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Biomedical subjects

J M Potter

Publications and source records attributed to J M Potter.

At least 37 records · Page 2Linked to original sources
PubMed1996

The use of the lidocaine-monoethylglycinexylidide test in the liver transplant recipient.

The lidocaine-monoethylglycinexylidide (MEGX) test is used to monitor liver function in liver transplant recipients. Serial studies have been undertaken after 155 allografts. The initial MEGX concentration is significantly correlated with the donor MEGX concentration. It is also influenced by the recipient's pretransplant bilirubin concentration, being lowest among patients with very high bilirubin levels. Use of segmental grafts is also accompanied by low MEGX concentrations. The flow-dependent clearance of lidocaine makes it a sensitive indicator of disturbed liver blood flow, with decreased MEGX concentrations occurring in hepatic artery thrombosis and rejection and as a result of cardiac failure and pulmonary effusions. Significant hepatic ischemia resulting in delayed initial function or cholestasis also is associated with low MEGX concentrations. The initial median MEGX concentrations were lowest among patients who required retransplantation or who died within 2 months of allografting.

Adolescent↗
PubMed1995

Gait speed and activities of daily living function in geriatric patients.

OBJECTIVE: To establish the relationship between gait speed (GS) and functional independence in elderly people. DESIGN: GS is suggested as being a criterion standard in rehabilitation reflecting muscle strength. This study assessed the relationship between gait speed and functional independence in Activities of Daily Living (ADL). GS was measured by portable accelerometer over 2 meters. The mean of 3 attempts was taken. ADL function was measured by an occupational therapist using the modified Barthel ADL Index. The relationship between these measures was assessed by a statistician. SETTING: A geriatric unit in a hospital in Scotland. PATIENTS: One hundred sixty-one inpatients and outpatients were selected at random from the patients of a geriatric unit over a 3-month period. Patients were eligible if they were mobile with or without a walking aid. INTERVENTIONS: GS was measured by portable ultrasonic accelerometer. Patients were reviewed by an occupational therapist, blinded to their GS, who recorded functional capacity. Case sheet review provided diagnostic details and cognitive function. The type of floor surface was recorded. MAIN OUTCOME MEASURES: GS (m/sec), and Barthel score. RESULTS: Patients with GS of < .25m/sec were more likely to be dependent in one or more ADL function, p < .01. Those with a GS between .35 and .55m/sec were more likely to be independent in all ADL functions, p < .001. Patients whose GS was > .55m/sec did not maintain this independence. There was no relationship between GS and floor surface or cognitive function. CONCLUSIONS: GS is a useful indicator of ADL function in geriatric patients.

Activities of Daily Living↗
PubMed1994

Living wills: would sick people change their minds?

Patients admitted acutely to a geriatric medical unit were interviewed on admission about their opinions on cardiopulmonary resuscitation (CPR). They underwent a general examination and their mental health was documented by completing the geriatric depression scale. Those who did not wish CPR in the event of a cardiac arrest were questioned again on recovery. Of 216 patients admitted, only three objected to answering the questions and after the other exclusion criteria were applied, 100 patients were included in the study. A total of 92% of patients wished CPR in the event of a cardiac arrest. The 8% who did not wish CPR contained more people scoring high on the geriatric depression scale. After recovery, three of that eight had changed their minds and wished CPR if required. Patients who are acutely unwell may make decisions that are influenced by their condition at this point in time and it is important to recognize that these decisions may not be maintained. In this study, consultant geriatricians did not reflect their patients' desires in making decisions about who should receive CPR if required.

Acute Disease↗
PubMed1993

Basic pharmacology.

Explore the source record for details and available documents.

Pharmaceutical Preparations↗
PubMed1993

Lignocaine metabolism and liver function testing in primary graft failure following orthotopic liver transplantation.

OBJECTIVE: To report the use of lignocaine and the measurement of its metabolite, monoethylglycinexylidide (MEGX), as a dynamic test of liver function. CLINICAL FEATURES: The conversion of lignocaine to MEGX has been used serially as a test of liver function in a liver transplant recipient for whom retransplantation was necessary because of primary non-function (PNF) of the initial graft. MEGX concentrations were markedly depressed with individual episodes of PNF, cardiac failure and rejection in this patient. CONCLUSION: The test provided useful additional supportive information in assessment of the patient and management of intercurrent problems following liver transplantation.

Female↗
PubMed1993

Use of monoethylglycinexylidide as a liver function test in the liver transplant recipient.

The hepatic conversion of lignocaine to monoethylglycinexylidide (MEGX) has been used as a real time monitor of liver function in liver transplant recipients. Data are reported for the first 4 weeks after transplant in 50 consecutive orthotopic liver grafts in 47 adults. The MEGX concentration was significantly depressed by approximately 50% in those patients in whom there was a complicated clinical course (excluding steroid-sensitive rejection) after transplantation, compared with patients in whom major complications did not occur. The MEGX concentration in the recipients after transplant was independent of the donor MEGX concentration, but, in addition to the patient's clinical status, was strongly influenced by the recipients pretransplant biochemical profile, being inversely related to the pretransplant bilirubin concentration. MEGX concentrations < 25 micrograms/L in the first 36 hr after revascularization were predictive of greater morbidity and mortality.

Adolescent↗
PubMed1992

High-performance liquid chromatographic method for the simultaneous determination of monoethylglycinexylidide and lignocaine.

An accurate and sensitive high-performance liquid chromatographic method with UV detection was developed for the simultaneous measurement of monoethylglycinexylidide (MEGX) and lignocaine in human plasma and serum, using organic solvent extraction and trimethoprim (TMP) as an internal standard. The mean recoveries for MEGX, TMP and lignocaine were 86.1 +/- 3.7, 98.3 +/- 1.8 and 77.0 +/- 4.7%, respectively (n = 6). The relative standard deviations for MEGX concentrations of 10 and 200 ng/ml were less than 4% and for lignocaine concentrations of 200 and 1200 ng/ml they were less than 8%.

