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Biomedical subjects

M Castellano

Publications and source records attributed to M Castellano.

At least 91 records · Page 5Linked to original sources
PubMed1994

Arteriovenous fistulae following hair transplantation: collective review and report of a case.

Hair transplantation has become one of the most common cosmetic procedures in men. Complications are reported to be rare. Eight cases of arteriovenous fistulae following the procedure have been recorded in the literature, occurring anywhere from a few weeks to several months after the transplantation. This presentation, the ninth case, is of a 33-year-old man whose procedure was performed in a dermatology clinic and who first saw signs of an enlarged, pulsating blood vessel in the temporal region some 7 weeks later. A photograph of the lesion is presented and the method of treatment of the fistula is described.

Adult↗
PubMed1994

Cardiac norepinephrine, beta-adrenoceptors, and Gi alpha-proteins in prehypertensive and hypertensive spontaneously hypertensive rats.

In spontaneously hypertensive rats (SHR), cardiac adenylate cyclase is desensitized owing to down-regulation of myocardial beta-adrenoceptors and an increase in Gi alpha. We wished to determine whether these biochemical alterations in the beta-adrenoceptor-adenylate cyclase system precede development of hypertensive cardiac hypertrophy or whether this increase occurs only in later stages of the syndrome and represents a secondary phenomenon. Myocardial samples from 5- and 13-week-old SHR and age-matched Wistar Kyoto rats (WKY) as controls were studied. Cardiac beta-adrenoceptors were studied with [125I]cyanopindolol ([125I]ICYP] as radiolabeled ligand. beta-Adrenoceptor subtypes were determined with the beta 1- and beta 2-selective antagonists CGP 207.12A and ICI 118.551, respectively. Gi alpha proteins were measured with the pertussis toxin-catalysed [32P]ADP ribosylation. Myocardial norepinephrine (NE) content was investigated with high pressure liquid chromatography. In myocardial membranes of 13-week-old SHR, the number of total beta-adrenoceptors as well as beta 1- and beta 2-adrenoceptors was reduced. No difference was observed between SHR and WKY, at age 5 weeks. The nonionic detergent Lubrol PX at 0.5% (vol/vol) increased the amount of detectable Gi alpha by a factor of 14. Under these optimal conditions, Gi alpha was increased by 30% in 13-week-old SHR, but not 5-week-old SHR as compared with WKY. Myocardial NE content was increased by 25-35% in both 5- and 13-week-old SHR as compared with WKY. The results showed that nonspecific beta-adrenoceptor downregulation and an increase in Gi alpha occurs in hypertensive cardiac hypertrophy of SHR. In the prehypertensive stage, these changes were not observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed1994

Delayed development of hypertension after short-term nitrendipine treatment.

In this study we evaluated the delayed effects of a calcium entry blocker on blood pressure and on vascular structural and functional alterations in mesenteric resistance arteries of spontaneously hypertensive rats (SHR). The calcium entry blocker nitrendipine was administered (30 mg/kg per day) according to three different schedules: in one group of SHR from 4 to 8 weeks of age (n = 12), in a second group from 8 to 12 weeks of age (n = 12), and in a third group from 4 to 12 weeks of age (n = 12). Twelve untreated SHR and 12 untreated Wistar-Kyoto rats served as controls. Half the animals of each group were killed at 13 weeks, and the remaining were killed at 38 weeks. After death, relative left ventricular mass was calculated. Vascular morphology and function (responses to norepinephrine and acetylcholine) in mesenteric small arteries were then assessed using a micromyographic technique. Nitrendipine treatment delayed the development of hypertension and determined the regression of structural alterations of mesenteric resistance arteries in SHR. These favorable effects were maintained for several weeks after treatment withdrawal, provided that treatment was started at 4 weeks of age. Considering the functional alterations of mesenteric arteries in SHR (responses to norepinephrine and acetylcholine), nitrendipine treatment determined an improvement of both these dysfunctions as long as reductions of the media-to-lumen ratio and blood pressure, respectively, were maintained.

Animals↗
PubMed1994

Beta-adrenergic neuroeffector mechanisms in cardiac hypertrophy of renin transgenic rats.

