localized with Ki-67 expression in the hippocampus albeit at low levels, indicating a potential direct influence of each receptor subtype on progenitor cells and their progeny. Dual receptor activation resulted in reduced levels of cell proliferation, supporting previous studies suggesting that estrogen receptor alpha and estrogen receptor beta may modulate each other's activity. Our results also suggest that a component of estrogen receptor-regulated cell proliferation may take place through alternative ligand and/or cell-signaling mechanisms.

Leiomyosarcoma presenting as a mandibular gingival swelling: a case report.

We report a case of primary low-grade leiomyosarcoma of the mandible in an otherwise healthy young woman. The neoplasm presented as a painful, pericoronal gingival swelling that mimicked an acute periodontal infection. It was managed accordingly, with curettage, debridement, and antibiotics. When the lesion failed to respond to this treatment approach, a biopsy was performed. Microscopy revealed a malignant mesenchymal neoplasm which, on immunohistochemistry analysis, demonstrated reactivity for smooth muscle actin (SMA) and vimentin. This established the diagnosis of leiomyosarcoma; subsequently, an en bloc resection of mandibular bone and overlying soft tissue was performed. Close follow-up for over 10 years has revealed no evidence of recurrent or metastatic disease. Since the patient was taking oral contraceptives prior to the onset of the lesion, a possible link between estrogen and smooth muscle tumors is considered.

Neurologic emergencies.

Neurologic emergencies are rare, and they usually occur in easily identifiable patients, provided that a thorough medical history has been previously obtained. Rare as these may be, however, they occur without warning and are potentially life threatening. Consequently, the dentist should be prepared by virtue of knowledge of the pathophysiology and therapy and by formal training and certification in basic life support.

Attenuation of anxiety in ambulatory oral surgery patients with oral triazolam.

The purpose of this investigation was to determine if the preoperative administration of an oral anxiolytic agent (triazolam) is beneficial in reducing the cardiovascular response to stress and anxiety. Twelve consecutive patients, six who received the drug and six who received a placebo, were monitored from the night before surgery at home until the morning with a Holter monitor. On presentation for surgery, levels of anxiety as well as heart rate and presence of cardiac arrhythmias were determined for the two groups. Patients who received the study medication had an anxiety level on the day of surgery similar to that recorded at an earlier consultation visit, whereas the placebo group showed a tendency toward an increase in anxiety on the day of surgery. There was a significant difference for resting heart rate between the two groups at various intervals associated with the preparation for the surgery. There were no complications related to the medication and, therefore, on the basis of this study, it appears that the administration of an oral anxiolytic agent prior to the patient presenting for surgery is beneficial in reducing the stress and anxiety associated with the operation as well as in reducing some of the cardiac manifestations of this stress.

Peripheral nerve injury during anesthesia.

A case is presented where a peripheral nerve injury occurred due to the pressure of a restraint buckle causing a postoperative motor and sensory deficit. Because these are iatrogenic injuries it is useful to review the mechanism of injury and means of prevention.

Accidental intra-arterial injection.

The potential for an accidental intra-arterial injection is present whenever an intravenous route of drug administration is used. Because of the serious nature of the morbidity associated with this iatrogenic injury, and its preventability, this article is presented to update the available information on the etiology, diagnosis, treatment, and prevention of this problem.

Changes in bone strength after augmentation with hydroxylapatite or hydroxylapatite/bone.

Adult, male New Zealand white rabbits had one humerus augmented with hydroxylapatite (HA) and one femur augmented with hydroxylapatite and autogenous, cortico-cancellous bone (HA-B). Contralateral bones were not augmented and used for controls. After periods of six and 16 weeks the animals were killed and the load sustained by the test and control bones at fracture was determined using three point loading. A significant increase in the load at fracture was noted in the bones augmented with either HA or HA-B.

The syndrome of inappropriate secretion of antidiuretic hormone in the maxillofacial trauma patient.

The maxillofacial trauma patient whose neurologic status undergoes a rapid and serious deterioration may have a severe hyponatremia secondary to the inappropriate secretion of antidiuretic hormone (SIADH). Other causes of hyponatremia must be ruled out, especially posttraumatic cerebral salt wasting, which necessitates a different mode of therapy. A case of SIADH is reported, and the work-up and differential diagnosis of posttraumatic hyponatremia are discussed.

Use of the electrosurgical knife and topical thrombin for hemostasis in split-thickness skin graft vestibuloplasty.

The use of electrocautery and topical thrombin at the donor and recipient sites has decreased most of the oozing normally present in skin graft vestibuloplasty procedures. It has effectively reduced operating room time, has significantly reduced post-operative morbidity, and has shortened both hospital stay and recovery time for the patient.

Septicemia secondary to administration of a contaminated intravenous fluid.

The clinical entities of bacterial contamination, septicemia, and septic shock have been discussed, and an unusual case of septic shock has been presented. The associated risks of intravenous delivery of drugs or fluids are stressed.