A patient with Klinefelter's syndrome and thalassemia intermedia.

Klinefelter's syndrome (KS) is associated with a wide spectrum of clinical features, such as tall stature, eunuchoid proportions, testes disproportionately small for the level of pubertal development, gynecomastia and behavioral problems. The association of KS with thalassemia intermedia has not been previously reported. A male patient with thalassemia intermedia was diagnosed with KS at the age of 14 years when endocrine evaluation for delayed puberty showed hypergonadotrophic hypogonadism. Thyroid function was normal; however, basal and GnRH-stimulated gonadotropin concentrations were raised while serum testosterone was low. Karyotype analysis revealed KS (47,XXY). Testosterone replacement therapy started soon after diagnosis and now at the age of 20 years the patient's height is 178.3 cm, the U/L ratio is 0.91. Testicular volume is 12 ml (Prader orchidometer) and his pubic hair is stage 4. To our knowledge this is the first case of a patient suffering from KS and thalassemia intermedia reported in the literature.

Long term audiological evaluation of beta-thalassemic patients.

OBJECTIVE: The objective of this study was to identify the incidence and to monitor the progression of hearing loss in children and young adults with beta-thalassemia major. METHODS: One hundred and four (104) patients aged 6-35 years (mean 17,2 years) participated in the study. All patients were on a regular transfusion-chelation program maintaining a mean hemoglobin level of 9.5 gr/dl. Subjects were receiving desferrioxamine (DFO) chelation treatment with a mean daily dose of 50-60 mg/kg, 5-6 days a week during the first six years of the study, which was then reduced to 40-50 mg/kg for the following eight years. Patients were followed for 8-14 years. RESULTS: Overall, 21 out of 104 patients (20.2%) presented with high frequency sensorineural hearing loss (SNHL), either unilateral or bilateral. No ototoxic factor, other than DFO, was present in any of the patients. Patients with SNHL presented with relatively lower serum ferritin levels than those with normal hearing, however, no statistically significant difference was observed. Subjects with SNHL were submitted to DFO reduction or temporary withdrawal. Following intervention, 7 out of 21 affected patients recovered, 10 remained stable and 4 demonstrated aggravation. CONCLUSION: The findings are indicative of DFO's contributing role in the development of hearing impairment. Regular audiologic evaluation is imperative in all thalassemic patients so that early changes may be recognized and treatment may be judiciously adjusted in order to prevent or reverse hearing impairment.

Urine biochemical markers of early renal dysfunction are associated with iron overload in beta-thalassaemia.

Renal dysfunction in thalassemia patients can be attributed to chronic anemia, and iron overload as well as to desferioxamine (DFO) toxicity. We analyzed the urine of 91 well-maintained homozygous beta-thalassemia patients, with no evidence of renal disease, for early evidence of kidney dysfunction by means of electrophoresis and quantitative biochemical tests. Measurement of liver magnetic resonance imaging (MRI) T2 values and serum ferritin concentration was used to estimate iron overload. In 55 of the 91 patients, urine analysis indicated signs of tubular dysfunction. The urine concentration of albumin and beta 2-microglobulin, as well as the activity of N-acetyl-beta-D-glucosaminidase (NAG), correlated positively with serum ferritin concentration and liver iron deposition, as detected by MRI T2 values. This suggested that the cause of renal dysfunction in homozygous beta-thalassemia is iron overload. On the other hand, the same urine markers did not correlate with age, indicating that chronic anemia or desferrioxamine (DFO) treatment are not related to renal dysfunction in thalassemia.

Hearing loss in children with sickle cell disease.

