Effects of resistance training using known vs unknown loads on eccentric-phase adaptations and concentric velocity.

The aims of this study were to compare both eccentric- and concentric-phase adaptations in highly trained handball players to 4 weeks of twice-weekly rebound bench press throw training with varying loads (30%, 50% and 70% of one-repetition maximum [1-RM]) using either known (KL) or unknown (UL) loads and to examine the relationship between changes in eccentric- and concentric-phase performance. Twenty-eight junior team handball players were divided into two experimental groups (KL or UL) and a control group. KL subjects were told the load prior each repetition, while UL were blinded. For each repetition, the load was dropped and then a rebound bench press at maximum velocity was immediately performed. Both concentric and eccentric velocity as well as eccentric kinetic energy and musculo-articular stiffness prior to the eccentric-concentric transition were measured. Results showed similar increases in both eccentric velocity and kinetic energy under the 30% 1-RM but greater improvements under 50% and 70% 1-RM loads for UL than KL. UL increased stiffness under all loads (with greater magnitude of changes). KL improved concentric velocity only under the 30% 1-RM load while UL also improved under 50% and 70% 1-RM loads. Improvements in concentric movement velocity were moderately explained by changes in eccentric velocity (R2 =.23-.62). Thus, UL led to greater improvements in concentric velocity, and the improvement is potentially explained by increases in the speed (as well as stiffness and kinetic energy) of the eccentric phase. Unknown load training appears to have significant practical use for the improvement of multijoint stretch-shortening cycle movements.

The effects of training with loads that maximise power output and individualised repetitions vs. traditional power training.

BACKGROUND: It has been suggested that strength training effects (i.e. neural or structural) vary, depending on the total repetitions performed and velocity loss in each training set. PURPOSE: The aim of this study is to compare the effects of two training programmes (i.e. one with loads that maximise power output and individualised repetitions, and the other following traditional power training). METHODS: Twenty-five males were divided into three groups (optimum power [OP = 10], traditional training [TT = 9] and control group [CG = 6]). The training load used for OP was individualised using loads that maximised power output (41.7% ± 5.8 of one repetition maximum [1RM]) and repetitions at maximum power (4 to 9 repetitions, or 'reps'). Volume (sets x repetitions) was the same for both experimental groups, while intensity for TT was that needed to perform only 50% of the maximum number of possible repetitions (i.e. 61.1%-66.6% of 1RM). The training programme ran over 11 weeks (2 sessions per week; 4-5 sets per session; 3-minute rests between sets), with pre-, intermediate and post-tests which included: anthropometry, 1RM, peak power output (PPO) with 30%, 40% and 50% of 1RM in the bench press throw, and salivary testosterone (ST) and cortisol (SC) concentrations. Rate of perceived exertion (RPE) and power output were recorded in all sessions. RESULTS: Following the intermediate test, PPO was increased in the OP group for each load (10.9%-13.2%). Following the post-test, both experimental groups had increased 1RM (11.8%-13.8%) and PPO for each load (14.1%-19.6%). Significant decreases in PPO were found for the TT group during all sets (4.9%-15.4%), along with significantly higher RPE (37%). CONCLUSION: OP appears to be a more efficient method of training, with less neuromuscular fatigue and lower RPE.

Active tuberculosis patients have high levels of IgA anti-alpha-crystallin and isocitrate lyase proteins.

SETTING: Mexico City, Mexico. OBJECTIVE: To identify proteins synthetised by Mycobacterium tuberculosis in hypoxic culture, which resemble more closely a granuloma environment than aerobic culture, and to determine if they are recognised by antibodies from patients with active pulmonary tuberculosis (PTB). DESIGN: Soluble extracts from M. tuberculosis H37Rv cultured under aerobic or hypoxic conditions were analysed using two-dimensional polyacrylamide gel electrophoresis, and proteins over-expressed under hypoxia were identified by mass spectrometry. The presence of immunoglobulin (Ig) G, IgA and IgM antibodies against these proteins was determined in the serum of 42 patients with active PTB and 42 healthy controls. RESULTS: We selected three M. tuberculosis H37Rv proteins (alpha-crystallin protein [Acr, Rv2031c], universal stress protein Rv2623 and isocitrate lyase [ICL, RV0467]) that were over-expressed under hypoxia. Titres of anti-Acr and anti-ICL IgA antibodies were higher in patients than in healthy controls, with an area under the receiver operating characteristic curve of 0.71 for anti-ICL IgA antibodies. CONCLUSION: ICL could be used in combination with other M. tuberculosis antigens to improve the sensitivity and specificity of current serological TB diagnostic methods.

Load knowledge reduces rapid force production and muscle activation during maximal-effort concentric lifts.

