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Biomedical subjects

D Lucas

Publications and source records attributed to D Lucas.

At least 91 records · Page 5Linked to original sources
PubMed1988

Acetaldehyde adducts with haemoglobin: determination of acetaldehyde released from haemoglobin by acid hydrolysis.

Acetaldehyde, the first metabolite of ethanol, reacts with haemoglobin in vitro to produce acetaldehyde-haemoglobin adducts. Some clinical studies on the minor haemoglobins have suggested that these adducts may be formed in people abusing alcohol. Under hydrolysis of haemoglobin, with oxalic acid at 100 degrees C in sealed vials, some acetaldehyde was released and then specifically determined by HPLC. The kinetics of hydrolysis were studied using haemoglobin previously labelled with 14[C] acetaldehyde. The maximum liberation of 14 [C] acetaldehyde was obtained after 3 hr 30 min hydrolysis and this time factor was then utilized in the analysis of alcoholic and control haemoglobin. Thus, we have confirmed the formation of acetaldehyde haemoglobin adducts in vivo. It must be noted that the released acetaldehyde corresponds only to an index of the stable adducts. The levels were higher in alcoholics than in controls (1.417 +/- 0.171 and 1.295 +/- 0.139 nmol/mg Hb, respectively, P less than 0.001). In conclusion, this marker is not a convenient tool for the monitoring of alcohol exposure levels because of the low differences between alcoholic and control haemoglobins.

Acetaldehyde↗
PubMed1987

Health status of Ethiopian refugees in the United States.

The health status of 239 Ethiopian refugees in the United States was evaluated. Over 70 per cent were males 15-30 years old. Positive PPDs (purified protein derivative of tuberculin) were observed in 72 per cent and 3.4 per cent had abnormal chest x-rays. One patient had active tuberculosis. Other laboratory abnormalities included: intestinal parasites (36.7 per cent), anemia (14.9 per cent), eosinophilia (14 per cent), positive syphilis serology (7.5 per cent), and hepatitis B surface antigenemia (9.4 per cent). The most prevalent intestinal parasites were Giardia lamblia, Trichuris trichiura, and Schistosoma mansoni.

Adolescent↗
PubMed1987

[Clinico-anatomic studies of the carpal tunnel of the human hand].

Numerous investigations of the carpal tunnel were performed in 60 human hands of adults. In detail we determined the length, width, and thickness of the flexor retinaculum. Furthermore the dimensions of the carpal tunnel and the proximal, middle and distal cross-section areas were calculated. We found that the middle region is the narrowest portion of the carpal tunnel. The median nerve increases constantly in width from proximal to distal in the carpal tunnel whereas its thickness decreases. In 43.3% the nerve passes radially from the middle of the tunnel to the palm. In 21.7% the median nerve is located exactly under the middle of the flexor retinaculum and only in 1.7% is it shifted to the more ulnar side. The median nerve shows a winding course in the remaining cases.

Adult↗
PubMed1986

Determination of free acetaldehyde in blood as the dinitrophenylhydrazone derivative by high-performance liquid chromatography.

A simple and sensitive method is proposed for the measurement of acetaldehyde in human blood. Venous blood samples were collected in EDTA Vacutainer tubes, and treated immediately with 0.6 M ice-cold perchloric acid in saline. After centrifugation at 4 degrees C, the supernatants were treated with dinitrophenylhydrazine reagent. After addition of the internal standard (crotonaldehyde dinitrophenylhydrazone) and 3 M sodium acetate, the derivatives were extracted and analysed by high-performance liquid chromatography (HPLC) using an Ultrasphere ODS column. The compounds were separated using acetonitrile--water as the mobile phase and detected at 356 nm. A blank determination was carried out for each analysis and subtracted from the results. The specificity of the method was tested by UV and mass spectrometry and the purity of the derivatives by capillary gas chromatography. The recovery of blood acetaldehyde was 98%. Interference from ethanol was minimized by using the tripotassium salt of EDTA as an anticoagulant. The sensitivity of the method can be increased dramatically using microbore HPLC. The level of acetaldehyde was found to be 0.41 +/- 0.13 microM (mean +/- S.D.) for eight fasting controls and 0.91 +/- 0.73 microM for fourteen alcoholics (p less than 0.05). At 30 min after oral administration of ethanol (0.8 g/kg), the ethanol levels were 16.3 +/- 2.8 and 17.7 +/- 2.5 mM and the acetaldehyde levels were 1.67 +/- 0.35 and 3.13 +/- 2.43 microM (p less than 0.05) for the controls and alcoholics, respectively.

