Search PubMed⌕ Search

Biomedical subjects

F M Ali

Publications and source records attributed to F M Ali.

32 records · Page 2Linked to original sources
PubMed1981

Melanoma detection by enzyme-radioimmunoassay of L-dopa, dopamine, and 3-O-methyldopamine in urine.

This enzyme-radioimmunoassay for the measurement of L-dopa, dopamine, and 3-O-methyldopamine is based on the incubation of urine in the presence of catechol-O-methyltransferase, aromatic-L-amino-acid decarboxylase, and S-adenosylmethionine. The O-methylated dopamine metabolite formed, 3-O-methyldopamine, was characterized by radioimmunoassay. To evaluate the role of L-dopa metabolism in melanoma, we used the enzyme-radioimmunoassay to assess concentrations of L-dopa, dopamine, and 3-O-methyldopamine in urine from 10 healthy subjects, 10 hospitalized patients without melanoma and 28 patients with different degrees of melanoma. The effect of surgery for melanoma on urinary output of these catechols of melanoma patients was also evaluated. No significant difference in urinary L-dopa, dopamine, and 3-O-methyldopamine excretion rates was seen between normal subjects (L-dopa 1.3 +/- 0.3, dopamine 147 +/- 38, and 3-O-methyldopamine 31.4 +/- 13.6 microgram/24 h), hospitalized patients without melanoma, and amelanotic melanoma patients. However, the excretion rates for these metabolites in melanotic melanoma (L-dopa 5.6 +/- 1.2, dopamine 555 +/- 121, and 3-O-methyldopamine 178 +/- 40.3 microgram/24 h) were significantly (p < 0.005) higher than in control or amelanotic melanoma subjects. After surgery, there was a substantial decrease in urinary output of L-dopa and its metabolites by these patients.

Adolescent↗
PubMed1981

Development and application of a radioimmunoassay for tetracycline.

Antiserum against tetracycline was produced in rabbits immunized with a tetracycline hapten conjugated to bovine serum albumin. The antiserum was used to develop a radioimmunoassay for tetracycline. As little was 1 ng of tetracycline can be detected in one sample. The antitetracycline antiserum showed a considerable degree of specificity since it cross-reacted only with chlortetracycline (70%). However, its cross-reactivity with oxytetracycline, doxycycline, demeclocycline, methacycline and rolitetracycline was only negligible. The radioimmunoassay of tetracycline was used to measure the systemic bioavailability of orally administered tetracycline (25 mg/kg) to a group of mongrel dogs. Detectable levels of tetracycline were exhibited within 30 min and maximum plasma concentrations of the drug occurred within 3 to 4 hr after dose administration.

Animals↗
PubMed1980

Immune deficiency in Hodgkin and non-Hodgkin lymphoma.

Forty-three previously untreated Egyptian patients with Hodgkin's disease and thirty-five patients with non-Hodgkin lymphoma were studied with several readily available tests of immune function, number of peripheral blood lymphocytes, delayed hypersensitivity to two recall antigens, in vitro blastoid transformation by PHA, the capacity of E-rosette formation and surface marker criteria. The results were correlated to the histology, stage of disease and to the presence of general symptoms and signs.

Granulocytes↗
PubMed1979

Tyramine kinetics and metabolism in cirrhosis.

Hypertyraminemia is common in hepatic cirrhosis and correlates in severity with encephalopathy. The mechanism of cirrhotic hypertyraminemia has not been established. The alternative possibilities are increased production from tyrosine and impaired degradation by monoamine oxidase. This investigation determined the pharmacokinetics of tyramine after an intravenous bolus injections of [3H]-tyramine (180--200 muCi 12 Ci/mmol sp act) in 13 cirrhotics and 9 controls. In normals, [3H]tyramine levels initially declined rapidly (alpha-phase) followed by a slower decline (beta-phase) with an average t 1/2 of 20.8 min. Average normal metabolic clearance rate and production rate were 13.2 liters/min and 15.4 microgram/min, respectively. In cirrhotic patients, the plasma disappearance curve for [3H]tyramine was qualitatively similar to that of the control subjects with no apparent different in beta-t 1/2 (17.2 min). The hypertyraminemia of cirrhosis resulted primarily from overproduction of tyramine, as the production rate (32.0 microgram/min) in these patients was significantly greater (P less than 0.05) than in controls, whereas the metabolic clearance rate remained normal (average 12.2 liters/min). A difference in ratio of tyramine metabolic products was noted as well. Cirrhotics had a high ratio of plasma 4-hydroxyphenylethanol:4-hydroxyphenylacetic acid (60:40 vs. 30:70) as compared with normals. Although the tyramine clearance rates are similar in normals and cirrhotics, different mechanisms may be responsible for catabolism.

Adult↗
PubMed1979

Evidence for hypertyraminemia in Reye's syndrome.

Utilizing a specific and sensitive radioimmunoassay, palsma and urine tyramine were measured in 14 consecutive patients with liver biopsy-proven Reye's syndrome. Plasma tyrosine was measured in 11 of these patients. The results revealed significant (P less than .003) elevation in plasma (3.4 +/- .52 ng/ml) (mean +/- SEM) and urine (1.00 +/- .26 mg/24 hr) tyramine as well as plasma tyrosine (204 +/- 52.5 mumole/liter) at the onset of the disease when compared to the levels of tyramine and tyrosine in a group of hospitalized patients without hepatic disorders. Furthermore, there was a positive correlation between plasma tyramine and days in coma (r = .86; P less than .001), and between plasma tyramine and tyrosine (r = 0.80; P less than .001). These data suggest that there is s substantial disturbance of tyrosine metabolism in Reye's syndrome and that the accumulation of this amino acid and its metabolite, tyramine, may contribute to the encephalopathy of this disease.