PURPOSE: Rapid force development is a key factor influencing performance and injury risk in movements where little time is available for force production; thus there is a need to develop interventions that enhance this ability. In the present study, the influence of load knowledge on mechanical output [rate of force development; (RFD) and power] and muscle activation [electromyographic (EMG) responses] in the concentric-only bench press throw exercise was studied. METHODS: Fifteen strength-trained individuals performed 6 sets of 6 maximal explosive repetitions in a single test session after extensive familiarization. In three of these sets the subjects were given knowledge about the load before each repetition (known condition; KC), whereas in the other three sets they were given no information (unknown condition; UC). In both conditions the loads were 30, 50 and 70 % of maximum, but condition and load orders were randomized. RESULTS: RFD (24-50 %) and power output (20-39 %) were significantly higher in UC in the early time intervals from movement onset (<150 ms). In addition, UC elicited greater EMG amplitudes in anterior deltoid both prior to movement onset (pre50-0 ms) and in the early time intervals (<100 ms) after movement onset, and in pectoralis major after movement onset (<100 ms). CONCLUSIONS: UC resulted in a greater initial activation of the muscles and both a higher RFD and mechanical power output in the early phase of the movement under all loading conditions (30-70 % of maximum). UC appears to offer a novel neuromuscular stimulus, and further research on the effects of continued exposure is warranted.

Simultaneous treatment effects in learning four tennis shots in contextual interference conditions.

This study investigated simultaneous treatments in contextual interference (blocked and random practice) and their effect on the process of learning four tennis shots. 8 tennis players participated in the research, which was carried out in two phases. The first phase involved a 3-wk. period of 12 sessions with 192 practice tennis shots per session for each tennis player. The second phase comprised 4 retention tests carried out at 48 hr. and 2, 4, and 6 weeks following the learning phase. This phase consisted of evaluating the retention of the skills that had been practiced during the learning phase. The results indicated an improvement in the quality of shots for both practice conditions during the learning phase. Differences in retention appeared relative to differences in the type of practice conditions (random or blocked) in which the skill was learned and also depended on the type of shot and the time that had elapsed since the learning period.

Evaluation of the polymerase chain reaction in the diagnosis of miliary tuberculosis in bone marrow smear.

OBJECTIVE: Miliary tuberculosis (MTB) is difficult to diagnose. When prompt diagnosis is necessary, the polymerase chain reaction (PCR) to detect mycobacterial DNA may be valuable. SETTING: Tuberculosis clinic in an academic tertiary-level hospital in Mexico. DESIGN: Bone marrow (BM) aspiration samples from 30 consecutive clinically suspected MTB patients and 58 non-tuberculosis hematologic patients were evaluated by in-house PCR using a fragment of the insertion sequence IS6110; results were compared with those obtained by acid-fast-stained smears, culture in Löwenstein-Jensen medium, histology, and serology. RESULTS: Tuberculosis diagnosis was confirmed in all MTB suspects, 28 by microscopy and culture in pulmonary or extra-pulmonary samples other than BM, and two by clinical and radiologic improvement after antituberculosis treatment. In fresh BM specimens, in-house PCR was positive in 21/30 (70%) suspects, contrasting with only one positive (3.3%) in staining and culture, and four with compatible histologic findings (13.3%). BM samples from the control group showed negative results in bacteriologic and histologic studies, except in nine who had positive PCR results. These nine control cases had malignant processes. CONCLUSION: PCR in aspirates of BM is a useful diagnostic assay in cases of MTB, mainly when bacteriological results are negative.

Tuberculosis is still a major cause of cervical lymphadenopathies in adults from developing countries.

To establish the frequency of infectious aetiology in Mexican adult patients with cervical lymphadenopathies (CLAs), 87 consecutive patients with enlarged cervical lymphatic nodes, HIV negative and without anti-tuberculous treatment, were selected from a tertiary-level speciality concentration hospital. Histopathological studies, investigation of acid-fast bacilli, cultures in Löwenstein Jensen and Mycobacterium growth indicator tube (MGIT) media, and in-house polymerase chain reaction (PCR) with IS6110-based primers for Mycobacterium tuberculosis complex were performed in resected lymphatic nodes. Non-infectious aetiology corresponded to 45 cases (52 %). Tuberculosis was suspected in 42 cases (48%) by histology and confirmed positive results were obtained by staining in 8 (19%), by culture in 23 (55%), and by PCR in 34 (81 %) patients. All were confirmed after therapeutic success. In addition to the epidemiological transition process occurring in Mexico, tuberculosis remains an important cause of CLA. Histopathology with confirmatory studies including PCR can detect tuberculous aetiology.

[Usefulness of the coccidioidin skin test in patients with type diabetes mellitus in an endemic zone]. / Utilidad de la prueba cutánea a la coccidioidina en personas con diabetes mellitus tipo 2 en una zona endémica.

