Steady-state PERG adaptation: a conspicuous component of response variability with clinical significance.

PURPOSE: To investigate within-test variability of the steady-state PERG (SS-PERG). METHODS: SS-PERGs were recorded in response to black-white horizontal gratings (1.6 cycles/deg, 98% contrast, 15.63 reversals/s, LED display, 25 deg square field, 800 cd/sqm mean luminance) using skin electrodes. PERG and noise (± reference) signals were averaged over 1024 epochs (~ 2.2 min) and Fourier analyzed to retrieve SS-PERG amplitude and phase. SS-PERGs were split into 16 partial averages (samples) of 64 epochs each, and corresponding amplitudes and phases combined in polar coordinates to assess their dispersion (within-test variability). To assess time-dependent variability, samples were clustered in four successive time segments of ~ 33 s each. Amplitude adaptation was defined as amplitude difference between initial and final clusters, and PERG phase adaptation as the corresponding phase difference. To determine the dynamic range of SS-PERG adaptation, recording was performed in normal controls of different age (n = 32) and patients with different severity of optic nerve dysfunction (early manifest glaucoma, EMG, n = 7; non-arteritic ischemic optic neuropathy, NAION, n = 5). RESULTS: Amplitude adaptation was largest in younger controls (amplitude adaptation ÷ noise, SNR = 9.5, 95% CI 13.1, 5.9) and progressively decreased with increasing age (older subjects, SNR = 5.5, 95% CI 9.2, 1.8) and presence of disease (EMG: SNR = 2.4, 95% CI 3.5, 1.4; NAION: SNR = 1.9, 95% CI 6.5,-2.2). In 11 young subjects, amplitude adaptation was repeatable (test-retest in two sessions a week apart; intraclass correlation coefficient = 0.59). Phase adaptation was not significantly different from zero in all groups. CONCLUSIONS: SS-PERG adaptation accounts for a sizeable portion of the within-test variability. As it has robust SNR, sufficient test-retest variability, and is altered in disease, it may have physiological and clinical significance. This study suggests that SS-PERG protocols should include adaptation in addition to SS-PERG amplitude and phase/latency.

Oral health in children with acute lymphoblastic leukaemia: before and after chemotherapy treatment.

AIM: To evaluate changes in the oral health status of children under the age of 14 years with acute lymphoblastic leukaemia (ALL) attending a cancer centre before and after chemotherapy treatment. MATERIALS AND METHODS: A total of 32 children with ALL without distinction of gender were selected for study. The oral cavity of the patients was evaluated before the induction stage and 17 days later. Clinical evaluation of the submandibular, submental, and cervical lymph nodes was performed. Saliva samples were collected during the early morning hours. Bacterial plaque was assessed by using the Silness and Löe plaque index (SLPI) and gingiva status was evaluated with the gingival Löe and Silness index (GLSI). The WHO toxicity oral scale was used to record the degree of oral mucositis. The resulting data were analysed with McNemar's test, t test (for related samples), and Wilcoxon test. RESULTS: There were statistically significant differences for palpable lymph nodes, paleness of oral mucosa, and ecchymoseis, respectively, P ≤ 0.000, P = 0.03, and P = 0.01, with these manifestations decreasing significantly after treatment. Incipient gingivitis had frequencies of 71.9% and 75% before and after treatment, respectively. The mean SLPI score declined significantly from 1.16 ± 0.52 (before treatment) to 0.56 ± 0.36 (after treatment) (P < 0.000); salivary flow increased significantly from 0.54 ± 0.34 to 1.22 ± 1.07 after chemotherapy treatment (P < 0.00). Oral mucositis was present in 24 children (75%) with a 1-2 severity level. CONCLUSIONS: After chemotherapy treatment, there were changes in the oral conditions of children with ALL. Some manifestations decreased after treatment, whereas in others increased.

Impaired glucose metabolism in hypertensive patients.

We have studied glucose tolerance under carefully controlled conditions in 79 patients with arterial hypertension. The results show that, in patients with arterial hypertension but without clinical diabetes mellitus, the glucose tolerance was abnormal in 77.3% and normal in 22.3%. The corresponding figure in the control group of normotensive subjects was 0%. In each test the responses to glucose administration were analyzed by plotting the logarithm of the blood glucose concentration against time. For the points between 60 and 120 min, corresponding to the periods following glucose administration, a linear relationship was obtained and showed a decline at an exponential rate, as noted by other observers. An estimate of the volume of distribution of glucose was obtained as follows. Values observed in hypertensives with a pathological percent fall in blood glucose per minute (Kg) were 29.8 +/- 12.0 (mean +/- SD) liters and those in normal subjects with normal Kg values had a mean of 14.35 +/- 2.98, the difference being highly significant (p less than 0.0001). The results of the theoretical glucose concentration are also presented. Those obtained from subjects with normal Kg values (359.0 +/- 58.4 mg/dl) are significantly higher than in subjects with pathological Kg values (257.6 +/- 51.3 mg/dl; p less than 0.0001). All patients with either pathological or normal Kg values had normal glucose concentration levels, fasting blood sugar and no glucose in the urine specimen. The difference between pathological Kg values (107.0 +/- 25.8 mg/dl) and normal Kg values (90.6 +/- 13.0 mg/dl) was not found to be statistically different (p greater than 0.05). The distribution and means of glucose half time in controls with normal Kg values and hypertensives with pathological Kg values were: 63.5 +/- 11.5 and 137.8 +/- 48.1 min, respectively. The difference between normal and pathological Kg values being statistically significant at a confidence level above 99.5%. We also studied the free glucose pool at zero time. A significantly higher level was found in hypertensives with pathological Kg values, again indicating an impairment in glucose metabolism in this group: 90.6 +/- 26.5 vs. 65.0 +/- 5.4 g (p less than 0.0001). Another study showed an estimate of the mean cellular glucose uptake (MCUg) per minute and per kilogram body weight. The MCUg following glucose loading decreased considerably in hypertensives with pathological Kg values. The percentage reduction ranged between 50 and 55% hypertensives with pathological Kg values 4.1 +/- 0.8, and normotensives with normal Kg values, 8.0 +/- 0.6 (p less than 0.0001).(ABSTRACT TRUNCATED AT 400 WORDS)