Acetaldehyde↗
PubMed1986

Effects of selenium in vitro on human T-lymphocyte functions and K-562 tumor cell growth.

In vitro E-rosette formation, lymphocyte mitogenesis, and natural killer (NK) cell activity of human blood lymphocytes were strongly inhibited by high concentrations (10(-4) M) of sodium selenite, sodium selenate, and selenium dioxide. Lower concentrations (10(-5) or 10(-7) M) also inhibited E-rosette formation and natural killer cell activity against K-562 tumor cells. Lymphocyte transformation induced by concanavalin A (con A) or pokeweed mitogen (PWM) was also inhibited by all selenium compounds tested, but only at the highest concentrations (10(-5) and 10(-4) M). There was depression of the total number of viable lymphocytes following incubation with selenium dioxide only at a high concentration (10(-4) M). Interferon production was enhanced at lower levels (10(-9) to 10(-6)M) of selenium dioxide while a higher concentration (10(-5) and 10(-4)M) appeared to inhibit its production. The mechanism of inhibition by selenium compounds (10(-4) M) is due, in part, to the decrease of viable lymphocytes. It is unclear how other and lower concentrations (10(-7) or 10(-9) M) of selenium compounds inhibit E-rosette formation, NK activity, or K-562 tumor cell growth.

Adult↗
PubMed1986

Acetaldehyde adducts with serum proteins are not responsible for decreased drug binding in alcoholic patients.

Decreased plasma binding of phenytoin and diazepam has previously been described in patients with alcoholic liver diseases. It has been attributed to hypoalbuminemia, endogenous displacers and/or qualitative changes in albumin such as formation of adducts with acetaldehyde, a highly reactive metabolite of ethanol. In the present report this hypothesis was tested. After treating the sera with activated charcoal to remove the endogenous displacers and adjusting albumin concentration to a constant level, the binding parameters of both drugs, phenytoin and diazepam, were determined in 14 healthy men and 16 alcoholic patients by equilibrium dialysis. In these conditions, no significant difference in the number of binding sites nor in the affinity constant was observed, which suggests that acetaldehyde adducts with proteins do not contribute, to a major extent, to the defect of drug binding observed in alcoholic patients.

Acetaldehyde↗
PubMed1986

[High-resolution nuclear spin tomography of the hip joint using a Helmholtz surface coil].

A specially constructed Helmholtz surface coil enables one to obtain high resolution nuclear tomograms of the hip. Anatomical structures which are clinically important and which can regularly be shown are described. A pilot study has been carried out on 16 patients and typical findings are described in necrosis of the femoral head, osteoarthritis and changes resulting from tumours in the region. Possible further applications are discussed.

Adult↗
PubMed1986

The wrist: a preliminary report on high-resolution MR imaging.

Excellent spatial resolution is required to demonstrate the complex region of the wrist, with its diverse structures comprising bone, cartilage, and ligaments. Magnetic resonance (MR) imaging was done with a Magnetom imaging system operating at 1.0 T. Use of a flat surface coil enabled excellent spatial resolution and a section thickness of 4 mm. Twenty-nine patients with navicular nonunion or pseudarthrosis, rheumatoid arthritis, recent fractures, soft-tissue alterations, and bone tumors were examined. All patients had undergone radiography and bone scintigraphy. In this limited sampling, MR was found to detect and characterize marrow and articular alterations more accurately, and earlier, than either of those modalities.

Bone Diseases↗
PubMed1986

Acetaldehyde adducts with serum proteins: effect on diazepam and phenytoin binding.

