Neurocutaneous melanosis: hydrocephalus and intracranialhypertension - rare case

Objective: report a case of neurocutaneousmelanosis in Belém, Pará. Case report: a 13-yearsoldboy, with history 8 months later presented paroxistic absence recurrent seizures controlledwith carbamazepine. At three years old, the seizures became generalized type, associated tonistagmus and incipient apendicular ataxia. Until 11 years old, he had neurologic exam stable,without diagnostic, when presented persistent holocranial headache, nausea, morning vomit,oftalmoparesis type III pair lesion on the right and somnolence. At general exam, it was founduncountable melanocytic nevi in his dorsum, buttocks, left arm, thorax and right shoulder. MRIstudy was performed and suggested CNS melanicytic infiltration. The patient underwentventriculoperitoneal derivation and presented good evaluation, asymptomatic.Conclusion: theearly diagnostic is very important, considering the possibility to precocious neurosurgicalintervention, allowing the increase of survival in these patients.

Objetivo: relatar um caso de melanoseneurocutanea em Belém, Pará. Relato de caso:adolescente, 13 anos de idade, gênero masculino, com história de crises convulsivasparoxísticas, tipo ausência, recorrentes, controladas com uso de carbamazepina. Aos três anosde idade, as crises tornaram-se do tipo generalizada, associada com nistagmo e ataxiaapendicular incipiente. Até 11 anos de idade, o paciente teve quadro neurológico estável, semdiagnóstico, quando apresentou cefaléia persistente holocraniana, náusea, vômitos pela manhã,sonolência e oftalmoparesia por lesão do III par craniano à direita. No exame geral, foramencontrados incontáveis nevos melanocíticos no dorso, nádegas, braço esquerdo, tórax e ombrodireito. A RNM sugeriu infiltração melanocítica do SNC. O paciente foi submetido a derivaçãoventrículo-peritoneal e apresentou boa evolução, ficando assintomático após o procedimento.Conclusão: o diagnóstico precoce é muito importante, considerando a possibilidade deintervenção neurocirúrgica precoce, permitindo o aumento da sobrevida nesses pacientes

Modeling and controller performance assessment for a switched reluctance motor drive based on setpoint relay.

This paper considers the implementation of a current control method for switched reluctance motors (SRMs) and presents a novel approach to the accurate on-line modeling of an SRM drive. A simple autotuning technique for the SRM drives using a PWM controller is considered. Furthermore, conventional PI control and Internal Model Control (IMC) are considered to validate this method and present corresponding robust control analysis for the process. The control structures are comparatively analyzed using standard robustness measures for stability and performance. The proposed PWM controller is simulated and a hardware prototype is then implemented using digital signal processor control to evaluate the method using a 12/8, three-phase SRM. The experimental results of the SRM drive model validates the performance of the current loop.

Vascular calcification: contribution of parathyroid hormone in renal failure.

Hyperphosphatemia is a driving force in the pathogenesis of vascular calcification (VC) and secondary hyperparathyroidism associated with renal failure. To test for the possible contribution of parathyroid hormone (PTH) to cardiovascular calcification, we removed the parathyroid glands from rats but infused synthetic hormone at a supraphysiologic rate. All rats were pair-fed low, normal, or high phosphorus diets and subjected to a sham or 5/6 nephrectomy (remnant kidney). Control rats were given a normal diet and underwent both sham parathyroidectomy and 5/6 nephrectomy. Heart weight/body weight ratios and serum creatinine levels were higher in remnant kidney rats than in the sham-operated rats. Remnant kidney rats on the high phosphorus diet and PTH replacement developed hyperphosphatemia and hypocalcemia along with low bone trabecular volume. Remnant kidney rats on the low phosphorus diet or intact kidney rats on a normal phosphorus diet, each with hormone replacement, developed hypercalcemia. All rats on PTH replacement developed intense aortic medial calcification, and some animals presented coronary calcification. We suggest that high PTH levels induce high bone turnover and medial calcification resembling Mömckeberg's sclerosis independent of uremia. This model may be useful in defining mechanisms underlying VC.