A behavioral treatment program as a therapy in the control of primary hypertension.

In order to assess the effects of a Behavioral Treatment Program in the control of primary hypertension, twenty one unmedicated hypertensives were randomly allocated to three groups: first, a treatment group (BHG) receiving a Behavioral Treatment which included: deep muscle relaxation, peripheral temperature Biofeedback and anxiety management training; second, the placebo attention control group (PHG) and third, a control group of hypertensives too (CHG). Additionally, were compared with seven normotensives subjects (CNG). The post-treatment measures showed a significant reduction (p < 0.001) in systolic and diastolic values only in the (BHG). In a six months follow-up the (BHG) group still showed a significant reduction in the systolic and diastolic BP (p < 0.02; p < 0.01). Moreover individual variations in response to treatment were observed in this group, (BHG).

Acute hypotensive action of clonidine after intravenous infusion in hypertensive emergencies.

Clonidine was administered by intravenous infusion to 12 patients classified as having exaggerated arterial hypertension, their systolic (SAP), diastolic (DAP) and mean (MAP) arterial pressures were significantly reduced from the third min. The maximal percentage reduction (Mean +/- SEM) reached 30.1 +/- 3.1% (SAP) and 24.7 +/- 2.9% (DAP) after 30 to 110 min of infusion. Initially there were transitory initial increases in SAP (3 patients) and DAP (1 patient). The increases in blood pressure were related to low body surface area (BSA). The dose of clonidine per m2BSA able to reduce by 10% either SAP or DAP (active dose-10), and the dose able to reduce SAP or DAP by 10 mmHg in one minute (systolic or diastolic clonidine unit) were calculated, providing indices for detecting clonidine responsiveness in patients with exaggerated hypertension. This method is advantageous when using clonidine intravenously because it diminishes the risk of overdosage.

Echocardiographic assessment of doxazosin on left ventricular mass in patients with essential hypertension.

A single daily dose of doxazosin taken during a 12-week period produced a significant reduction in blood pressure and left ventricular mass index in patients with mild or moderate hypertension. The systolic shortening coefficient was also increased and a trend in the improvement of ejection fraction, rate of circumferential fiber shortening, systolic contraction time, and preejective/ejective ratio was observed. No change in heart rate was recorded and no patients had side effects. The serum lipid profile was modified favorably, particularly with regard to the low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio. By producing a reduction in blood pressure and left ventricular mass while favorably modifying the serum lipid profile, doxazosin produced a beneficial change in the overall coronary heart disease risk profile.

Fiebre prolongada: una visión contemporánea de un viejo problema clínico de difícil diagnóstico / Prolongue fever: a contemporary vision and old clinical problem to diagnosis difficult

El objetivo de este estudio es determinar las causas más frecuentes de Síndrome Febril Prolongado (SFP) en el HUC y diseñar estrategias de aproximación diagnóstica al paciente con SFP en nuestro medio. Se presenta un estudio prospectivo realizado en los servicios Medicina Interna y Enfermedades Infecciosas del Adulto de HUC, entre diciembre de 1993 y diciembre de 1995, obteniéndose 100 pacientes que cumplieron los siguientes criterios de inclusión: 1) Edad> 12 años; 2) Fiebre >38,3ºC y 3) Fiebre >21-días de duración. Se llenó un formato de extracción de datos que incluyó: 1) identificación, 2) antecedentes epidemiológicos, 3) síntomas constitucionales, 4) examen físico, 5) estudios complementarios (laboratorio, imagenología y citomorfológicos). Los resultados se analizaron según métodos estadísticos descriptivos. De los pacientes, 58 correspodieron al sexo masculino y 42 al sexo femenino. La edad promedio fue de 36.9 años con rango entre 13 y 80, procedentes en su mayoría de Caracas (51 por ciento) y Estado Miranda (22 por ciento). Las patologías se presentaron en el siguiente orden: Infecciosas 55 por ciento, neoplásicas 18 por ciento, enfermedades del tejido conectivo 14 por ciento, misceláneas 6 por ciento, sin diagnóstico 7 por ciento. El S.I.D.A. se presenta como la patología más frecuente (24 por ciento) lo que implica un cambio en el abordaje del paciente con SFP, siendo prioritario determinar la presencia del Virus de Inmunodeficiencia Humana (HIV), para clasificar a los pacientes en seronegativos que serán estudiados según esquemas clásicos, y seropositivos donde deberán buscarse principalmente causas infecciosas. En ambos grupos deberán investigarse las patologías infecciosas propias de nuestro medio