Structural changes in plastids of developing Splachnum ampullaceum sporophytes and relationship to odour production.

Many mosses of the family Splachnaceae are entomophilous and rely on flies for spore dispersal. Splachnum ampullaceum produces a yellow- or pink-coloured hypophysis that releases volatile compounds, attracting flies to the mature moss. The biosynthetic sources of the visual and aromatic cues within the hypophysis have not been identified, and may be either symbiotic cyanobacteria or chromoplasts that break down lipids into volatile compounds. Here, we used transmission electron microscopy and gas chromatography-mass spectrometry (GC-MS) to investigate the sources of these attractants, focusing on different tissues and stages of maturation. Microscopy revealed an abundance of plastids within the hypophysis, while no symbiotic bacteria were observed. During plant maturation, plastids differentiated from amyloplasts with large starch granules to photosynthetic chloroplasts and finally to chromoplasts with lipid accumulations. We used GC-MS to identify over 50 volatile organic compounds from mature sporophytes including short-chain oxygenated compounds, unsaturated irregular terpenoids, fatty acid-derived 6- and 8-carbon alcohols and ketones, and the aromatic compounds acetophenone and p-cresol. The hypophysis showed localised production of pungent volatiles, mainly short-chain fermentation compounds and p-cresol. Some of these volatiles have been shown to be produced from lipid oxidase degradation of linolenic acid within chromoplasts. However, other compounds (such as cyclohexanecarboxylic acid esters) may have a microbial origin. Further investigation is necessary to identify the origin of fly attractants in these mosses.

Medial prefrontal cortex activity can disrupt the expression of stress response habituation.

Recent findings suggest that the expression of hypothalamic-pituitary-adrenal (HPA) axis stress response adaptation in rats depends on top-down neural control. We therefore examined whether the medial prefrontal cortex (mPFC) modulates expression of stress response habituation. We transiently suppressed (muscimol microinfusion) or stimulated (picrotoxin microinfusion) mPFC neural activity in rats and studied the consequence on the first time response to psychological stress (restraint) or separately on the development and expression of habituation to repeated restraint. We monitored both the hormonal (corticosterone) and neural (forebrain c-fos mRNA) response to stress. Inactivation of the mPFC had no effect on the HPA-axis response to first time restraint, however increased mPFC activity attenuated stress-induced HPA-axis activity. In a three day repeated restraint stress regimen, inactivation of the mPFC on days 1 and 2, but not day 3, prevented the expression of HPA-axis hormone response habituation. In these same rats, the mPFC activity on day 3 interfered with the expression of c-fos mRNA habituation selectively within the mPFC, lateral septum and hypothalamic paraventricular nucleus. In contrast, inactivation of the mPFC only on day 3, or on all 3 days did not interfere with the expression of habituation. We conclude that the mPFC can permit or disrupt expression of HPA-axis stress response habituation, and this control depends on alteration of neural activity within select brain regions. A possible implication of these findings is that the dysregulation of PFC activity associated with depression and post-traumatic stress disorder may contribute to impaired expression of stress-response adaptation and consequently exacerbation of those disorders.

Tuberculous osteomyelitis of the mandible: a case report.

Osteomyelitis of jaws caused by infection with Mycobacterium tuberculosis is uncommon, especially in children. We present a case of tuberculous osteomyelitis in a young child. Its clinical presentation, with features similar to a dento-alveolar abscess, underline the importance of considering it in the differential diagnosis of jaw lesions. We discuss of the diagnostic techniques, management and preventive measures, and stress the importance of history taking during clinical examination.

Oral myiasis: a case report.

Oral myiasis is a rare condition caused by the invasion of tissues by larvae of flies. A case of gingival myiasis is presented in a 12-year-old boy with learning disability. The patient was unaware of the lesion, although it produced a swelling partially covering the teeth. The lesion was treated with ether, which forced the larvae out, and irrigated with warm saline solution. Follow-up examination revealed complete subsidence and healing of the lesion.

Idiopathic gingival fibromatosis associated with mild hypertrichosis.

A case of gingival fibromatosis with hypertrichosis is reported in a 10 year old girl. The condition is a syndrome and presents as a triad of gingival fibromatosis, hypertrichosis and mental retardation. Following surgical management, no recurrence was seen in the immediate post-surgical period. Even if recurrence occurs excision is recommended as the psychological benefits resulting from cosmetic improvement outweigh the danger of recurrence.

Angiomyoma of the mandible: a case report.

A rare case of intrabony angiomyoma affecting the mandible is presented. The patient was 25 years old male who complained of swelling and pain in the posterior segment of his lower jaw. Histopathologically diagnosed angiomyoma is discussed with emphasis on the pathogenesis in the present case. Literature concerning the lesion is reviewed. In the present paper we report a case of angiomyoma affecting the mandible. Angiomyomas are also known as vascular leiomyomas which commonly occur in the wrist and ankle region. They are painful tumours as was also evident in our case. These tumours are characterized histopathologically by convuluted thick walled vessels associated with bundles of well differentiated smooth muscle elements. They rarely affect the oral cavity. Therefore our case is one of the few cases affecting the oral cavity as reported earlier. Tumours of the smooth muscle cells which form involuntary muscle are known as leiomyomas. These commonly affect the alimentary tract. They are rarely found to affect the oral cavity.