Decreased in vitro osteoblast proliferation and low turnover bone disease in nonuremic proteinuric patients.

Patients with proteinuria, even those with normal glomerular filtration rate, often present abnormal bone histology. We evaluated bone histology and the in vitro proliferation of osteoblasts in samples obtained from 17 proteinuric patients with primary glomerulopathies. Histomorphometric analysis of bone biopsies was performed, and bone fragments were obtained for osteoblast culture, in which we evaluated cell proliferation. In comparison to controls, patients presented lower trabecular bone volume (20.9+/-14.5% vs 26.8+/-5.9%; P=0.0008); lower trabecular number (1.7+/-0.2/mm vs 2.0+/-0.3/mm; P=0.004); and greater trabecular separation (475.5+/-96.4 microm vs 368.3+/-86.2 microm, P=0.0002). We also found alterations in bone formation and resorption: lower osteoid volume (0.9+/-0.7% vs 2.0+/-1.4%; P=0.0022); lower osteoid thickness (6.4+/-2.8 microm vs 11.5+/-3.2 microm; P<0.0001); less mineralizing surface (4.6+/-3.1% vs 13.5+/-6.0%; P<0.0001); lower bone formation rate (0.03+/-0.04 microm(3)/microm(2)/day vs 0.09+/-0.05 microm(3)/microm(2)/day; P<0.0001); and greater osteoclast surface (0.35+/-0.6 vs 0.05+/-0.1%, P=0.0016). Mean in vitro osteoblast proliferation was lower in patients than in controls (910.2+/-437.1 vs 2261.0+/-1121.0 d.p.m./well, P=0.0016). Serum concentrations of 25-hydroxyvitamin-D(3) correlated negatively with proteinuria and positively with in vitro osteoblast proliferation. Our results demonstrate that nonuremic proteinuric glomerulonephritic patients present bone structure disorder, low bone formation and high bone resorption, as well as low osteoblast proliferation.

Improvement of adynamic bone disease after renal transplantation

Low bone remodeling and relatively low serum parathyroid hormone (PTH) levels characterize adynamic bone disease (ABD). The impact of renal transplantation (RT) on the course of ABD is unknown. We studied prospectively 13 patients with biopsy-proven ABD after RT. Bone histomorphometry and bone mineral density (BMD) measurements were performed in the 1st and 12th months after RT. Serum PTH, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and osteocalcin were measured regularly throughout the study. Serum PTH levels were slightly elevated at transplantation, normalized at the end of the third month and remained stable thereafter. Bone biopsies performed in the first month after RT revealed low bone turnover in all patients, with positive bone aluminum staining in 5. In the 12th month, second biopsies were performed on 12 patients. Bone histomorphometric dynamic parameters improved in 9 and were completely normalized in 6, whereas no bone mineralization was detected in 3 of these 12 patients. At 12 months post-RT, no bone aluminum was detected in any patient. We also found a decrease in lumbar BMD and an increase in femoral BMD. Patients suffering from ABD, even those with a reduction in PTH levels, may present partial or complete recovery of bone turnover after successful renal transplantation. However, it is not possible to positively identify the mechanisms responsible for the improvement. Identifying these mechanisms should lead to a better understanding of the physiopathology of ABD and to the development of more effective treatments.

Bone involvement in idiopathic hypercalciuria.