We studied neuroeffector defects in hypertrophied myocardium of hypertensive transgenic rats harboring the mouse Ren-2d gene. In transgenic rats, epinephrine and neuropeptide Y concentrations were reduced. A heterologous desensitization of adenylyl cyclase was observed, which was accompanied by a downregulation of beta 1-adrenergic receptors, an increase of inhibitory G protein alpha-subunits, and a mildly depressed catalyst activity of adenylyl cyclase, whereas the bioactivity of stimulatory G protein alpha-subunits and beta 2-adrenergic receptors was unchanged. Desensitization of adenylyl cyclase was accompanied by a reduced positive inotropic response to isoproterenol, whereas the effect of Ca2+ was unchanged. We conclude that sympathetic neuroeffector defects occur in transgenic rats similar to those observed in human failing myocardium. These alterations occur in the stage of hypertrophy and could contribute to contractile dysfunction in later stages.

Adenylyl Cyclases↗
PubMed1994

Cardiovascular structural changes and calcium antagonist therapy in patients with hypertension.

Regression of cardiovascular structural changes is a main goal of antihypertensive treatment. Two recent meta-analyses of relatively small noncomparative studies have suggested that angiotensin-converting enzyme (ACE) inhibitors may be more effective than other classes of drugs in inducing regression of left ventricular hypertrophy (LVH). The effect of different antihypertensive drugs on arteriolar structural changes has not yet been properly investigated. The aim of this study was to evaluate the effect of 6 months of treatment with amlodipine (5-10 mg o.d.) or enalapril (10-20 mg o.d.) on blood pressure (BP) (ambulatory monitoring), heart rate (HR), LV mass and function (M-mode echo, two-dimensionally guided), forearm minimal vascular resistance (min VR = BP/max blood flow-venous occlusion plethysmography, taken as an index of vascular structural changes) in 24 hypertensive patients in a comparative single-blind, randomized study, with blind reading of echocardiograms and plethysmographic tracings. After 6 months of treatment with amlodipine 5-10 mg o.d., significant reductions in LV mass index (p = 0.004) and forearm min VR (p = 0.02) were observed. Before and during treatment, LV systolic function, both at rest and during stress (handgrip test), evaluated by fractional shortening as related to end-systolic stress, was in every case within 95% confidence limits calculated in normal subjects. Similar results were observed with enalapril. No significant differences were observed for Doppler indices of diastolic filling after 6 months of treatment with either drug. These results indicate that a significant regression of structural changes in the heart and in the small resistance vessels can be observed after long-term treatment with amlodipine in essential hypertensive patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Rectal prolapse: etiopathogenetic and therapeutic problems in psychiatric patients].

Rectum prolapse is a pathological condition which has long been considered as rare but whose occurrence has been progressively increasing in the past decades. There still exists a degree of uncertainty as to the disease etiopathology: moreover the exact relationship between rectum prolapse and psychic disorders which have been found in up to 50% of the patients with prolapse has not been clarified. Neither on the therapeutic level is there a common opinion as to the ideal surgical approach and over one hundred techniques have been suggested for the surgical correction of the prolapse. A study has been carried out on 10 patients suffering from psychiatric pathology of different kinds (oligophrenia, schizophrenic psychosis), hospitalized at Istituti Ospedalieri Opera Don Uva in Bisceglie. They suffered from complete rectum prolapse and underwent surgical intervention. In this study the etiopathogenetic problems of prolapse are investigated according to recent developments, with particular reference to the very peculiar implications they have in the psychiatric patient. Finally the surgical techniques correctly used and their possible application in the psychiatric patient are examined.

Adult↗
PubMed1994

The human A-myb protein is a strong activator of transcription.

