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Biomedical subjects

K Siu

Publications and source records attributed to K Siu.

17 recordsLinked to original sources
PubMed2006

Wavelet-based feature extraction applied to small-angle x-ray scattering patterns from breast tissue: a tool for differentiating between tissue types.

This paper reports on the application of wavelet decomposition to small-angle x-ray scattering (SAXS) patterns from human breast tissue produced by a synchrotron source. The pixel intensities of SAXS patterns of normal, benign and malignant tissue types were transformed into wavelet coefficients. Statistical analysis found significant differences between the wavelet coefficients describing the patterns produced by different tissue types. These differences were then correlated with position in the image and have been linked to the supra-molecular structural changes that occur in breast tissue in the presence of disease. Specifically, results indicate that there are significant differences between healthy and diseased tissues in the wavelet coefficients that describe the peaks produced by the axial d-spacing of collagen. These differences suggest that a useful classification tool could be based upon the spectral information within the axial peaks.

Algorithms↗
PubMed2004

Subarachnoid haemorrhage due to a dissecting aneurysm of the anterior cerebral artery: a case report.

Dissecting aneurysms of the intracranial carotid circulation are becoming increasingly recognised as a cause of subarachnoid haemorrhage. We present a case where SAH caused by anterior cerebral artery dissection was diagnosed on a repeat angiogram and successfully treated by surgical trapping. Diagnosis may be difficult as angiographic signs may be subtle and variable. Accurate diagnosis and prompt treatment is important, as the re-bleed rate is high.

Adult↗
PubMed2001

Acute effects of sldenafil ctrate (Viagra) on intraocular pressure in open-angle glaucoma.

PURPOSE: To assess the acute effects of sildenafil citrate (VIAGRA) on the intraocular pressure (IOP) of patients with chronic open-angle glaucoma. DESIGN: This was a double-blind, randomized, placebo-controlled, crossover study, in which 15 patients received a single oral dose of sildenafil 100 mg or matching placebo on two separate occasions. METHODS: Fifteen subjects aged 63 +/- 14 years (mean +/- SD) with bilateral chronic open-angle glaucoma were administered a single oral dose of sildenafil 100 mg or matching placebo on two separate occasions at least 3 days apart. IOP was measured in both eyes by Goldmann ap-planation tonometry at baseline and then at 1-5 hours after dosing. Brachial artery systolic and diastolic blood pressures were determined by sphygmomanometry, and heart rate was also monitored at baseline and 1-5 hours after dosing. RESULTS: Compared with placebo, no statistically or clinically significant change in IOP was detected after a single dose of sildenafil 100 mg (P =.20). Moreover, no significant change in mean systemic blood pressure (P =.12) or heart rate (P =.72) was detected after treatment with sildenafil. CONCLUSION: At the maximum therapeutic dose of 100 mg, sildenafil did not produce any significant acute change in IOP in men with chronic open-angle glaucoma. This information is of importance for patients with glaucoma receiving sildenafil for treatment of erectile dysfunction.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1991

Intraventricular neurocytoma, a recently recognized pathological entity: report of two cases and review of the literature.

Neurocytoma has only recently been recognized as a distinct pathological entity. Previously a rare tumor, it is now being recognized with increasing frequency. It typically presents in an intraventricular location in young adults. Many neurocytomas were originally diagnosed by light microscopy as oligodendrogliomas. More recently they have been shown to have ultrastructural and immunohistochemical features of neuronal differentiation. This paper presents two cases of intraventricular neurocytomas and reviews the recent literature.

Adult↗
PubMed1990

Temporal bone meningiomas.

Meningiomas should be considered in the differential diagnosis of space-occupying lesions of the temporal bone. Five cases of meningiomas of the temporal bone are described and the literature reviewed. These tumours may stimulate Schwannomas and glomus tumours in their presentation and radiological findings. The tumours were managed by combining standard neurosurgical approaches with temporal bone and skull base techniques.