BACKGROUND: To evaluate bone involvement in idiopathic hypercalciuria, 40 lithiasic patients and 10 controls were studied. METHODS: According to urinary calcium excretion, patients were first classified as hypercalciuric (Hca, n = 22) and normocalciuric (Nca, n = 18). The Hca patients were then subclassified according to bone densitometry (BMD) as osteopenic (HcaO, n = 10) and non-osteopenic (HCaNO, n = 12). Routine biochemistry, dietary records, bone histomorphometry. and cytokines (IL-1beta, IL-6, and TNF) production by peripheral blood mononuclear cell cultures were studied. RESULTS: There were no differences in routine biochemistry between Hca and Nca groups, except for urinary calcium. Inadequate nutrition was observed in Hca group, showing high protein (80.9% of the patients), carbohydrate (76.2%) and sodium (90%) intake. Calcium intake was low in Hca (57%) and Nca (83%) groups. IL-6 and TNF were not different between the Hca and Nca groups. IL-1beta levels were significantly high in both groups when compared to controls. IL-6 and TNF were higher in HcaO than Nca. BMD in femoral neck in HcaO was lower than in HcaNO and Nca groups. Eroded surface (ES/BS) increased in 91% of the Hca group and 36% had a mineralization defect. In the HcaO group serum PTH correlated negatively with trabecular bone volume (BV/TV) and positively with ES/BS. 1,25(OH),D3 levels correlated positively with osteoblastic surface. Calcium intake correlated positively with BV/TV and inversely with ES/BS. A negative correlation was observed between IL-6 levels and Z score of the femoral neck. CONCLUSION: Bone involvement was detected in a young population with nephrolithiasis demonstrating that a strict follow-up is necessary in order to control hypercalciuria.

Influence of the pineal gland on the physiology, morphometry and morphology of pancreatic islets in rats.

To investigate the influence of the pineal gland through melatonin secretion on the physiological and morphological parameters of pancreatic islets, we studied the plasma biochemistry and morphological and morphometric characteristics of the endocrine pancreas of male Wistar rats. The animals were distributed into five groups of ten rats each: NC - normal control group; NS -- sham-operated group; Px (25) -- pinealectomised group, studied 15--25 days after surgery; Px (70) -- pinealectomised group, studied 60-70 days after surgery; ALX - alloxan monohydrate-treated group. Data are analyzed statistically by ANOVA and by the Kruskal-Wallis test. Although there was no significant difference in plasma glucose or insulin levels between the Px (25), Px (70) and NC groups, Px (25) animals showed a tendency to increased glucose and reduced insulin levels. The ALX group showed a clear elevation of plasma glucose and a reduction of plasma insulin compared to the other groups. Morphometric analysis showed a larger pancreatic islet area and a lower pancreatic islet density in the pancreas of Px (70) animals and an increase in degenerative pathological processes in the pancreatic islets of the Px (25) and ALX groups. The present results suggest that melatonin, in addition to acting on tissue sensitivity to insulin (as reported in other studies), affects the secretory action of beta cells, as demonstrated by the morphological and morphometric changes observed in pinealectomised animals.

Effect of 17á-estradiol or alendronate on the bone densitometry, bone histomorphometry and bone metabolism of ovariectomized rats

The objective of the present study was to evaluate the effect of 17á-estradiol or alendronate in preventing bone loss in 3-month-old ovariectomized Wistar rats. One group underwent sham ovariectomy (control, N = 10), and the remaining three underwent double ovariectomy. One ovariectomized group did not receive any treatment (OVX, N = 12). A second received subcutaneous 17á-estradiol at a dose of 30 æg/kg for 6 weeks (OVX-E, N = 11) and a third, subcutaneous alendronate at a dose of 0.1 mg/kg for 6 weeks (OVX-A, N = 8). Histomorphometry, densitometry, osteocalcin and deoxypyridinoline measurements were applied to all groups. After 6 weeks there was a significant decrease in bone mineral density (BMD) at the trabecular site (distal femur) in OVX rats. Both alendronate and 17á-estradiol increased the BMD of ovariectomized rats, with the BMD of the OVX-A group being higher than that of the OVX-E group. Histomorphometry of the distal femur showed a decrease in trabecular volume in the untreated group (OVX), and an increase in the two treated groups, principally in the alendronate group. In OVX-A there was a greater increase in trabecular number. An increase in trabecular thickness, however, was seen only in the OVX-E group. There was also a decrease in bone turnover in both OVX-E and OVX-A. The osteocalcin and deoxypyridinoline levels were decreased in both treated groups, mainly in OVX-A. Although both drugs were effective in inhibiting bone loss, alendronate proved to be more effective than estradiol at the doses used in increasing bone mass

Effect of 17beta-estradiol or alendronate on the bone densitometry, bone histomorphometry and bone metabolism of ovariectomized rats.