Hearing loss in children with sickle cell disease. Sickle cell anemia (S/S) has been associated with a high incidence of hearing loss mostly of the sensorineural type (SNHL). Twenty-four patients with sickle cell disease (13 female and 11 male; 22 patients belonging to the S/beta(+)-Thal and 2 to the S/S phenotype) with a mean age of 12.5 +/- 3.6 years and hemoglobin (Hb) levels range 6.5-11 g/dl underwent ENT examination, pure tone audiometry, speech audiometry, tympanometry, auditory reflex evaluation, tone decay test and brain auditory evoked potentials (BAEP) in order to evaluate the presence, type and degree of hearing loss. Only one patient (4.6%) who also sustained an infarct of the middle cerebral artery, demonstrated a unilateral SNHL in high tone frequencies exceeding 70 dB, as well as a prolonged III-V interpeak latency at the same side. No abnormalities were detected in the control group. These findings suggest a low incidence of SNHL in Greek SCD patients probably due to different hematological and clinical profile (S/beta(+)-Thal).

The potential antidiabetic activity of some alpha-2 adrenoceptor antagonists.

The effect of alpha-2 adrenoceptor antagonists, yohimbine and efaroxan, on the plasma glucose and insulin levels was studied in non-diabetic control, type-I (insulin-dependent) and type-II (non-insulin-dependent) diabetic rats. Pretreatment with either yohimbine or efaroxan potentiated glucose-induced insulin release in non-diabetic control rats and produced an improvement of the oral glucose tolerance and potentiated glucose-induced insulin release in type-II but not in type-I diabetic rats. Treatment with either yohimbine or efaroxan reduced the plasma glucose level and increased the plasma insulin level of non-diabetic control and type-II diabetic rats but not of type-I diabetic rats. Effects of efaroxan were more marked. Pretreatment of non-diabetic control and type-II diabetic rats with either yohimbine or efaroxan inhibited clonidine-induced hyperglycaemia and suppressed or reversed clonidine-induced hypoinsulinaemia. Also, pretreatment of these animals with either yohimbine or efaroxan enhanced the hypoglycaemic and insulinotropic effects of glibenclamide. The combination of glibenclamide and efaroxan led to a synergistic increase in insulin secretion, while that of glibenclamide and yohimbine led to an additive increase. The hyperglycaemic effect of diazoxide in non-diabetic control and type-II diabetic rats was inhibited by pretreatment with either yohimbine or efaroxan. The hypoinsulinaemic effect of diazoxide in these animals was antagonized and reversed by pretreatment with yohimbine and efaroxan, respectively. In type-I diabetic rats, there was no change in the plasma glucose and insulin levels induced by the treatment of animals with each of clonidine or diazoxide alone or in combination with either yohimbine or efaroxan. Glibenclamide produced a slight decrease in the plasma glucose level of type-I diabetic rats, at the end of the 120 min period of investigation but there was no change in the plasma insulin level. Pretreatment of these animals with either yohimbine or efaroxan produced no change in glibenclamide effects. Additionally, bath application of efaroxan or glibenclamide inhibited the relaxant effects of different concentrations of diazoxide on the isolated norepinephrine-contracted aortic strips, while the application of yohimbine produced insignificant changes. The combination of glibenclamide and efaroxan led to complete inhibition of the relaxant effects of different concentrations of diazoxide, while that of glibenclamide and yohimbine did not produce such an effect. It is concluded that yohimbine, via blockade of postsynaptic alpha-2 adrenoceptors, and efaroxan, via blockade of postsynaptic alpha-2 adrenoceptors and adenosine triphosphate-sensitive potassium channels in the pancreatic beta-cell membrane, produce insulinotropic and subsequent hypoglycaemic effects.

Sensorineural hearing loss in children with thalassemia major in Northern Greece.

Eighty eight (88) beta-thalassemic patients undergoing regular transfusion- chelation therapy with desferrioxamine (DFO) were studied for ENT problems from 1988 to 1993, as DFO has been implicated for auditory neurotoxicity. The mean age of the patients was 9.66 +/- 3.1 years, their pre-transfusion haemoglobin level was 9 +/- 2 g/dl, serum ferritin level was 2065 +/- 898 ng/ml and the daily DFO dose was 50.7 +/- 9.5 mg/kg for 5 days/week. The ENT study included, ENT examination, pure tone audiometry, speech audiometry, tympanometry, tone decay test and ABR. During this 6-year study 24/88 (27%) patients developed bilateral or ipsilateral sensorineural hearing loss in high tone frequencies, sometimes exceeding 80 dB, which was attributed to DFO toxicity. Therefore, a reduction or temporary withdrawal of DFO followed. After this intervention 12/24 patients recovered almost completely, 7/24 remained stable and 5/24 presented aggravation of their hearing loss. This study confirms the DFO induced auditory neurotoxicity and the necessity of periodical audiology control of beta-thalassemic patients for prompt diagnosis and management of this complication.

