Biomedical subjects

K K Martin

Publications and source records attributed to K K Martin.

5 recordsLinked to original sources

PubMed1999

Modeling surgical expertise for motor skill acquisition.

BACKGROUND: This work is part of an ongoing effort to introduce an innovative medical teaching technique to assist the efficient acquisition of surgical hand skills required to perform an inguinal hernia repair with a McVay technique. The purpose was to determine the effect of expert cognitive modeling, auditory elaboration, and split-screen video analysis on the surgical hand movements required while performing inguinal hernia surgery on cadavers. PURPOSE: Six surgical residents were videotaped performing a McVay procedure inguinal hernia in a pretest-posttest control group design. The experimental group received expert cognitive modeling, auditory elaboration, and split-screen analysis after the pretest. RESULTS: A distinct advantage for surgical instrument control and manipulation was found for the experimental group on the posttest surgeries. Less time was required to perform the operation, and more purposeful movements were exhibited by the experimental group. CONCLUSION: The treatment condition favored mindfulness learning of the McVay technique for an inguinal hernia repair.

Cadaver↗

PubMed1995

Sustained hyperhydration with glycerol ingestion.

Heavy exercise lasting more than three hours tends to result in dehydration, as the fluid intake is less than fluid loss by sweat and urine. Dehydration as small as one percent of body weight has been reported to decrease work capacity. In present and previous studies insensible water loss and sweat are assumed to be the same in both control and experimental conditions. Fluid intake less urine volume is utilized as an indicator of euhydration, hypohydration, or hyperhydration. Previous studies involving glycerol intake describe hyperhydration for 4.5 to 8 hours. The objective of this study was to keep subjects hyperhydrated (retention of water) for 32 or 49 hours. The experimental protocol involved ingestion of a large volume of fluid (39.2 or 51.1 ml/kg/d) with glycerol (2.9 to 3.1 g/kg/d) and without glycerol. In both Series I (49 h) and Series II (32 h) experiments, the intake of glycerol resulted in smaller urine volumes. This study demonstrates it is possible to keep human subjects hyperhydrated for extended periods of time and thereby reduce the amount of fluid consumption necessary just prior to or during bouts of negative fluid balance situations.

Administration, Oral↗

PubMedDate not supplied

Effects of pyridinium chlorochromate adulterant (urine luck) on testing for drugs of abuse and a method for quantitative detection of chromium (VI) in urine.

Pyridinium chlorochromate (PCC) as an adulterant is popular for concealing drug-positive results. When 11-nor-delta9-THC-9-carboxylic acid (THC-acid) in urine was treated with 2 mmol/L of PCC (Cr6+ 104 microg/mL), 58-100% of the THC-acid was lost. The loss increased with decreasing pH and increasing reaction time (0-3 days). Free codeine and free morphine remained unaffected by PCC at pH within the physiological range of the urine (pH 5-7). At lower pH, the loss of free morphine varied from 0 to 100%. Amphetamine, methamphetamine, benzoylecgonine, and PCP remained unaffected by PCC when exposed to the oxidant for three days in urine pH of 3-7. Chromium (VI) from PCC in a urine solution was detected by a color reaction with 1,5-diphenylcarbazide (DPC). When the reagent was added to the urine, an immediate red-violet color appeared. The chromium-DPC complex showed a characteristic absorption peak at wavelength 544 nm with a shoulder at wavelength 575 nm. The ratio of absorption was used to identify the chromium compound. The concentration of chromium (VI) was determined by measuring absorption at wavelength 544 nm and was linear over 0.5-20 microg/mL. The limit of detection of the procedure was 0.37 microg/mL.

Anti-Infective Agents↗

PubMedDate not supplied

Correlation of expression of NCAM and GD3 ganglioside to motile behaviour in neoplastic glia.

Studies of developing mammalian tissues have established that certain neural cell adhesion molecules (NCAMs) may be down-regulated during the migratory phase concurrent with an increase in levels of matrix metalloproteinases. In addition, there is evidence that simple gangliosides such as GD3 are transiently present on the surface of such migratory cells. Since migration, or motility, is a prerequisite for diffuse local invasion of brain by neoplastic cells, the expression of NCAM and GD3 on brain tumour cells was studied in order to establish their possible role in the invasive process. An astrocytoma parent cell line (IPSB-18) and two morphologically distinct, cloned cell lines (clone 1 and 12) derived from it, were used in in vitro motility assays using 8 microns porosity polycarbonate filters in "Transwell" modified Boyden chambers. Immunocytochemical staining with anti-NCAM monoclonal antibodies (UJ13A and ERIC-1) and with the anti-ganglioside monoclonal antibodies LB1 (which recognises GD3) and A2B5 (which recognises a range of simple gangliosides) showed that some cells in culture from the parent line were positive for either NCAM or GD3; clone 1 was NCAM positive but GD3 negative, while clone 12 was NCAM negative but ganglioside positive. Motility assays showed that although clone 12 migrated more efficiently than either clone 1 or the parent line, this was not statistically significant. Moreover, similar assays were conducted on two further sub populations of cells which were evolved from the immunomagnetic separation of the parent cell line, IPSB-18, according to NCAM expression (i.e. NCAM positive and NCAM negative). The results indicated that the NCAM negative cells migrated more efficiently than the NCAM positive cells, in a time-dependent manner, when incubated for 4, 12 and 18 hours in Boyden chambers. These findings suggest that during the migratory phase of brain tumour invasion, NCAM expression is down-regulated whereas ganglioside expression is up-regulated.

Antibodies, Monoclonal↗

PubMedDate not supplied

Nm23: an invasion suppressor gene in CNS tumours?

The nm23 gene family is widely documented as a suppressor of the metastatic phenotype in many human cancers. However, its role with respect to the invasive behavior of primary central nervous system tumours has scarcely been addressed. This review describes the members of this family identified to date and outlines the in vitro and in vivo data gathered from nearly ten years of nm23 research within the context of malignant progression in peripheral tumours. It is clear that this is an area which can no longer be ignored by the brain tumor community. Human nm23 bears strong sequence homology to the awd gene in Drosophila, mutations in which cause abnormal morphology of larval neural tissue. The functions and possible mechanisms underlying the ability of nm23 to suppress metastatic behavior are discussed.

Animals↗