The objective of the present study was to evaluate the effect of 17beta-estradiol or alendronate in preventing bone loss in 3-month-old ovariectomized Wistar rats. One group underwent sham ovariectomy (control, N = 10), and the remaining three underwent double ovariectomy. One ovariectomized group did not receive any treatment (OVX, N = 12). A second received subcutaneous 17beta-estradiol at a dose of 30 microg/kg for 6 weeks (OVX-E, N = 11) and a third, subcutaneous alendronate at a dose of 0.1 mg/kg for 6 weeks (OVX-A, N = 8). Histomorphometry, densitometry, osteocalcin and deoxypyridinoline measurements were applied to all groups. After 6 weeks there was a significant decrease in bone mineral density (BMD) at the trabecular site (distal femur) in OVX rats. Both alendronate and 17beta-estradiol increased the BMD of ovariectomized rats, with the BMD of the OVX-A group being higher than that of the OVX-E group. Histomorphometry of the distal femur showed a decrease in trabecular volume in the untreated group (OVX), and an increase in the two treated groups, principally in the alendronate group. In OVX-A there was a greater increase in trabecular number. An increase in trabecular thickness, however, was seen only in the OVX-E group. There was also a decrease in bone turnover in both OVX-E and OVX-A. The osteocalcin and deoxypyridinoline levels were decreased in both treated groups, mainly in OVX-A. Although both drugs were effective in inhibiting bone loss, alendronate proved to be more effective than estradiol at the doses used in increasing bone mass.

Dynamic tests of parathyroid hormone secretion using hemodialysis and calcium infusion cannot be compared.

BACKGROUND: Extracellular Ca++ concentration [Ca++] and parathormone (PTH) are related by a sigmoidal function. The set point of the control system is the [Ca++] that produces a half-maximal inhibition of PTH secretion. Whether or not this set point is abnormal in patients with chronic renal failure (CRF) and secondary hyperparathyroidism (SHP) is controversial. METHODS: We investigated whether the way [Ca++] is varied [hemodialysis (HD) or calcium gluconate/sodium citrate infusions (INF)] and the way the curve is constructed (four-parameter model or adapted four-parameter, created by Felsenfeld) could influence this set point. We performed dynamic tests of PTH secretion in 12 patients with CRF and SHP during either HD or INF. Both the four-parameter model or adapted four-parameter methods were used, creating four combinations: (a) hypocalcemia and hypercalcemia induced during HD, calculated by Brown's formula (HDB); (b) hypocalcemia and hypercalcemia induced during HD, calculated by Felsenfeld's formula (HDF); (c) hypocalcemia and hypercalcemia induced during infusion, calculated by Brown's formula (INFB); and (d) hypocalcemia and hypercalcemia induced during infusion, calculated by Felsenfeld's formula (INFF). RESULTS: The set points obtained with HDB correlated perfectly with those obtained with HDF (R2 = 0.999). A similar relationship was found between INFB and INFF (R2 = 0.9997). In contrast, there was no correlation between either HDB and INFB (R2 = 0.0157) or HDF and INFF (R2 = 0.0204). CONCLUSIONS: These findings indicate that the calculated [Ca++] set point in patients with CRF and SHP is determined by the way [Ca++] is varied, rather than by the mathematical model used to generate the curves. Further studies are needed to determine the differing physiological mechanisms triggered by HD and INF and the way they influence [Ca++] homeostasis in this setting.