The A-myb gene belongs to the family of the c-myb proto-oncogene. We report here the cloning from a B lymphocyte cDNA library of the previously missing 3' half of the human A-myb cDNA, thus closing the previously still incomplete open reading frame. Analysis of the homologies between the different myb proteins reveals four domains of high conservation. We show, using a polyclonal rabbit antibody, that the 90 kd human A-myb protein is nuclear and that it activates transcription from the KHK-CAT reporter 6-10 times more strongly than c-myb in NIH3T3 cells. The transactivating function of A-myb depends on the presence of the myb binding site in the reporter, and on both the DNA binding and acidic domains of the A-myb protein. The bacterially expressed protein protects the myb binding sites of the reporter in footprint experiments. Binding of the A-myb protein is shown in gel retardation assays to be specific for the classical c-myb recognition sequence PyAACG/TG. In addition, like c-myb, A-myb binds more strongly to the MIM-A synthetic oligonucleotide that carries the TAACGG sequence than to the MBS-I oligonucleotide containing TAAGTG. Finally, DNA binding activity is demonstrated to require the N-terminal portion of the protein containing the three tandem repeats of amino acids conserved in all myb proteins. We have thus shown that the A-myb protein is a strong activator of transcription and that this activity depends on both the DNA-binding and acidic domains.

3T3 Cells↗
PubMed1994

The myb oncogene family of transcription factors: potent regulators of hematopoietic cell proliferation and differentiation.

The myb family of genes includes the virally encoded v-myb oncogene, the c-myb protooncogene from which it is derived, and two structurally related genes, B-myb and A-myb. C-myb is most highly expressed in hematopoietic cells and its oncogenic activation leads to transformation, primarily of myeloid cells. Several lines of evidence suggest that c-myb functions in regulating both the proliferation and differentiation of hematopoietic cells of different lineages, including early progenitors. The mechanisms of action and the regulation of expression of c-myb and v-myb will be described. The possible role of the B-myb and A-myb gene products will also be discussed.

Base Sequence↗
PubMed1993

Hypothalamic-pituitary-gonadal function in prepubertal boys and girls with chronic renal failure.

Hypothalamic-pituitary-gonadal function was evaluated in 24 prepubertal children with chronic renal failure (CRF). Among the 17 boys, 5 were receiving conservative treatment and four long-term dialysis. Another eight boys were studied 6 months to 3.3 years after renal transplantation; their ages ranged from 5 years 8 months to 15 1/2 years. Among the girls, two patients were receiving conservative treatment and five long-term dialysis; their ages ranged from 3 1/2 years to 11 years 2 months. In boys with CRF, but not in those after transplantation, mean serum follicle-stimulating hormone 60 minutes after administration of gonadotropin releasing hormone (GnRH) was lower than in 18 control prepubertal boys (mean +/- SD: 2.53 +/- 1.34 vs 6.25 +/- 2.84 IU/L, respectively; p < 0.01). Testosterone steroidogenic capacity after 1 week of stimulation with human chorionic gonadotropin and androgen sensitivity (percentage of decrease of serum sex hormone-binding globulin 1 week after intramuscular administration of testosterone enanthate) were normal. In girls, no difference between those with CRF and a control group of 19 girls was found after intravenous administration of GnRH. However, after intramuscular administration of GnRH agonist, serum follicle-stimulating hormone concentration was lower in girls with CRF than in control girls (p < 0.02); six of seven control girls had an increase of serum estradiol to more than 55 pmol/L, whereas three of seven girls with CRF had no response, and serum follicle-stimulating hormone failed to increase after GnRH agonist therapy in two of these patients. We conclude that hypothalamic-pituitary function is not normal in some prepubertal boys and girls with CRF, particularly in those with low serum albumin concentrations. On the other hand, testicular and ovarian steroidogenic capacity is not impaired, and the biologic response to androgens in boys is preserved.

Adolescent↗
PubMed1993

Effects of transdermal nitroglycerin in combination with an ACE inhibitor in patients with chronic stable angina pectoris.

