Traumatic hypopituitarism associated with bitemporal hemianopia in a prepuberal child

Metformin increases PDH and suppresses HIF-1α under hypoxic conditions and induces cell death in oral squamous cell carcinoma

Background

Metformin is a biguanide, belonging to the oral hypoglycemic agents and is a widely used in the treatment of type 2 diabetes. Evidence indicate that Metformin inhibits cell proliferation in several human cancers and inhibits the Warburg phenomenon in tumor cells.

Results

Low PDH levels were observed in OSCC, and Metformin promotes an increase in PDH levels in hypoxic conditions. Metformin also reduced HIF-1α mRNA and protein levels. Metformin demonstrated antiproliferative effects, inhibited migration, increased the number of apoptotic cells and increased the transcription of caspase 3.

Objective

The present study aims to explore the effects of Metformin in hypoxic conditions. Specifically, we focused on pyruvate dehydrogenase (PDH), (hypoxia-inducible factor 1α) HIF-1α levels and the oral squamous cell carcinoma (OSCC) cell phenotype. Additionally, we also investigated a theoretical consequence of Metformin treatment.

Methods

PDH levels in patients with OSCC and oral dysplasia were evaluated. Metformin was administered in vitro to test the effect of Metformin under hypoxic conditions. The results were complemented by Bioinformatics analyses.

Conclusions

In conclusion, our current findings show that Metformin reduces HIF-1α gene expression and increases PDH expression. Metformin inhibits cell proliferation and migration in the OSCC cell line model. Additionally, Metformin enhances the number of apoptotic cells and caspase 3 levels. Interestingly enough, Metformin did not increase the mutant p53 levels under hypoxic conditions.

Damage to intracranial optic pathways in fatal closed head injury in man

Head injury is a leading cause of visual impairment. This is partly due to direct trauma to the eye and optic nerve but much of the damage involves the intracranial optic pathways. We have studied the frequency, distribution and nature of the intracranial lesions of the optic pathways at autopsy in 45 cases of severe closed head injury, and examined the correlation between these post-mortem lesions and the ante-mortem clinical findings. Twenty-four of the patients had been involved in road traffic accidents. The ages ranged from 9 to 88 years (mean 46.4), the Glasgow Coma Score (GCS) on admission ranged from 3 to 15 (mean 5), and the survival time after injury from 2.5 h to15 days (mean 3.3 days). Skull fractures were present in 75.6% of the cases. Histological assessment included the use of immunohistochemistry for beta-amyloid precursor protein (beta-APP) and the microglial marker CD68. Axonal injury of varying severity was demonstrable in all cases, and in 39 (87%) the optic chiasm, tracts or radiations were involved, usually in more than one region. The severity of axonal injury was mild in 11 (24%), moderate in 9 (20%) and severe in 19 (42%) cases. The optic radiation at the level of the trigone of the lateral ventricle was particularly frequently and severely affected. The least affected parts of the intracranial optic pathways were the optic chiasm and the posterior segment of the optic nerve. The severity of injury to the optic pathways did not always reflect severity of axonal injury elsewhere in the brain and correlated poorly with the type of trauma (high- or low-velocity), presence of skull fractures or evidence of raised intracranial pressure (ICP). Of the 39 patients who survived more than 6 h, histological evidence of ischaemic injury to the primary optic cortex was present in 26 (67%) and was severe in 12. We conclude that the visual pathways are affected in a high proportion of patients with fatal closed head injury, nerve fibres in the optic radiations being particularly vulnerable. The findings suggest that damage to the posterior parts of the optic pathways may be under-diagnosed among patients with head injury.

Spontaneous recovery from post-traumatic hypopituitarism

Recovery of the pituitary function from post-traumatic hypopituitarism is an exceptional event. We present the case of a 32 year-old man who was involved in a road traffic accident in which he suffered a severe head injury. Four days following the trauma the patient developed post-traumatic central diabetes insipidus and desmopressin was started. At discharge of the intensive care unit, the patient was referred to us for endocrine assessment. Three months after the head injury, the hormonal evaluation of the hypothalamic-pituitary axis by means of insulin stress test with the simultaneous administration of TRH and GnRH resulted in reduced responses of GH, cortisol, TSH, FSH, and LH with low baseline serum concentrations of free T4 and testosterone. Both serum basal and stimulated PRL concentrations were normal. Magnetic resonance imaging demonstrated deformity of the sella turcica with displacement of the pituitary gland by a post-traumatic retention cyst. A new evaluation of the pituitary function performed 6 months after the trauma showed spontaneous recovery of the gonadal, thyroid and adrenal function. However, GH response was reduced both to insulin-induced hypoglycemia, clonidine and GHRH tests. Presence of normal serum PRL levels, normal PRL response to TRH and reduced GH responses to pituitary and hypothalamic stimuli suggests both hypothalamic and pituitary damage. The present case shows an unusual case of partial spontaneous resolution of a post-traumatic hypopituitarism. Based on this clinical observation we recommend periodic evaluation of the pituitary function in these kind of patients.

Visual abnormalities with multiple trauma

The diversity of pathogenetic mechanisms involved in posttraumatic visual impairment was reviewed in a study of the hospital records of 24 patients admitted with multiple injuries. Most major visual abnormalities occurred in young people (average age 33 years) who presented with a wide range of overall severity of injury (injury severity score 13-47) and involvement of the central nervous system (Glasgow coma scale 5-15). Bilateral or monocular blindness developed in 63% of patients. Seventy percent of the injuries involved the anterior visual pathways with damage to the optic nerve alone accounting for 35%. Fractures of the sphenoid bone, particularly of the body, accompanied optic nerve and chiasmal injuries and some cases of traumatic carotid-cavernous fistulas. Pathogenetic mechanisms varied according to the site of injury and included vitreous hemorrhage and optic atrophy secondary to raised intracranial pressure, retinal hypoxia from carotid-cavernous fistulas, shearing and compression injuries of the optic nerve, traumatic chiasmal syndrome, temporoparietal and occipital contusions, and transtentorial herniation with occipital infarction. Visual abnormalities varied in severity from moderately reduced visual acuity and diverse hemianopias and scotomas to blindness. The incidence of posttraumatic residual visual abnormalities is likely to increase in the wake of improved acute care of the traumatized victim.

Traumatic chiasmal syndrome associated with pneumocephalus and sellar fracture

A 50-year-old man sustained severe head injury, including a brief loss of consciousness, in an automobile accident. Skull X-ray films disclosed a fracture of the right superior orbit. Computed tomography demonstrated pneumocephalus and extension of the fracture into the sella turcica. Perimetric testing disclosed a bitemporal hemianopia along the vertical meridian. Visual acuity was 6/6 (20/20) in both eyes. Right macular sparing and left macular splitting were demonstrated by Amsler grid analysis as well as by the patient's description of target grids projected onto his maculas. Diplopia was attributed to direct grids projected onto his maculas. Diplopia was attributed to direct injury of the right superior rectus muscle and to the effect of bitemporal field loss. There was no evidence of pituitary dysfunction. No treatment of the patient's visual loss was undertaken. A six-month follow-up examination disclosed no change in the patient's visual field abnormalities.