Histochemical staining of bone aluminum: comparison of aluminon and acid solochrome azurine and their correlation with bone aluminum content.

Aluminum (Al) may be a pathogenic factor in dialysis associated osteodistrophy. Aluminon and Acid Solochrome Azurine have been used for the detection of Al deposits in bone. We compared Aluminon and Acid Solochrome Azurine stains in normal (N) and uremic (U) rats. Both received intraperitoneal injections of aluminum chloride (AlCl3), until a cumulative dose of 5 mg/Al (NAL5; UAL5) or 30 mg/Al (NAL30; UAL30). The control groups received an equal volume of distilled water by means of intraperitoneal injections. Histomorphometric analysis showed that formation parameters (osteoid volume-OV/BV and osteoid surface-OS/BS), were significantly greater in the uremic groups than the control groups. In addition, the aluminum intoxication increased these values. When we compared the aluminum deposits in the undecalcified bone detected by both staining methods, we observed that Acid Solochrome Azurine was more sensitive than Aluminon in the normal renal function group and uremic treated with 5 mg of AlCl3. All our results were compared with atomic absorption spectrophotometry, showing that Al content presented a positive correlation with Aluminon stain in U and N rats, nevertheless it was not observed using Acid Solochrome Azurine stain. We conclude that histochemistry is important in diagnosing and monitoring aluminum bone disease.

Possible role of an adrenal parasite reservoir in the pathogenesis of chronic Trypanosoma cruzi myocarditis.

The possible contribution of parasitism of the central vein of the adrenal gland (CVAG) to chronic Trypanosoma cruzi myocarditis was assayed by comparing the occurrence of nests of amastigotes in the left ventricular myocardium (LVM) and determining the number and extent of areas of focal leucocyte exudate (FLE) in Chagas disease patients with and without CVAG parasitism. The frequency of occurrence of T. cruzi nests in the LVM, as well as the FLE number and area, were greater among patients with CVAG parasitism. We therefore suggest that CVAG parasitism plays a role in the onset and intensity of chronic T. cruzi myocarditis.

[Comparison of parasitology of the central vein of the adrenal gland and the other tissues in chronic chagas disease]. / Comparação do parasitismo da veia central da supra-renal com o de outros tecidos em chagásicos crônicos.

By morphological and morphometric analyses of serial sections the occurrence of T. cruzi nests in the central vein and in the parenchyma of adrenal glands, in the left ventricular wall and in the inferior vena cava wall in chronic Chagasic patients was studied. Of 36 cases 50% showed parasites in the adrenal central vein wall (total 29 nests), 3.1% showed parasites in the vena caval wall (only I nest) and 16.8% we found parasites in the myocardiocytes (total 23 nests). The density of parasites measured in the nests for each 100mm2 of the tissue examined, was 0.585 for the adrenal vein, 0.001 for the vena cava and 0.01 for the myocardium. No nest was found in 269103.1mm2 of adrenal parenchyma. Although the central vein area examined was smaller, it showed the largest frequency of T. cruzi nests. Since a basic difference between these tissues is the great quantity of corticoids in the blood of the adrenal central vein, this prevalence may be because of this hormonal ambient, which with its immunosuppressor and anti-inflammatory effects could help T. cruzi survival.

Effects of GABA natriuresis induced centrally by cholinergic stimulation.

Sodium and potassium excretion and urine output have been studied in rats following water loading and intracerebroventricular (i.c.v.) injection of isotonic saline (NaCl-0.15M), gamma-amino butyric acid (GABA), picrotoxin, carbachol, GABA plus picrotoxin, GABA plus carbachol and GABA plus atropine. GABA injection decreased sodium and potassium excretion. Picrotoxin or carbachol injection elicited natriuresis and kaliuresis. GABA injection decreased the effects of the carbachol and atropine injection decreased the effects of the GABA on sodium and potassium excretion. These results suggest an interaction between gabaergic and cholinergic pathways in the control of sodium and potassium excretion.