We have previously shown that transdermal nitroglycerin may induce an increase in the activity of the adrenergic and the renin-angiotensin-aldosterone systems (SRAA) in patients with chronic stable angina pectoris (SA); when the activation of these systems is more pronounced, the antianginal effect of this drug seems to be reduced. The aim of this study was to evaluate the antianginal efficacy of transdermal nitroglycerin administration (TTS-NG 10 mg.24 h-1) in combination with an ACE inhibitor without sulphydryl groups (BNZ, benazepril 10 mg b.i.d.) in respect to placebo, or to TTS-NG or BNZ administered as monotherapy. Twenty-four patients (21M, 3F) were admitted to this multicentre, randomized, double-blind, latin square, placebo-controlled study. Patients received all the treatments (placebo, TTS-NG, BNZ and BNZ + TTS-NG) each for one week; at the end of each week patients performed two exercise tests 2 and 22 h post-dosing. Two hours post-dosing, exercise duration at 1 mm ST depression was significantly increased in respect to placebo during TTS-NG (P < 0.05) and TTS-NG + BNZ (P < 0.05) treatments. Two hours post-dosing, exercise duration at peak exercise was also increased in respect to placebo during TTS-NG (P < 0.05) and TTS-NG + BNZ (P < 0.05); 22 h post-dosing the increase in exercise duration was significant only during TTS-NG + BNZ treatment (P < 0.05) in respect to placebo, but not during TTS-NG given alone. Rate-pressure product at 1 mm ST depression was significantly increased 2 h post-dosing during TTS-NG treatment (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗
PubMed1993

Gene expression of cardiac beta 1-adrenergic receptors during the development of hypertension in spontaneously hypertensive rats.

OBJECTIVE: To study adrenergic receptors in the heart tissues of genetically hypertensive rats by evaluating the gene expression and the membrane protein density of beta 1-adrenergic receptors using steady-state messenger RNA (mRNA) levels and a radioligand binding assay, respectively. DESIGN: We compared prehypertensive (5-week-old) and early-hypertensive (13-week-old) spontaneously hypertensive rats (SHR) with age-matched Wistar-Kyoto (WKY) normotensive control rats. METHODS: Polyadenylated RNA was extracted from individual hearts and analysed by the slot-blot technique using a beta 1-adrenergic receptor complementary DNA probe. beta-Adrenergic receptors in myocardial membranes were studied by radioligand binding assay using [125I]-cyanopindolol and the beta 1- and beta 2-selective antagonists CGP 207.12A and ICI 118.551, respectively. RESULTS: beta 1-Adrenergic receptor mRNA levels were slightly higher, and membrane protein density was similar in prehypertensive SHR and age-matched WKY rats. However, both beta 1-adrenergic receptor mRNA levels and beta 1-adrenergic receptor density were lower in the hypertensive SHR than in the control rats. beta 1-Adrenergic receptor mRNA was significantly reduced in older rats of both strains, and this reduction was most evident in the SHR. CONCLUSIONS: The absence of downregulation of beta 1-adrenergic receptors in young SHR, despite published data indicating a higher cardiac noradrenaline turnover than in WKY rats, may suggest that the cardiac hyperadrenergic activity observed in prehypertensive SHR is maintained, at least in part, by the participation of peripheral, postsynaptic component(s) involving beta 1-adrenergic receptor dysregulation. In addition, the present data suggest that the previously reported evidence of an age-related decrease in cardiac beta 1-adrenergic receptors in rats may be determined at the transcriptional level.

Animals↗
PubMed1993

Effect of antihypertensive treatment on daytime and nighttime power spectral analysis of heart rate.

Power spectral analysis of heart rate may provide useful information about cardiac neural activity. The aim of this study was to evaluate cardiac sympathetic and parasympathetic activity, as assessed by power spectral analysis of heart rate, in hypertensive patients before and after antihypertensive treatment. In 14 hypertensive patients and in 7 normotensive subjects 24 h Holter electrocardiogram monitoring was performed under basal conditions and after 6 months of treatment with nifedipine (n = 7) or enalapril (n = 7). Sequences of 512 RR intervals were taken for the evaluation of power spectral analysis (autoregressive method); absolute and normalized power spectral density of the peak at 0.10 Hz (low frequency peak: LF) and at 0.25 Hz (high frequency peak: HF), as well as their ratio (index of sympatovagal interaction: SVI) were calculated. Under basal conditions SVI was significantly decreased from daytime to nighttime in normotensives, while no change was observed in hypertensive patients. In all hypertensive patients a reduction of SVI during nighttime in respect to basal values was observed after treatment. SVI during nighttime was significantly reduced with both nifedipine and enalapril, while SVI during daytime was slightly increased during nifedipine treatment, and significantly reduced during enalapril treatment. Systolic and diastolic arterial pressure as well as left ventricular mass index were significantly reduced with both treatments. In conclusion, long term treatment with nifedipine or enalapril seems to be able to restore an impaired daytime to nighttime SVI modulation in hypertensive patients, even considering the potential limitations of power spectral analysis of heart rate.

