Studies of the transition between amplified spontaneous emission and optical lasing in ultrahigh-Q polymeric micro-pedestals.

In this work, we demonstrate the properties of Rhodamine B-doped polymeric cylindrical microlasers to perform either as gain amplification devices through amplified spontaneous emission (ASE) or as optical lasing gain devices. A study based on different %wt concentrations of microcavity families with distinct geometrical features demonstrates the characteristic dependence on either gain amplification phenomena. Principal component analysis (PCA) discriminates the relationship between the main ASE and lasing properties and the geometrical aspects of the cavity families. ASE and optical lasing thresholds were found, respectively, as low as 0.2 µJcm-2 and 0.1 µJcm-2 passing the best-reported microlaser performances in literature for cylindrical cavities, even in comparison with those based on 2D patterns. Moreover, our microlasers showed ultrahigh Q-factor of ∼3 × 106, and for the first time, to the best of our knowledge, a visible emission comb constituted by above a hundred peaks at 40 µJcm-2 with a registered free spectral range (FSR) of 0.25 nm corroborated through the whispery gallery mode (WGM) theory.

Low-cost fabrication of microlasers based on polymeric micropedestals.

Our current work exploits direct laser writing (DLW) and low one-photon absorption (LOPA) in a low-cost three-dimensional optical fabrication system designed to print micrometric polymeric structures. Micropedestals were obtained by focusing a laser beam on a photoresist layer deposited on a silica glass substrate. Subsequent coating with rhodamine 6G dye allows these pedestals to function as microlasers upon optical excitation at 532 nm. Our microlasers, with a diameter of ∼53µm and a height of ∼40µm, exhibit a broad fluorescence peak in the spectral range 540-600 nm, in addition to narrow lasing peaks, exhibiting quality factors Q exceeding 2000 and a lasing threshold of ∼5µJcm-2. The observed free spectral range associated with the lasing peaks of ∼1.3nm is consistent with simulations, which we include in this paper. In addition, we present simulations for the longitudinal shift of the patterning laser spot, which occurs particularly for relatively thick photoresist layers, coupled with a large index contrast at the photoresist top surface. Such a shift could introduce errors in the resulting microfabricated structures if left unaccounted for. We hope that our work will contribute to the development of microlasers for various photonic applications, particularly if dimensions can be reduced, for on-chip optical communications and data processing.

An evaluation of different saliva collection methods for detection of antibodies against hepatitis C virus (anti-HCV).

BACKGROUND: Saliva samples can be used as an alternative fluid for against hepatitis C virus (anti-HCV) detection owing to the ease of collection and excellent acceptability. This study was conducted to optimize a commercial enzyme immunoassay (EIA) to detect anti-HCV in saliva samples. METHODS: Ninety-six individuals donated paired serum and saliva samples that were obtained, using a commercial device (Salivette) and spitting into a sterile container. Initially, elution buffer for the Salivette samples, sample volume, incubation time and temperature, and two different anti-HCV EIAs were evaluated. Using the optimized assay, three methods for cut-off calculation were also evaluated. RESULTS: A 20-fold increase in the sample volume for both collection methods was needed. Moreover, the Radim assay was the most appropriate assay for anti-HCV detection in saliva samples, and the quality parameters were increased when a ROC curve was used to determine the cut-off value. Using this optimized assay, the sensitivities, specificities, accuracies, positive and negative predictive values were above 90% for saliva obtained using both the Salivette and spitting methods. Using this assay, discordant false-negative results were obtained for only two Salivette samples and five spitting samples. The concordance kappa was 93% for the Salivette method and 86.1% for the spitting method, demonstrating excellent performance. CONCLUSIONS: Saliva samples obtained for both methods can be employed for anti-HCV detection among HCV-infected or HCV-suspected cases, but several modifications must be performed on commercial EIAs to obtain good results. Moreover, samples obtained with commercial devices are more appropriate for anti-HCV detection in saliva samples.

Microalbuminuria in essential hypertensives in treatment for hypertension.