Soft drugs. 7. Soft beta-blockers for systemic and ophthalmic use.

The "inactive metabolite approach" was used to design a series of "soft" drugs derived from the acidic metabolite of metoprolol. Pharmacokinetic and pharmacodynamic properties of these novel "soft" beta-adrenoceptor antagonists were determined: half-lives in human blood ranged from 5 to 754 min. The rates of in vivo disappearance of representative slow, medium, and fast hydrolyzing esters were determined in rats. In each case rapid and quantitative conversion to the corresponding free acid was observed. This suggests a facile, one-step degradation to the predicted major metabolite. The compounds were tested for their ability to decrease intraocular pressure in a rabbit model. Five of the new compounds exerted an ocular hypotensive action comparable to or greater than that of the reference compound, timolol maleate, and with a prolonged duration of action in some cases. In contrast the new compounds showed reduced and shorter duration systemic activity. The adamantylethyl ester emerges as a potentially effective antiglaucoma agent with significantly improved site-specific activity.

Trifluorothymidine: potential non-invasive diagnosis of herpes simplex infection using 19F nuclear magnetic resonance in a murine hepatitis model.

Trifluorothymidine (TFT) is known to be concentrated in herpes simplex virus (HSV) infected cells in vitro in the form of phosphorylated derivatives. We studied a murine hepatitis model of HSV infection to determine whether this in vitro observation would also be demonstrable in vivo. Following i.v. injection of 100 or 160 mg/kg TFT, TFT was found in significantly higher concentrations in the livers of HSV-2 infected mice than in the livers of uninfected mice, mice infected with murine hepatitis virus (MHV-A59) or mice with hepatitis from carbon tetrachloride treatment. Neither altered renal function, nor altered pharmacokinetics could account for this difference. 19F Nuclear Magnetic Resonance spectroscopy readily detected the 19F from TFT in both liver extracts and whole livers, particularly at higher tissue levels, i.e. greater than 50 micrograms/g tissue. If further studies with living animals support these preliminary observations, clinical application could be pursued.

Improved delivery through biological membranes XXV. Enhanced and sustained delivery of trifluorothymidine to the brain using a dihydropyridine in equilibrium pyridinium salt type redox delivery system.

A series of alpha,alpha,alpha-trifluorothymidine (TFT) derivatives was designed and studied for brain-enhanced/specific delivery of this antiviral drug. The derivatives were esters involving one or both of TFT's hydroxy functions and N-methyl-dihydronicotinic acid. Such esters are subject to oxidative (to trigonelline) and hydrolytic metabolic transformations. Thymidine (T) was used as a model compound and the kinetics of the oxidative and hydrolytic conversion of some 16 derivatives of T and TFT were studied in various biological fluids. One compound, 3'-[O-(N-methyl-1,4-dihydronicotinoyl)]-5'-[O-(pivaloyl)]-TFT (14), was selected for in vivo studies. The compound appeared to cross the blood-brain barrier and to be converted in the brain by successive oxidative and hydrolytic processes to the 3'-[O-(N-methyl nicotinoyl)]TFT (17); this quaternary pyridinium salt was 'locked in' the brain and then further hydrolyzed in a sustained manner to release TFT, detected in measurable levels at least until 18 hours following the i.v. injection of 14. TFT was also identified as an in vitro degradation product in the different biological tissues and fluids. The results suggest that the dihydropyridine in equilibrium pyridinium salt redox delivery system can be successfully used for the brain delivery of antiviral agents that would not otherwise cross the blood-brain barrier.

