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Biomedical subjects

N G Beratis

Publications and source records attributed to N G Beratis.

At least 19 recordsLinked to original sources

Cefuroxime axetil in the treatment of acute otitis media in children.

Cefuroxime axetil was evaluated for clinical efficacy and tolerance in the treatment of acute otitis media in children. Fifty-five children, 5.0 to 10.8 years, were randomly assigned to receive 250mg cefuroxime axetil every 12 hours or 50mg/kg/day amoxicillin in three divided doses. Both treatment schemes lasted for 10 days. Acute otitis media was diagnosed by the presence of erythema and/or opacity with bulging of the tympanic membrane. A tympanogram was obtained upon enrollment to the study, as well as within 2 days after completion of therapy. Fifty-one children completed the treatment protocol. The cure rate was 74.1% for cefuroxime axetil and 75.0% for amoxicillin. Clinical improvement was noted in 25.9% of children treated with cefuroxime axetil and in 25.0% of those treated with amoxicillin. There was no clinical failure in the two treatment groups. None of the children experienced relapse of acute otitis media during the month following completion of therapy. The findings indicate that cefuroxime axetil given twice daily has comparable efficacy to amoxicillin given three times daily in the treatment of children with acute otitis media.

Acute Disease

Peripheral neuropathy in patients with beta-thalassaemia.

As some patients with beta-thalassaemia manifested neurological signs, clinical and electrophysiological investigations were carried out on 53 thalassaemic patients and 29 healthy control subjects. Twenty per cent of the patients showed clinical and electrophysiological findings of a mild peripheral sensorimotor neuropathy, mainly of the lower limbs. The clinical symptoms were numbness, pins and needles sensations, muscular cramps, myalgia and muscle weakness. The electrophysiological abnormalities were manifested by decreased motor conduction velocity (MCV) and prolonged F-wave latencies of the tibial and the peroneal nerves. Borderline increase in the latencies of the sensory potentials of the median nerve was also observed. The electromyographic findings of the patients with diminished MCVs were compatible with a predominantly motor peripheral neuropathy. This neuropathy appears during the second and third decade of life.

Action Potentials

Ureaplasma urealyticum colonization of full term infants: perinatal acquisition and persistence during early infancy.

In a prospective study 225 (35%) of 640 pregnant women who delivered at term had vaginal colonization with Ureaplasma urealyticum at the time of delivery. One hundred ninety-three full term infants born to U. urealyticum-colonized mother were cultured from the throat, eyes and vagina within the first 3 days of life. One hundred seven infants (55%) had at least one culture site positive for U. urealyticum (throat 41%, eyes 20%, vagina 40%). Rupture of membranes for greater than or equal to 12 hours and the mode of delivery did not affect vertical transmission of U. urealyticum. We were able to follow 108 infants during the first 3 months of life. Sixty-eight, 33 and 37% of the infants who were initially colonized with U. urealyticum in the throat, eyes and vagina, respectively, were still colonized when the follow-up cultures were obtained 3 months later. Fourteen of the 108 infants whom we followed developed a lower respiratory tract illness. In the pharyngeally colonized infants there was no increased risk for lower respiratory tract illness during early infancy compared with the pharyngeally noncolonized infants.

Eye

Hepatitis B in household contacts of children with beta-thalassemia.

The hepatitis B virus (HBV) markers have been studied in 184 household contacts of 110 thalassemic patients and 184 normal individuals matched for age and socioeconomic status with the study subjects. The mean age (+/- SD) in both patients and control subjects was 31.1 +/- 13.5 years. HBV infection had occurred in 51.6% of the household contacts and in 32.1% of the control subjects. This difference is highly significant (p less than 0.001). The most frequent marker observed was the antihepatitis B core IgG followed by the antihepatitis B surface antibody. It is noteworthy that none of the thalassemic patients infected in the past was seropositive for the hepatitis B surface antigen at the time of the study, whereas its frequency in the general population was 8.1%. The findings indicate that the household contacts of thalassemic patients have a greater seroprevalence for hepatitis B infection. Furthermore, the household contacts of thalassemic patients are infected at a younger age than the control population. The high infection rate with HBV in all groups tested suggests that vaccination should be considered not only for the household contacts of thalassemic patients but possibly for the entire Greek population.

Adolescent

Ocular abnormalities in patients with beta thalassemia.

