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Biomedical subjects

K Dhital

Publications and source records attributed to K Dhital.

8 recordsLinked to original sources
PubMed2004

Midterm results of the Ross procedure.

OBJECTIVE: The lack of durable bioprosthetic valves and the inherent risks associated with anticoagulation for mechanical valves have led to the continued use of the Ross procedure, particularly in the pediatric population. METHODS: We have reviewed our mid-term results retrospectively, following the Ross operation in both pediatric and adult groups. RESULTS: Over a 11-year period from August 1991 to August 2002, 60 patients underwent the Ross procedure. The median age was 15 years (6-804 months), of which 63% were males and 55% were under the age of 20 years. The main indications were: aortic stenosis in 47 patients; aortic insufficiency in 6 patients; and mixed aortic valve disease in 28 patients. Fifteen patients had previously undergone balloon dilatation of the aortic valve, 4 had open valvotomy and 3 had both valvuloplasty procedures. The pulmonary autograft was implanted as a sub-coronary implant until 1995 (30%) after which time it was implanted using a partial inclusion cylinder technique (70%). There have been no deaths reported in this series. Over a median follow-up period of 59 months (2-122 months), there have been four re-operations for repair of autograft leak, and 2 adult patients have had autograft replacements. CONCLUSIONS: Despite the increased technical complexity, the Ross procedure can be performed safely in both paediatric and adult populations with satisfactory medium term results.

Adolescent↗
PubMed2003

Gerbode's defect resulting from infective endocarditis.

We present a report of a Gerbode's defect (left ventricular-right atrial communication) resulting from bacterial endocarditis in a 63-year-old man. Also presented is a brief overview of the literature and a possible preoperative echocardiographic diagnostic criterion relating to this unusual condition.

Aortic Valve Insufficiency↗
PubMed2000

[(18)F]Fluorodeoxyglucose positron emission tomography and its prognostic value in lung cancer.

OBJECTIVE: Positron emission tomography (PET) is being increasingly used as an accurate and non-invasive modality in diagnosis, staging and post-therapy assessment in patients with lung cancer. In this study, we examine whether the uptake of [(18)F]fluorodeoxyglucose (FDG), a marker of increased glucose metabolism in neoplastic cells, is of prognostic value in patients with primary lung cancer. METHODS: We have retrospectively analyzed 77 patients (mean age, 63. 0 years; male/female ratio, 53:24) with primary lung cancers who underwent whole body and localized thoracic PET as part of their diagnostic and staging procedures prior to consideration of surgical resection. The standardized uptake value (SUV) of injected FDG for each primary lesion was correlated with tumour histology and the patient's clinical outcome. RESULTS: A SUV of 20 or greater was found to be of significant prognostic value. The chance of survival (with 95% confidence intervals (CI)) at 12 months post-surgery for the various SUV groups was as follows: 75.2% (59.6-85.5) for SUV<10; 67.5% (29.0-88.2) for SUV 10-<12; 63.6% (29.7-84.5) for SUV 12-<15; 66.7% (19.5-90.4) for SUV 15-<20; 16.7% (0.01-0.52) for SUV>20. A SUV of 20 or more is associated with a 4.66 times increase in hazard, compared with lower levels of SUV. We found no significant correlation between tumour histology and SUV. CONCLUSION: We have previously reported on the significant advantages of PET in the staging and surgical care of patients with lung cancer. The present study adds further support for an additional prognostic role for PET in the management of thoracic malignancy as determined by the amount of labelled-FDG taken up by the primary lesion.

Adult↗
PubMed1998

Fifth-year hemodynamic performance of the prima stentless aortic valve.

BACKGROUND: The medium-term hemodynamic performance of stentless valves has not been widely reported, particularly in comparison with in vitro studies. Therefore, we have assessed prospectively the hemodynamics of the Edwards Prima valve in its fifth year after implantation in the aortic position, and compared the results with those at 1 month after implantation and also with in vitro data. METHODS: Thirty-five patients (age, 77 +/- 6 years; 19 men) were prospectively studied by Doppler echocardiography at 1 month and 52 +/- 8 months after implantation of a Prima stentless valve. Valve hemodynamics were assessed by measuring the mean pressure gradient, mean valve resistance, and effective orifice area. Left ventricular systolic function was quantified by ejection fraction, the degree of hypertrophy by ventricular mass index, and the ratio of ventricular wall thickness to cavity radius as a measure of ventricular geometry. RESULTS: With a mean valve size of 24.6 +/- 2.2 mm in the fifth year after implantation, the mean pressure gradient was 6.2 +/- 3.5 mm Hg, the mean valve resistance, 29 +/- 16 dyne x s(-1) x cm(-5)), and the effective orifice area was 2.05 +/- 0.50 cm2. Compared with 1 month after operation, there was a 47% decrease in mean valve resistance (p = 0.002) and a 39% increase in effective orifice area (p = 0.001). Furthermore, both effective orifice area and mean valve resistance in the fifth year did not differ from their in vitro counterparts, whereas the left ventricular ejection fraction (0.64 +/- 0.14), the left ventricular mass index (119 +/- 49 g/m2), and the ratio of ventricular wall thickness to cavity radius (0.44 +/- 0.13) were within the normal range. CONCLUSIONS: This study suggests that the Prima valve is a reliable stentless aortic bioprosthesis. This is supported by a favorable medium-term clinical outcome, durable hemodynamic performance, and normal mean values of left ventricular ejection fraction and mass index in the fifth year after implantation.

Aged↗
PubMed1990

Studies of vasoactive intestinal polypeptide expression in injured peripheral neurons using capsaicin, sympathectomy and mf mutant rats.

The increased expression of vasoactive intestinal polypeptide (VIP) in injured peripheral neurons was studied. In contrast to substance P, there was a marked increase, and maintained fast axonal transport, of VIP in rat sciatic nerve after peripheral axotomy. Local capsaicin application to the nerve trunk failed to inhibit the injury-induced VIP increase, and capsaicin even increased VIP levels when applied locally to uninjured nerves. Pharmacological sympathectomy showed that some of the peripheral VIP increase may occur in post-ganglionic sympathetic fibres. The VIP increase after injury appeared unaffected in the mf mutant rat, in spite of its loss of lumbar dorsal root ganglion cells. VIP-staining fibres in the epi- and peri-neurium and perivascular plexuses of sciatic nerve showed an increase in number in parallel with the changes of the nerve VIP content. These findings suggest that sensory and sympathetic nerve fibres expressing VIP after injury play a role in the regulation of blood flow to nerves, and in the pathophysiological processes in nerve and dorsal spinal cord which follow peripheral nerve injury.

Animals↗
PubMed1986

Adrenergic innervation of vasa and nervi nervorum of optic, sciatic, vagus and sympathetic nerve trunks in normal and streptozotocin-diabetic rats.

Adrenergic nerves were studied in nervi nervorum and perivascular nerve plexus of vasa nervorum in whole-mount nerve sheath preparations of optic, sciatic and vagus nerves and in the paravertebral sympathetic chain in normal and streptozotocin-treated diabetic rats. A substantial or complete loss of fluorescent adrenergic fibres around blood vessels in the optic nerves was observed 8 weeks after induction of diabetes. This was in marked contrast to the increase in perivascular adrenergic fibres in the sciatic, vagus and sympathetic chain nerve trunks of the same animals at the same time. Assays of noradrenaline levels in whole nerve segments also showed that they were not biochemically detectable in the optic nerves but were significantly higher in the vagus of diabetic animals (P less than 0.05). There was also an increase in numbers of mast cells in the vicinity of vasa nervorum of diabetic nerves.

Adrenergic Fibers↗