Adolescent↗
PubMed1989

Ruptured intracranial aneurysms: a 12-month prospective study.

A prospective study was undertaken of all cases of ruptured intracranial aneurysms that presented to Monash Medical Centre's neurosurgical service over a 12-month period. Forty-seven patients had proved aneurysmal subarachnoid haemorrhages. The management mortality rate over all was 23.4%. Forty patients underwent definitive treatment by craniotomy and clipping of the aneurysm; the operative mortality rate was 12.5%. Excellent results were obtained in all 22 patients whose clinical grade was good on the day of surgery; half these patients underwent operation within 72 hours of the episode. Sixty per cent of all patients were discharged from hospital without any neurological deficit; virtually all the remaining patients' morbidity and mortality were attributable to aneurysmal rebleeding and cerebral vasospasm. Early surgery for aneurysms has been the trend in North America, Europe and Japan and the results that were obtained in this study support early surgery in patients with a good clinical grade; further experience is needed to establish the optimal timing of surgery in patients with a worse clinical grade.

Adolescent↗
PubMed1989

Cerebral deposits of carcinoid tumour.

This report details a most unusual case of cystic cerebral metastasis. The patient developed symptoms due to carcinoid deposits in the brain. The clinical course has been protracted and the primary source of the carcinoid tumour remains unknown.

Brain↗
PubMed1980

Vascular compression: cause of trigeminal neuralgia.

Fifty patients with trigeminal neuralgia have been operated upon, and the site of origin of the fifth nerve from the pons has been explored. Forty-four of these patients were demonstrated to have vascular compression at this point, and relief of the vascular compression resulted in pain relief in all of these patients, although two patients experienced some recurrence of pain. The maximum follow-up period is now six years. It is considered that the most common cause of trigeminal neuralgia is vascular compression of the fifth nerve at the nerve root entry zone.

Arteries↗
PubMed1976

Melanoma of the pituitary. Case report.

A case is described in which a pigmented tumor occupied the pituitary fossa with a large suprasellar extension. Its histological and ultrastructural appearances resembled those of a melanoma. The origin of the tumor is discussed with particular reference to Rathke's pouch.

Humans↗
PubMed1975

Chronic inflammatory lesions of the sphenoid sinus.

A case of chronic inflammation of the sphenoidal sinus is presented. The intermittent and relapsing nature of the condition is emphasized. Its association with hypopituitarism is distinctly uncommon. The surgical management of the case is discussed.

Chronic Disease↗
PubMedDate not supplied

Primary intraventricular hemorrhage in adults.

Five adults with primary intraventricular hemorrhage are described. The presenting features included headache, confusion and drowsiness. Focal neurological signs were minimal or absent. All five had a history of hypertension, three patients had bilateral internal carotid occlusion at its origin, one had unilateral occlusion of the left internal carotid artery with severe stenosis of the contralateral siphon. Unilateral occlusion of the middle cerebral artery were present in the fifth patient. Pathological examination of the brain from one patient showed the presence of severe hemorrhagic "lacunar" infarcts adjacent to the left lateral ventricle, one showing direct continuity of blood in the lacune with the massive intraventricular hematoma. We hypothesize that such a finding illustrates one possible mechanism for this unusual type of hemorrhage. Patients with longstanding hypertension and severe occlusive disease of the internal carotid arteries may be predisposed to this unusual complication.

Cerebral Angiography↗
PubMedDate not supplied

An unusual cranial injury caused by an industrial nail-gun.

An unusual case of an industrial nail-gun injury is presented. A 36-year-old man was struck in the back of his neck by a nail, which was fired from a high velocity Ramset nail-gun. The nail passed through the foramen magnum to lodge in front of the brainstem. In spite of the close proximity of the nail's trajectory to the upper cervical spinal cord and the brain stem, no major neurological damage resulted. The nail was removed successfully the following day. This case illustrates the potential for serious injury from nail-guns.

Accidents, Occupational↗