Potential treatment of herpes simplex virus encephalitis by brain-specific delivery of trifluorothymidine using a dihydropyridine in equilibrium pyridinium salt type redox delivery system.

A newly described, drug-carrier delivery system in which a lipophilic derivative is enzymatically converted to a hydrophilic compound was used to treat experimental herpes simplex virus (HSV) encephalitis. Because trifluorothymidine (TFT) does not cross the blood brain barrier, the lipophilic dihydropyridine derivative 3'-(N-methyl-1, 4-dihydronicotinoyl)-5-'pivaloyltrifluorothymidine (DHTFT) was synthesized and characterized by HPLC. After intravenous administration of 20 mg/kg of DHTFT to rats, the quaternary, intermediate compound 3'-N-methyl-1,4-nicotinoyltrifluorothymidine was measured at levels of 7-8 micrograms/g brain at 1 hour and 13.5 +/- 0.8 micrograms/g brain at 4 hours. This compound had antiviral activity equivalent to that of TFT against HSV-1 in a plaque reduction assay (ID 50 = 0.5-1.0 microgram/ml), either directly or by conversion to TFT. Although survival was not prolonged in a rat model of HSV encephalitis, a statistically significant reduction in titer of HSV/g brain was achieved with daily intravenous treatment with DHTFT. TFT was not detected in brains of rats at 1 and 4 hours after intravenous DHTFT, but a low level was observed at 18 hours, 0.3 +/- 0.05 microgram/g brain. These data suggest that the lipophilic compound DHTFT or a lipophilic metabolite crossed the blood brain barrier and was converted to a quaternary compound, which accumulated in the brain and which was either active directly or was converted to TFT. The drug-carrier delivery system described here can potentially be used in the treatment of HSV or other viral encephalitides.

Electrochemical chromatographic determinations of morphine antagonists in biological fluids, with applications.

The morphine antagonists naltrexone and naloxone were extracted from plasma and urine, separated on a chromatographic column, and assayed by electrochemical detection. Optimum oxidation potentials were 0.65 V for morphine and 0.75 V for naloxone and naltrexone. Assay sensitivities were 2-5 ng/mL for plasma and 10 ng/mL for urine. The assays were applied to determine red blood cell partition coefficients of 1.83 +/- 0.15 (SD) for naltrexone and 1.49 +/- 0.27 (SD) for naloxone in a concentration range of 10-3500 ng/mL. No significant time dependence for the partitioning could be observed. Plasma protein binding in the same concentration range, determined by ultracentrifugation, was 27.7% +/- 2.5% (SD) for naltrexone and 30.1% +/- 5.1% (SD) for naloxone. The degree of protein binding did not change in the presence of morphine for morphine-antagonist ratios between 1:10 and 10:1. No concentration dependencies of red blood cell partitioning or protein binding were observed.

Mechanism of lithium action on the adrenergic function.

The intravenous injection of Lithium chloride (LiCl) in two dose levels (25 & 50 mg/kg) has led to a significant potentiation of the pressor response of rabbits to the i.v administration of both epinephrine and norepinephrine. The i.v injection of LiCl (50 mg/kg) resulted in a marked depression of the carotid occlusion reflex in rabbits. In vitro experiments revealed that LiCl (1.6 mcg/ml) and guanethidine (0.8 mcg/ml) exert the same action on the rabbit mesenteric nerve-intestine preparation and abolish the intestinal relaxation induced by electrical stimulation of the mesenteric nerve. Results confirm the assumption that Li might display a pre-synaptic, guanethidine-like, adrenergic neuronal blocking activity.

Synthesis and anti-inflammatory activity of certain new N,N'-oxamides.

Some new amides of substituted oxamic acid which embody different moieties of the anti-inflammatory drugs were prepared through two routes of synthesis. The physico-chemical properties as well as the anti-inflammatory activity of these compounds were determined. Preliminary pharmacological testing revealed the superiority of most of the screened compounds as anti-inflammatory agents with relatively low toxicity as compared with acetylsalicylic acid. Correlation between structure and biological activity was suggested.