Urinary albumin excretion (UAE) was evaluated in 26 subjects with essential hypertension and no diabetes (5 men, 21 women; 19 whites and 7 blacks), with creatinine clearance (Ccreat) > or = 75 ml/min/1.73 m2, in individualized treatment with various antihypertensive drugs. Clinical and laboratorial data were the following: mean age, 53 +/- 2 years (SEM); duration of hypertension, 14.9 +/- 2.2 years; body mass index (BMI), 26.8 +/- 0.7; arterial blood pressure, 142 +/- 4/89 +/- 3 mmHg; serum creatinine, 0.8 +/- 0.03 mg/dL; Ccreat, 99.3 +/- 3.8 ml/min/1.73 m2 and UAE, 9.3 +/- 1.5 micrograms/min. No significant difference was found when data were evaluated for gender and race. Microalbuminuria, defined as UAE > 13.9 micrograms/min, was found in 19% of the hypertensives (range: 16.3 to 28.1 micrograms/min). UAE correlated positively and significantly with systolic (r = 0.6309; P = 0.0005), diastolic (r = 0.4146; P = 0.0352), and mean blood pressure (r = 0.5000; P = 0.0093). The correlation between UAE and systolic pressure was stronger than with diastolic pressure. There was a positive and significant correlation between BMI and UAE values (r = 0.5623; P = 0.0028), and between BMI values with those of systolic (r = 0.5271; P = 0.0057) and mean blood pressure (r = 0.3930; P = 0.470). No correlation was found between UAE and age, duration of hypertension or Ccreat. Systolic, diastolic and mean blood pressures were significantly higher in microalbuminuric than in non microalbuminuric hypertensives. Obese hypertensives presented higher mean values of UAE, systolic, diastolic and mean pressures than non obese.

Prevalence of adult primary glomerular diseases: retrospective analysis of 206 kidney biopsies (1990-1993).

The prevalences of the various histopathologic forms of primary glomerular disease (PGD) were evaluated by the retrospective analysis of 206 kidney biopsies performed in a three-year period (september 1990-september 1993) in patients between 14 and 73 years of age (107 men and 99 women). Data were compared with those of a study conducted in 1985-1987, on patients of the same age group. In the present study, primary glomerular diseases showed the following prevalences: focal glomerulosclerosis, 43.2%; membranous GN, 20.4%; membranoproliferative GN, 14.1%; IgA nephropathy, 10.2%; minimal-change disease, 5.3%; mesangioproliferative GN, 2.9%; acute diffuse GN, 1.9%; rapidly progressive GN and proliferative focal segmental GN, 1% each one. Prevalences were similar in both sexes. Primary glomerular diseases were significantly more prevalent in patients with 35 years or less than in those up this age (64.6% vs 34.4%). Nonproliferative primary glomerular diseases were significantly more prevalent than the proliferative forms (68.9% vs 31.1%). The prevalences of the various histopathologic of PGD, with few exceptions, were about similar in the periods 1985-1987 and 1990-1993: the prevalences of focal glomerulosclerosis, membranous GN, IgA nephropathy and mesangioproliferative GN showed no significant differences; the prevalence of membranoproliferative GN increased (6.8% vs 14.1%), but that of type II remained very low (0.5%). Focal glomerulosclerosis was the most prevalent PGD. The prevalence of IgA nephropathy remained low, comparable with the smallest prevalences found in some of the Western countries.

Dyslipidaemias in white normotensive subjects and in white patients treated for essential hypertension.

Serum lipid profiles were evaluated in 143 white patients treated for essential hypertension (HT:31 men, 112 women, mean age 58.4 +/- 0.9 years) and in 54 normotensives (NT: 15 men, 39 women, 56.7 +/- 1.8 years). Mean values of LDL-C, HDL-C, TG and LDL-C/HDL-C ratio in hypertensives and normotensives were respectively 4.19 +/- 0.08 vs 4.01 +/- 0.16 mmol/l; 1.14 +/- 0.03 vs 1.22 +/- 0.05 mmol/l, 1.80 +/- 0.10 vs 1.30 +/- 0.06 mmol/l, and 4.0 +/- 0.1 vs 3.5 +/- 0.2; TG and ratio values of both groups differed significantly. Normotensives and hypertensives showed the same prevalence of IIa dyslipidaemia phenotype (37%). Hypertriglyceridaemic phenotypes and associated low HDL-C were more frequent in hypertensives than in normotensives (respectively 20% vs 6% and 14% vs 7%). The IIa phenotype was more prevalent in normotensive women than in men (44% vs 20%). This gender difference was absent in hypertensives (men, 39% vs women, 37%). Isolated low HDL-C was more prevalent in men than in women: NT, 20% vs 8%; HT, 16% vs 4%. IIa prevalence was greater in the age group > 50 years than in the age group < or = 50 years: NT, 22% vs 44%; HT, 12% vs 46%. The prevalence of hypertriglyceridaemic dyslipidaemias was similar in both age groups, in hypertensives (18% vs 21%) and normotensives (6% vs 6%). IIa, IIb and IV dyslipidaemias were more frequent in obese hypertensives. Positive correlations between BMI vs LDL-C and TG values were found in normotensives. In conclusion, the prevalence of dyslipidaemias was similarly high in both NT and HT groups (54% vs 64%), with some qualitative differences concerning phenotypes.