Adolescent↗
PubMed1979

Tyrosine metabolism in cirrhosis.

The aim of this study was to define the enzyme defect responsible for tyrosinemia in cirrhotic patients. The principal hepatic degradation pathway for tyrosine, tyrosine leads to p-hydroxyphenylpyruvic acid equilibrium homogentisic acid leads to CO2 was studied in 18 cirrhotic patients and eight controls. The classic method employed in elucidation of hereditary tyrosinosis was sued. Metabolic intermediates on the pathway were measured in the basal state, and following oral loading doses (50 mg/kg BW) of tyrosine, PHPA, and homogentisic acid. Cirrhotic patients showed a significant increase (p = 0.005) in fasting plasma tyrosine and in basal PHPA excretion and impaired tolerance to all three metabolites when compared to normals. Fifteen of the 18 cirrhotic patients showed tyrosine intolerance which was not accompanied by change in distal metabolites compared to their basal levels. Nevertheless 13 of the 18 did exhibit intolerance of either PHPA or homogentisic acid. We conclude that in contrast to the single complete defect in hereditary disorders of tyrosine metabolism, cirrhotic patients have partial defects at tyrosine transaminase, PHPA oxidase, and homogentisic acid oxidase, the initial step being rate-limiting.

Adult↗
PubMed1978

Decarboxylation to tyramine: an important route of tyrosine metabolism in dogs with experimental hepatic encephalopathy.

Tyrosine metabolism via decarboxylation to tyramine was evaluated in dogs with functional end-to-side portacaval shunt. It was found that the endogenous plasma levels of both tyrosine and tyramine increased steadily after the construction of the shunt. These elevations became more pronounced when the dogs manifested symptoms of hepatic encephalopathy. In encephalopathic dogs, average endogenous plasma tyrosine and tyramine concentrations were 110.1 mumoles per liter and 7.6 ng per ml as compared to 55.4 and 1.2 in control dogs, respectively. The pattern of plasma concentrations of tyrosine and tyramine after an oral dose of L-tyrosine (50 mg per kg) was also investigated in control and shunted dogs. There was a progressive rise in peak levels of tyramine (to about 50-fold increase, at 6 weeks) after the construction of the shunt, as compared to levels obtained in pre- and at 1 and 4 weeks postoperatively (70.6 versus 1.20, 3.9, and 8.11 ng per ml). Similar observations were made with levels of plasma tyrosine. Six weeks after portacaval shunt, mean peak levels of plasma tyrosine, achieved at 5 hr after dose administration, were 450 as compared to 85 mumoles per liter obtained in preshunted dogs. These studies demonstrated a correlation between abnormalities in tyrosine metabolism and postshunt hepatic encephalopathy.

Amino Acids↗
PubMed1977

The measurement of 3-o-methyldopamine in urine and plasma by a rapid and specific radioimmunoassay.

Antiserum against 3-O-methyldopamine (MD) was produced in rabbits immunized with MD hapten conjugated to hemocyanin. The antiserum was used to develop a radioimmunoassay (RIA) for MD. As little as 0.5 ng of MD in 0.1 ml can be detected. The major catecholamines and the phenolic aromatic amines (dopamine, norepinephrine, epinephrine, octopamine, and tyramine) and their metabolites (normetanephrine, metanephrine, homovanillic acid and 4-hydroxy-3-methxymandelic acid) did not bind significantly to the antibody. The RIA of MD was used to assay the endogenous level of MD in urine and plasma of hospitalized children. In children (7 mo to 13 yr), average concentration of MD in plasma was found to be 0.47 +/- 0.11 ng/ml, and in urine 0.15 +/- 0.05 microgram/mg of creatinine (45.0 +/- 16.3 microgram/24 hr). In children with neuroblastoma, there was a 3- to 10-fold increase in urinary excretion and plasma level of 3-O-methyldopamine. In adults, the average urine and plasma levels were found to be 87.4 +/- 3.4 microgram/24 hr and 0.6 +/- 0.2 ng/ml. The diagnostic applicability of the RIA of MD is discussed.

Adolescent↗
PubMedDate not supplied

Sex hormone status in male rats after exposure to 50 Hz, 5 mTesla magnetic field.

The question of whether extremely low frequency magnetic fields can affect biological system has attracted attention. The theoretical possibility of such an interaction is often questioned and the site of interaction is unknown. The influence of extremely low frequency magnetic field of 50 Hz, 5 mTesla on sex hormone status was studied. 60 male albino rats were divided into 6 groups and were continuously exposed to 50 Hz, 5 mTesla magnetic field generated by magnetic field chamber for periods of 1, 2 and 4 weeks. For each experimental point, sham treated group was used as a control. Assay of serum testosterone LH, FSH, and prolactin were performed. Serum testosterone showed no significant changes. FSH showed significant increase than sham exposed group after 1 week magnetic field exposure. LH showed significant increase than sham exposed group only after 4 weeks magnetic field exposure, while serum prolactin hormone level showed a significant increase in all magnetic field exposed groups than sham exposed animals. Exposure to 50 Hz, 5 mTesla magnetic field for periods of 1, 2 and 4 weeks has no effect on testosterone level, some changes on FSH and LH serum levels and increase in serum prolactin level.

Animals↗