We examined 29 patients with homozygous beta thalassemia. The mean age of the patients was 15.6 +/- 8.9 years. Twelve patients (mean age, 02.0 +/- 10.4 years) had one or more ocular abnormalities. Five patients had degeneration of the retinal pigment epithelium, one had lens opacities, two had lens opacities and degeneration of the retinal pigment epithelium, one had vascular abnormalities and degeneration of the retinal pigment epithelium, one had angioid streaks, lens opacities, and degeneration of the retinal pigment epithelium, and two had angioid streaks and degeneration of the retinal pigment epithelium. These abnormalities were observed in patients with both forms of beta thalassemia, major and intermedia. The frequency of the ocular abnormalities increased with age. The youngest patient with an ocular abnormality was 6 1/2 years old. There was no correlation between the abnormalities observed and the serum ferritin level, the mean hematocrit value, and the dose of deferoxamine given to the patients.

Adolescent

Angiokeratoma corporis diffusum in GM1 gangliosidosis, type 1.

A patient with severe deficiency of beta-galactosidase, who developed skin lesions of angiokeratoma corporis diffusum between the 3rd and 10th month of life, is described. The activity of other lysosomal enzymes, including alpha-neuraminidase, was normal. The first signs of the disease were noticed during the first month of life. By 3 months coarseness of the face and psychomotor retardation were present. In addition to angiokeratoma, he had large mongolian spots and several scattered slate-blue spots of pigmentation over his body. With the exception of the skin lesions, the other clinical signs and the course of the psychomotor deterioration were within the clinical picture of GM1 gangliosidosis, Type 1. Angiokeratoma, a manifestation of several lysosomal disorders, may appear in GM1 gangliosidosis during the first year of life.

Fabry Disease

Cardiac involvement in postnatal rubella.

Two cases of rubella myocarditis are reported: a 6-year-old boy who developed a complete, distal to His, atrioventricular block, during the third day of illness; and a 12-year-old boy who developed myocarditis with congestive heart failure 20 days following rubella infection. Although permanent pacing was required in the first patient, six years later he showed a normal growth and maintained normal activity. The second patient has deteriorated markedly and 6 months after the initial illness he had severe heart failure. It should be noted that myocarditis with abnormalities of the conduction system or congestive heart failure may be a complication to postnatal rubella.

Child

Galactose metabolism in transferase-deficient galactosaemic and normal long-term lymphoid cell lines.

The activity (mean +/- SD) of galactose-1-phosphate uridyl transferase in two long-term lymphoid cell lines from Caucasian patients with transferase deficiency galactosaemia, a heterozygote, and eight normal subjects was 0, 78 and 168 +/- 55 nmol UDPG consumed (mg protein)-1h-1, respectively. Also, no activity was found in erythrocytes and cultured fibroblasts from the patients. A small number of cells of the galactosaemic lines cultured in medium, in which galactose was substituted for glucose, survived for 37 days. Normal and galactosaemic lines incubated with D-galactose-[1-14C] liberated 218.2 +/- 65.6 and 18.1 pmol 14CO2 (mg cellular protein)-1 (6h)-1, respectively. The evolution of 14CO2 from D-glucose-[1-14C] was similar in normal and galactosaemic lines. In the presence of [3H]galactose the radioactivity incorporated into TCA-precipitated material of the galactosaemic lines was 6.8% of the normal lines. Approximately 26% and 1.3% of the total radioactivity was incorporated into molecular species with a molecular weight greater than 400,000 daltons in normal and galactosaemic cells, respectively. Similar molecules were identified in the cell-free medium of both normal and deficient cells except for an 18,000 daltons molecule identified only in the medium of the normal cells. These findings indicate that a small amount of galactose is metabolized in galactosaemic lines with no transferase activity.

Carbon Dioxide

Sanfilippo disease in Greece.

In a series of cases collected in most parts of the world, Sanfilippo disease type A is more frequent than type B. Skin biopsies were obtained from Greek patients suspected for Sanfilippo disease and cultured fibroblasts were assayed for both N-acetyl-a-glucosaminidase and sulfamidase activity. Eleven patients with Sanfilippo disease were identified. Ten of them were type B and one type A. The 10 patients with type B came from East-Central Greece and the neighboring areas of Thessaly and Macedonia. Both parents of the type A patient were from the Greek ethnic community of Turkey. It remains unknown whether or not the higher frequency of type B than type A appears only in Greece or if it occurs in other Mediterranean countries as well.

Acetylglucosaminidase

Cystathionase deficiency: the effect of cofactor on the stability of normal and abnormal enzyme from lymphoid cell lines.