Dyslipidaemias in white and black treated essential hypertensive patients.

Serum lipid profiles were evaluated in 143 white (31 men, 112 women, aged 58.4 +/- 0.9 years) and in 75 black-individuals (16 men, 59 women, aged 52.6 +/- 1.0 years) with treated essential hypertension. Hypertension onset was earlier in the blacks than the whites (39.7 +/- 1.0 vs. 46.6 +/- 1.1 years). Duration of hypertension was similar in both races (11.8 +/- 1.0 and 12.9 +/- 1.0 years) and did not correlate with serum lipid values. Mean serum lipids, excluding HDL-C, were significantly higher in white than in black hypertensives (LDL-C 4.19 +/- 0.08 vs. 3.82 +/- 0.13; TG 1.80 +/- 0.10 vs. 1.40 +/- 0.09 mmol/l; LDL-C/HDL-C 4.0 +/- 0.1 vs. 3.6 +/- 0.2). The prevalence of dyslipidaemia was significantly higher in white than in black patients (64% vs. 52%). Types IIa, IIb and IV were more prevalent in whites and isolated low HDL-C in blacks. Obesity was found in 27% of the whites and 31% of the blacks. Hypertriglyceridaemia was more frequent in obese hypertensives of both races, but mostly among the white obese patients. Among lipid values within the normal range, the mean levels of serum lipids were similar in both races, with the exception of triglyceridaemia, which was significantly lower in black than in white hypertensives. These findings may be attributed to racial differences rather than to nutritional trends.

IgA nephropathy: acute renal failure, acute tubular necrosis, and features of postinfectious acute glomerulonephritis.

From 1976 to 1987 on our Nephrological Unit, 57 patients with IgA nephropathy (IgAN) proven by renal biopsies were found. Three of those presented with acute tubular necrosis (ATN) and glomerulitis, without extrarenal predisposing cause in two; and showed, as prominent manifestation, a severe acute renal failure syndrome (ARFS), needing dialytic treatment. All three had hematuria, which was macroscopic in two and microscopic in one. Thus the prevalence of the association of glomerulitis and ATN was about 5.2%. There was complete recovery of renal functions in all three patients, but the usual symptomatology of IgAN. Two patients presented polymorphonuclear neutrophils infiltration of glomerular capillaries and in one of them, electron-dense deposits on the epithelial side of glomerular basement membrane ("humps") were observed, as well as those identified in the mesangial area. The glomerular polymorphonuclear neutrophils infiltration and endothelial cells proliferation (cases 1 and 3), the presence of "humps" (case 1), high antistreptolysin O (ASO) titers (cases 1 and 2), and low serum complement levels (case 1), suggest the possibility that antigens able to cause postinfectious glomerulonephritis (streptococcal or not) could induce in some individuals, by another immunopathogenetic route, mixed histopathological and clinical features of IgAN and postinfectious glomerulonephritis.

[Treatment of essential hypertension and hypercholesterolemia with or without hypertriglyceridemia, with low dose of bezafibrate (200 mg/day)]. / Tratamento de hipertensos essenciais, hipercolesterolêmicos com ou sem hipertrigliceridemia, com dose baixa de bezafibrato (200 mg/dia).

Twenty patients with essential hypertension, 5 with dyslipidemia type IIa and 15 with that of type IIb, were treated with bezafibrate, 200 mg/day. As control group, 20 normo or dislipemic patients with essential hypertension receiving no hypolipidemic drugs, and chosen at random, showed no significant changes of the mean values of serum total cholesterol and triglycerides at three evaluations made in a period of about six months. Six patients were males (60 +/- 4 years) and 14 females (57 +/- 2 years). The levels of cholesterolemia and triglyceridemia were evaluated before the administration of the drug and on the 28th and 56th day of its use. The mean initial value of total cholesterol (n = 20) was 334 +/- 10 mg/dl, lowering significantly (P less than 0.01) to 274 +/- 7 mg/dl and 279 +/- 11 mg/dl. Initial triglyceridemia level (n = 15) was 544 +/- 85 mg/dl, decreasing significantly (P less than 0.01) to 234 +/- 36 and 245 +/- 36. Percentual mean decrease of cholesterolemia was respectively 16 +/- 4% and 14 +/- 5% and that of triglyceridemia was 46 +/- 8% for both evaluations. Side effects of the drug were not seen with the indicated dose. The therapy was useful to lower the dislipemic values of the essential hypertensive patients, in spite of no consistent changes in their diet and physical activity and of its use for a short period.