Chromatography, High Pressure Liquid↗
PubMed1992

Altered in vitro lymphocyte response in childhood nephrotic syndrome.

The immune system, and disturbed T lymphocyte function in particular, has previously been implicated in the pathogenesis of childhood idiopathic nephrotic syndrome. As this disorder is commonly responsive to steroid therapy, we set out to determine whether in vitro suppression of lymphocyte blastogenic response to the mitogen phytohaemagglutinin (PHA) could predict the clinical situation. Comparing nine nephrotic children with nine healthy controls we were able to show the inhibitory prednisolone dose that suppressed lymphocyte blastogenesis by 50% (ID50) at a known concentration of PHA was significantly greater (P < 0.005) for nephrotic individuals. However, the in vitro assay did not reliably predict the clinical response to prednisolone. This study further implicates altered lymphocyte function in the mechanisms underlying idiopathic nephrotic syndrome.

Adolescent↗
PubMed1992

Cardiodepressant drugs and the high mortality rate associated with ischemic hepatitis.

OBJECTIVE: To show that patients are more likely to die in the event of ischemic hepatitis if they take drugs where clearance is dependent on liver blood flow and where a high dose produces myocardial depression. DESIGN: The drug management was studied in a case series of 28 patients in whom ischemic hepatitis was diagnosed. SETTING: Inpatients in a major teaching hospital. PATIENTS: Patients were identified by an increase in circulating aspartate aminotransferase activity to greater than 1000 U/L and a clinical history of a hypotensive episode or cardiac failure. MAIN OUTCOME MEASURE: All drug use from 12 hrs before the hypotension or onset of cardiac failure was recorded. The clinical outcome was categorized as death during the acute event (ischemic hepatitis) or recovery. RESULTS: Acute mortality rate was 60.7%. Among nonsurvivors, calcium-channel antagonists and antiarrhythmic drugs were used in ten (58.8%) of 17 patients, compared with two (18.2%) of 11 survivors (chi 2 = 4.504, p less than .05). CONCLUSIONS: The patient who is or has been recently receiving calcium-channel blockers and/or antiarrhythmic drugs has a poor prognosis in the event of ischemic hepatitis, with a mortality rate of 83%. Further study may show whether this mortality rate reflects the severity of the premorbid cardiovascular disease in these patients or whether the presence of these drugs renders the patients more resistant to inotropic support.

Adolescent↗
PubMed1992

A quick, sensitive high-performance liquid chromatography assay for monoethylglycinexylidide and lignocaine in serum/plasma using solid-phase extraction.

Recent advances in the investigation of liver disease and transplantation have seen the introduction of lignocaine as a probe of liver function. For this purpose, an assay that is sensitive and rapid is required for the major metabolite of lignocaine, monoethylglycinexylidide (MEGX). We have developed an accurate, low-cost high-performance liquid chromatography (HPLC) method using Bond-Elut phenyl (1 cc) cartridges for sample preparation. The total preparation time for five samples is less than 10 min and the run time is approximately 10 min/sample. Each cartridge can be used at least four times. Simultaneous measurement of another metabolite of lignocaine, glycinexylidide (GX), can be achieved by adjustment of the mobile phase and flow rate. The chromatogram is monitored with an UV detector at 210 nm. The inter- and intra-assay coefficients of variation for MEGX (10-250 micrograms/L) and lignocaine (100-2,000 micrograms/L) are less than 9.5 and less than 2%, respectively, with recoveries for MEGX, trimethoprim (internal standard), and lignocaine all greater than 85%. This method offers a rapid, sensitive assay that is clinically useful in the new role for lignocaine/MEGX in dynamic liver function testing.

Chemistry Techniques, Analytical↗
PubMed1992

Fluorescence polarization immunoassay and HPLC assays compared for measuring monoethylglycinexylidide in liver-transplant patients.

We compared fluorescence polarization immunoassay (FPIA, x) and HPLC (y) for measuring monoethylglycinexylidide (MEGX) concentrations in 119 serum samples from 61 liver-transplant donors and recipients. The correlation between the two methods was y = 1.48 micrograms/L + 0.8x (r = 0.89). The bias (mean difference) was 12 micrograms/L (0.055 mumol/L) through the MEGX concentration range measured (0-250 micrograms/L, 0-1.136 mumol/L). We observed a major difference between the two methods in samples from four recipients and one donor. Cross-reactivity in FPIA with lignocaine and two of its metabolites (glycinexylidide and 2,6-xylidine) was < 3%. Samples with high bilirubin concentrations (> 200 mumol/L) required dilution before assay of MEGX by FPIA. Although there was an increase in apparent MEGX concentrations in some samples with increased bilirubin concentrations, the relationship was not constant. Increased plasma concentrations of cholesterol and triglyceride resulted in relatively small increases in apparent MEGX concentrations.

Bilirubin↗
PubMed1992

The decline in geriatric long stay beds: who remains?

A day census of all long-term hospital patients in the Canterbury geriatric service area was carried out in 1984 (when there were 127 beds) and repeated in 1989 (when there were 66 beds). The patients in the 1989 census were more confused and physically more dependent than those in 1984. Comparison with residents in local residential and nursing homes in 1987 shows that a higher proportion of long-term hospital patients had severe mental and physical disability. There is a hard core of patients who are difficult to place outside hospital. This has predictable resource implications and in Canterbury such patients will continue to occupy National Health Service beds as there are no practicable alternatives.

Activities of Daily Living↗