Adult↗
PubMed1992

Detection of a transcriptional block in the first intron of the human c-myb gene.

The levels of expression of the murine c-myb gene, like those of several other proto-oncogenes, can be controlled by a block of transcriptional elongation within the first intron of the gene. We have performed run-off experiments with double- and single-stranded probes on the myelomonocytic cell line U937, and show that this mechanism of transcriptional arrest is true also for the human c-myb gene and takes place within the first intron. Furthermore, we have sequenced the entire first intron of the human c-myb gene, and discuss the sequence structure in relation to its putative ability to arrest RNA polymerase II and its high degree of homology with the equivalent murine intron.

Base Sequence↗
PubMed1992

Transdermal nitroglycerin efficacy in patients with chronic stable angina pectoris as related to sympathetic and renin-angiotensin-aldosterone activity.

The aim of this study was to evaluate the acute effects of transdermal nitroglycerin on the sympathetic and renin-angiotensin-aldosterone systems activity, in a group of patients with stable exercise induced angina pectoris. Eighteen outpatients (15M, 3F, age range 47-65 years) were included in this double-blind, randomized, crossover trial comparing the antianginal effects of a transdermal system delivering 20 mg.day-1 of nitroglycerin to an identical placebo. Plasma renin activity, plasma aldosterone and catecholamine concentrations were measured in resting basal conditions and at 4, 8, 24, and 32 h post-dosing. Patients were subdivided in two groups according to the increase in exercise duration after patch application greater than 30% (responders, n = 8) and less or equal to 30% (non-responders, n = 10) in respect to placebo. In responders plasma norepinephrine was slightly increased during transdermal nitroglycerin administration in comparison to placebo while no change was observed in plasma adrenaline and aldosterone concentrations and in plasma renin activity. In non-responders plasma norepinephrine levels significantly increased during nitroglycerin treatment in comparison with placebo. Multiple comparisons showed that this increase was significant at 4, 8 and 24 h post-dosing. Plasma epinephrine and aldosterone concentrations and plasma renin activity were also increased after nitroglycerin administration. In the population as a whole, a significant inverse correlation was found between the percent increase in exercise duration (active drug vs placebo) and the absolute values of plasma norepinephrine and aldosterone, 4 h post-dosing.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗
PubMed1992

Endocrine disorders in 66 suprasellar and pineal tumors of patients with prepubertal and pubertal ages.

Tumor oncotypes, initial symptoms and endocrine disturbances before and/or 1 month after surgery were studied in 66 patients with prepubertal and pubertal ages having suprasellar or pineal intracranial tumors. Neoplasms found in patients of prepubertal age were: 15 craniopharyngiomas (CRA), 24 neuroepithelial-cell-derived tumors (NEC), 5 germ cell tumors (GERM) and 4 other lesions (OTHER). In patients of pubertal age, there were 7 CRA, 7 pituitary tumors (PIT), 2 NEC, 1 GERM and 1 OTHER. Approximately 90% of patients had visual abnormalities as one of the initial signs and symptoms, while 59% had increased intracranial pressure. Short stature was observed in only 10% of patients. Before surgery, somatotropic function was found to be deficient (by 2 pharmacological tests) in 90-100% of patients with CRA, PIT or GERM and in 40% of patients with NEC. Overt hypothyroidism was found in 5-25% of CRA, NEC or GERM but in 40% of PIT. Abnormal TSH responses to TRH were observed in 64% of CRA and in 29% of NEC. Low basal serum cortisol was found in 21 or 6% of patients with CRA or NEC, but in 100 or 60% of patients with PIT or GERM, respectively. Diabetes insipidus was diagnosed in 13.6% of all patients. Surgery produced few additional disturbances in endocrine function, except for the incidence of diabetes insipidus which was doubled. Gonadotropic deficiency was found in most patients of pubertal age with CRA and PIT. They were readily differentiated by the high prolactin or growth hormone (GH) levels of the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