Heating at 70 degrees C with and without added pyridoxal phosphate (PLP) had strikingly different effects on cystathionase protein from normal long-term lymphoid cell lines and on the enzymes from cells derived from patients with vitamin-B6-responsive cystathioninuria. PLP added to extracts of normal cells afforded complete protection against heat inactivation, whereas inactivation of the cystathionase protein in extracts obtained from two cystathioninuric lines was greater in the presence of PLP than in its absence.

Cells, Cultured

Alpha-L-fucosidase in cultured bone marrow fibroblasts from fucosidosis patients.

Bone marrow fibroblasts were cultured from two patients with fucosidosis type 2, six control subjects, and three patients with other lysosomal disorders. Optimal conditions for measuring alpha-L-fucosidase activity in lysates of these cells with the fluorogenic substrate 4-methylumbelliferyl-alpha-L-fucoside were established. The pH profile of normal bone marrow fibroblasts showed three peaks and a shoulder of enzymatic activity, with maximum activity at pH 4.75. In cells derived from fucosidosis patients two peaks of apparent alpha-L-fucosidase activity were obtained; the pH optimum was 4.5. alpha-L-Fucosidase activity (mean +/- SD) in the fucosidosis and control bone marrow fibroblasts was 2.5 and 312.4 +/- 10.9 nmoles 4-methylumbelliferone per milligram protein per hour, respectively. A reduction in the apparent specific enzymatic activity in the fucosidosis cells was observed by using increasing concentrations of cellular protein in the assay system. Mixing experiments between normal and fucosidosis cells gave the expected activities. These findings indicate that cultured bone marrow fibroblasts can be used for the diagnosis and study of fucosidosis.

Bone Marrow

Characterization of the molecular defect in infantile and adult acid alpha-glucosidase deficiency fibroblasts.

Different clinical expressions of acid alpha-glucosidase deficiency have been described. The present study was undertaken to investigate the basic metabolic defect in the infantile and adult forms of the disease. Acid alpha-glucosidase (EC 3.2.1.20) was purified from normal and from adult acid alpha-glucosidase deficiency fibroblasts. The pH optimum; Michaelis constant; electrophoretic mobility in starch; thermal denaturation at pH 4.0 and 7.0; and inhibition by turanose, alpha-methylglucoside and trehalose were the same in purified enzyme from normal and mutant cells. Placental acid alpha-glucosidase was purified to, or near, homogeneity. Monospecific antibodies raised against the enzyme in each of three enzyme peaks obtained from the last purification step were found to cross-react with the enzyme of all three peaks, and with purified, normal fibroblast enzyme. Cross-reacting material (CRM) also was identified in fibroblast lysates from normal subjects and from both forms of acid alpha-glucosidase deficiency. The amount of CRM in the adult form appeared to be significantly less than in normal cells or cells from the infantile form. Enzyme activity was demonstrated in the immune complexes of the normal and adult acid alpha-glucosidase deficiency fibroblasts, but not of the infantile form. Competition for antibody binding sites was observed between normal and both types of mutant enzymes. The findings indicate that this case of infantile acid alpha-glucosidase deficiency is the result of a structural gene mutation which causes the synthesis of a catalytically inactive (CRM-positive) enzyme protein. It appears that in the adult form, the mutation causes a reduction in the amount of the enzyme protein present in the cells.

Adult

Cell-specific differences in membrane beta-glucosidase from normal and Gaucher cells.

Two isozymes of membrane-bound beta-glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21) with activity towards 4-methylumbelliferyl-beta-D-glucopyranoside have been identified in human cells. One of these isozymes was found to have a pH optimum of 5.0, a Km of 0.4 mM and to be rapidly inactivated at pH 4.0 ("acid-labile"). The second isozyme had a pH optimum of 4.5, a Km of 0.8 mM and was stable at pH 4.0 ("acid-stable"). Cultured long-term lymphoid lines and peripheral blood leukocytes contained both isozymes while cultured skin fibroblasts contained only the "acid-stable" form in detectable amounts. The specific activity of the "acid-stable" isozyme was severely reduced in cultured skin fibroblasts, cultured long-term lines and peripheral leukocytes from patients with Gaucher's disease. The specific activity of the "acid-labile" enzyme in the latter two cell types was apparently unaffected. The beta-glucosidase activity in all three cell types examined was predominantly particulate but the enzyme could be solubilized with low concentrations of Triton X-100. The solubilized enzyme required sodium taurocholate (0.2%) for maximum activity. Solubilized beta-glucosidase did not exhibit the cell-specific differences in pH optimum and Km shown by the membrane-bound enzyme.

Cell Membrane