[Histopathologic study of primary glomerulopathies: retrospective analysis of 197 renal biopsies (1985-1987)]. / Estudo histopatológico das glomerulopatias primárias: análise retrospectiva de 197 biopsias renais (1985-1987).

The histopathological prevalence of primary glomerular diseases in patients aged 14 to 70 years (105 males, 92 females) was analysed: 140 (71%) were aged from 14 to 35 years and 57 (29%) were older than 35 years, the difference being significant (p less than 0.001). The following data were found at our Nephrological Unit: the prevalence of focal glomerular sclerosis was 37.1%; of the membranous glomerulonephritis 16.2%; of the IgA nephropathy 8.6%; of the membranoproliferative glomerulonephritis 6.1%; of the minimal change disease 5.1%. The acute diffuse glomerulonephritis, the rapidly progressive glomerulonephritis and the chronic glomerulonephritis showed the same prevalence of 4.6%, and the mesangial proliferative glomerulonephritis and the kidney in Alport's syndrome that of 3.6%. Diagnosis was not defined by renal biopsy in 6.1% of the patients. Failures to achieve diagnosis were due to biopsies with less than 5 glomeruli on optic microscopy or losses affecting the immunofluorescence procedures. It was concluded that the highest prevalence was that of the focal glomerular sclerosis, found in more than one third of the patients. It was followed by the prevalence of the membranous glomerulonephritis which occurred in about one sixth of our cases. The prevalence of IgA nephropathy, minimal change disease, membranoproliferative glomerulonephritis and of other primary glomerulopathies were low. The prevalence of focal glomerular sclerosis was significantly higher (p less than 0.001) in the younger group of patients (14-35 years) than in the older one; the same fact was seen in the prevalence of the proliferative histopathological forms of glomerulonephritis (p less than 0.025), grouping IgA nephropathy, membranoproliferative glomerulonephritis, rapidly progressive glomerulonephritis and mesangial proliferative glomerulonephritis.

Effect of posture and physical activity on urinary protein excretion by patients with glomerular proteinuria diseases.

The rate of urinary protein excretion (Uprot.V) was evaluated in 20 patients with massive proteinuria caused by various histopathological types of glomerular disease. Measurements were made during five consecutive periods: period A (overnight bed rest) and periods B, C, D and E corresponding to normal everyday upright physical activity. Mean Uprot.V was significantly lower during period A (8.2 +/- 1.3 mg/min, mean +/- SEM) than during all the periods of physical activity (11.8 +/- 1.8 mg/min). For 5/20 patients, physical activity induced a mean percent increase of 340 +/- 200% and for 11 an increase of 51 +/- 7% was observed. Only in 4 patients was the rate of urinary protein excretion unaffected or decreased on the average by -20 +/- 9% during physical activity.

Alguns efeitos da espironolactona na hipertensao arterial. / Some effects of spironolactone on arterial hypertension

Dezenove pacientes portadores de hipertensao arterial benigna leve a severa ou grave, idade media 47 anos, receberam espironolactona por 8 semanas, na dose de 200mg diarios, apos 2 semanas de placebo. O tratamento nao ocasionou alteracoes estatisticamente significativas nas taxas plasmaticas medias de Na, K, ureia, creatinina, acido urico, proteinas totais ou fracoes, glicemia e transaminases oxaloacetica e glutamico-piruvica nem nas variacoes medias do peso e pulso.As pressoes ar teriais sistolica e diastolica medias reduziram-se significativamente de 178 x 109 para 140 x 89mmHg, com os pacientes em pe, e de 173 x 109 para 143 x 87, com os pacientes deitados. Os resultados foram considerados bons ou otimos em 84% (dos pacientes em posicao em pe) e em 94% (em posicao deitada). O tratamento foi bem tolerado, nao se constatando nenhum efeito colateral severo durante o tempo de observacao. Concluiu-se que a espironolactona foi um hipotensor ativo em diferentes niveis de pressao arterial benigna, nao tendo sido levada em conta a presenca ou nao de hipo-reninemia

[Liver actinomycosis. Report of a case]. / Actinomicosis hepática. Presentación de un caso.

A case of liver actinomycosis is presented. It was diagnosed 15 days after the patient had undergone appendicectomy. Emphasis is made concerning the diagnostic difficulties in the clinical, radiological and bacteriological areas. In the present paper note is made of the low frequency of this disease in Mexico. In this case it was possible arrive at a definitive diagnosis only after the histopathological study of material obtained in a needle liver biopsy which demonstrated the sulfur granules that are characteristic of the lesion. Information is given concerning the clinical and surgical evolution as well as therapeutic management. The case is illustrated with representative roentgenograms and a microphotograph of the lesion.