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Biomedical subjects

K C Lai

Publications and source records attributed to K C Lai.

78 records · Page 5Linked to original sources
PubMed1992

A comparison of two dual-energy X-ray absorptiometry systems for spinal bone mineral measurement.

Two dual-energy X-ray absorptiometry (DEXA) systems--the Hologic QDR-1000 and the Norland XR-26 bone densitometers--were evaluated in terms of precision, accuracy, linearity of response, X-ray exposure, and correlation of in vivo spinal measurements. In vitro precision and accuracy studies were performed using the Hologic anthropomorphic spine phantom; linearity of response was determined with increasing thicknesses of aluminum slabs and concentrations of Tums E-X in a constant-level water bath. Both systems were comparable in precision, achieving coefficients of variation (CVs) of less than 1% in bone mineral content (BMC, g), bone area (cm2), and bone mineral density (BMD, g/cm2). Both were accurate in their determination of BMC, bone area, and BMD with reference to the Hologic spine phantom. Both systems also showed good BMC and BMD linearity of response. Measured X-ray skin surface exposures for the Hologic and the Norland systems were 3.11 and 3.02 mR, respectively. In vivo spinal measurements (n = 65) on the systems were highly correlated (BMC: r = 0.993, SEE = 1.770 g; area: r = 0.984, SEE = 1.713 cm2; BMD: r = 0.990, SEE = 0.028 g/cm2). In conclusion, both systems are comparable in terms of precision, accuracy, linearity of response, and exposure efficiency.

Absorptiometry, Photon↗
PubMedDate not supplied

Gastric cytoprotection by amoxycillin in the rat.

Amoxycillin in combination with anti-ulcer agents has been shown to prolong duodenal ulcer remission. While this effect can be related to the eradication of Helicobacter pylori, it is not known if amoxycillin might possess cytoprotective properties. Protection against ethanol-induced gastric mucosal damage by intragastric instillation of amoxycillin suspension (prepared from capsule form) and solution (from injection form, 100% pure amoxycillin), and by intraperitoneal injection of amoxycillin solution was studied using an ex vivo gastric chamber in the rat. Intragastric and intraperitoneal administration of amoxycillin dose-dependently protected the rat gastric mucosa from damage by absolute ethanol. This protection was lost when the rats were pretreated with indomethacin. Gastric mucosal blood flow as measured by laser Doppler flowmetry and gastric acid output were unaffected by amoxycillin. Amoxycillin imparts gastric cytoprotection, and one possible mechanism is by the release of prostaglandins.

Amoxicillin↗
PubMedDate not supplied

One-stage thoracoscopic oesophagectomy: ligature intrathoracic stapled anastomosis.

Thoracoscopic oesophagectomy is usually performed in stages and intrathoracic oesophagogastric anastomosis often requires mini-thoracotomy or extension of the thoracoscopic incisions. This paper describes a new technique whereby such an operation could be completed in one stage and the need to extend the thoracoscopic incisions is obviated.

Adenocarcinoma↗
PubMedDate not supplied

Knot tying at flexible endoscopy.

Four new knotting techniques were developed for use at flexible endoscopy: (1) half hitches tied with knot-pusher, (2) thread-locking device, (3) self-tightening slip-knot, and (4) externally releasable knot. Remoteness from site of action, access through small-diameter orifice, and difficulty in applying lateral traction to tighten knots are problems met in knot tying at endoscopy. All four knotting techniques were studied in experiments on postmortem human stomachs and used for radio-telemetry studies and anti-reflux operations in survival studies in dogs using endoscopic sewing techniques. Half hitches tied at endoscopy with a knot-pusher were also used in human studies to treat esophageal reflux and secure pH radio-telemetry capsules for long-term measurements. Externally releasable knots were used to secure nasogastric tubes to the stomach of five patients for long-term nutrition. Knot tying is feasible at flexible endoscopy by a variety of new techniques. Endoscopically tied knots can be as secure as surgically hand-tied knots and have been used successfully in man.

Animals↗