The in vitro effects of acetaldehyde treatment on the binding of phenytoin and diazepam to human serum albumin (HSA) and human serum proteins (HSP) have been investigated. The incorporation of acetaldehyde into proteins following incubation with different concentrations of [1,2-14 C]-acetaldehyde (0.5, 25, 100 mmol/l) was carried out. The proteins were then dialyzed so that only the stable adduct was retained. Binding of phenytoin and diazepam was then studied. Scatchard plot analysis showed a slight decrease (p less than 0.01 for HSP and 25 mmol/l acetaldehyde) in the number of binding sites for phenytoin when the acetaldehyde/protein ratio was increased. The affinity constant was also increased (p less than 0.01) with 100 mmol/l acetaldehyde. No change could be demonstrated in the number of diazepam binding sites on HSA; an increase in the binding capacity of HSP was shown following incubation with 25 mmol/l acetaldehyde. The fraction of drug bound at therapeutic levels has been also calculated for both drugs. An increase for diazepam but no change for phenytoin can be observed before or after treatment of proteins with acetaldehyde.

Acetaldehyde↗
PubMed1985

Retinoic acid-induced expression of tissue transglutaminase in human promyelocytic leukemia (HL-60) cells.

Addition of retinoic acid to human promyelocytic leukemia cells results in a dramatic increase in cellular transglutaminase activity. This increase is due to the induction of a specific intracellular transglutaminase, tissue transglutaminase. Retinoic acid-induced expression of tissue transglutaminase is potentiated by analogues of cyclic AMP. The induction of the enzyme can be detected within 6 h of the addition of the retinoid to the cell and results in increases of the enzyme of at least 50-fold. The induction of HL-60 transglutaminase is a specific response of the cells to retinoic acid and is not seen with other agents that induce HL-60 differentiation. We believe that the induction of tissue transglutaminase is a useful index of the early events in retinoid-regulated gene expression in both normal and transformed cells.

Acyltransferases↗
PubMed1985

[Nonocclusive ischemic enteropathy--a rare cause of ileus].

The cause for a nonocclusive ischemic enteropathy seems to be a low cardiac output syndrome. There are often signs of a paralytic intestinal obstruction. Parameters of the blood chemistry offer no conclusive data. The angiogram of the mesenteric vessels demonstrates extensive arterial vasoconstriction as well as an obstructed venous outflow. Experimental findings disclose that this venous obstruction may be a result of an ischemic contracture in the course of a low flow state. This rigor initiates finally a thrombosis of the venoles. The rigor can be effectually mastered by energy-rich compounds.

Calcium↗
PubMed1985

Population problems in the South Pacific islands: an overview.

"This paper attempts to pull together a broad review of what is known about--or, in many cases, presumed to be--the current demographic situation in the islands of the Pacific, and point out some economic and social consequences of those demographic trends." Data are included on births, deaths, natural increase, migration, education, health services, remittances, the dependent population, employment, and food supply.

Conservation of Natural Resources↗
PubMed1984

Perinatal assessment of glycaemic control in newborn infants of diabetic mothers.

The glycaemic control of infants and of their mothers was studied at delivery and on day 7 after birth in 11 control and 20 insulin-dependent diabetic women. At delivery, venous blood glucose was lower in infants of diabetic mothers compared with control infants (p less than 0.02). Seven days after birth, no significant difference in blood glucose could be found between control and infants of diabetic mothers. C-peptide levels were higher in infants of diabetic mothers compared with control infants (p less than 0.01). On day 7 after birth, the C-peptide levels remained higher only in infants of Class B, C, D diabetic mothers. Glycosylated haemoglobin was lower in the venous blood of infants than of their mothers (p less than 0.001). Glycosylated haemoglobin was lower in control mothers than in diabetic mothers (p less than 0.05), but it was higher in the venous blood samples from control infants compared with infants of diabetic mothers at delivery (p less than 0.05) and 7 days after (p less than 0.01). At delivery infants' glycaemia and infants' glycosylated haemoglobin correlated (r = 0.44, p less than 0.02). C-Peptide and glycosylated haemoglobin levels in infants at delivery also correlated (r = -0.42, p less than 0.05).

Blood Glucose↗