OBJECTIVE: There are few studies available about skin response to mycotic antigens in diabetes mellitus subjects, therefore, the possible difference of skin reactivity to coccidioidin in subjects with and without diabetes mellitus was analyzed. MATERIAL AND METHODS: The prevalence of skin reactivity to coccidioidin in a population sample of 1651 subjects in a coccidioidomycosis endemic zone was estimated using a transversal design. Subjects with diabetes mellitus were identified and the diagnosis was validated by clinical and laboratory criteria. In order to determine the reactivity association level with the diabetes mellitus history, data was compared with the population sample, through logistic regression analysis adjusted by age, sex and residence geographical area. Odds ratio (OR) and 95% confidence intervals were obtained. RESULTS: In the population study, there were 665 coccidioidin positive subjects (40.28% rate). Seventy six cases with diabetes mellitus were identified, 23 were positive to the test (30.26% rate) with an odds ratio of 0.63 for this group (95% CI 0.37-1.07). The OR decrease to 0.52 (95% CI 0.31-0.88, p = 0.014) with the adjusted logistic regression analysis. CONCLUSION: Coccidioidin reactivity was lower in the diabetes mellitus cases than in general population. It is necessary to be cautious with the coccidioidin test interpretation in people with DM 2.

La hemodinamia cardiopulmonar en el paciente neumópata crónico. Un comentario clínico / Cardiopulmonary haemodynamic in chronic neumologic patients. A clinical comment

Las enfermedades pulmonares crónicas son una causa frecuente de hipertensión pulmonar y cor pulmonale crónico, su existencia implica una menor supervivencia y por lo tanto mal pronóstico. Esta revisión analiza los probables factores fisiopatológicos que participan en la génesis de la hipertensión pulmonar de nuestros tres primeros grupos de trabajo (enfermedad pulmonar obstructiva crónica, neumopatía intersticial y apnea obstructiva del sueño). En general, la hipertensión pulmonar de este grupo de pacientes es el resultado de uno o varios factores: factores vasoactivos (hipoxia, acidosis, etcétera), factores pasivos (hiperflujo, hipertensión venocapilar y daño vascular); este último factor a su vez puede ser mediado por la patología de base (fibrosis, inflamación, obstrucción, etcétera) o bien ser secundario a remodelación de la circulación pulmonar por hipoxia crónica e hiperflujo. Otros factores de origen funcional descritos han sido la disminución del volumen pulmonar propia de las patologías intersticiales; así como el aumento en la resistencia de la vía aérea y la eritrocitosis secundaria, hallazgos que caracterizan a la enfermedad pulmonar obstructiva crónica. El adecuado conocimiento en la fisiopatología de estas enfermedades, así como la magnitud de la hipertensión pulmonar requiere del estudio de la circulación pulmonar a través del cateterismo cardiaco derecho por lo que se justifica la existencia de un servicio de hemodinamia en todo hospital dedicado a la enseñanza de la neumología.

Efficacy, tolerance, and pharmacokinetics of the combination of stavudine, nevirapine, nelfinavir, and saquinavir as salvage regimen after ritonavir or indinavir failure.

The high rate of protease inhibitor treatment failure in clinical cohorts makes it necessary to define novel salvage therapies. In a prospective study of 31 HIV-infected patients included in a salvage regimen with stavudine, nevirapine, nelfinavir, and saquinavir, viral load decreased a median of 1.65 log(10) and 1.95 log(10) after 6 and 12 months of treatment, respectively, and 35 and 56% of patients had an HIV RNA level below 50 copies/ml at the same time points. At baseline, the mean number of mutations in the protease gene was 10 (2-19), and the V82A and L90M mutations were present in 54 and 21% of patients. The presence of the V82A mutation did not affect significantly the rate of response (36 vs. 38%), whereas the L90M mutation was associated with treatment failure (0 vs. 43%). Plasma trough levels of nelfinavir (NFV) and saquinavir (SQV), in a twice daily dosing regimen, were above the protein-corrected IC(95) in most patients despite the addition of an enzymatic inducer such as nevirapine, and peak levels were 2- and 5-fold increased with respect to standard doses. However, pharmacokinetics of saquinavir-hard gel capsule (SQV-hgc) did not improve significantly in the three times daily dosing regimen. In conclusion, the combination of stavudine, nevirapine, nelfinavir, and saquinavir increased plasma drug levels and produced an adequate virological response in patients who had failed indinavir or ritonavir therapy. This degree of response is not significantly decreased in the presence of genotypic mutations associated with indinavir/ritonavir (IDV/RTV) resistance.

[Who smoke at a general hospital? Clinical comment]. / Quiénes fuman en un hospital general? Comentario clínico.

BACKGROUND AND OBJECTIVE: Tobacco consumption is a public health problem. Hospitals are not free of this circumstance because there are smokers inside these institutions; thus, it is important to identify who smoke in hospitals. METHOD AND RESULTS: A general survey with closed questions was carried out among 659 workers at a tertiary level general hospital. Smoking habit was positive in 184 employees and negative in 475. The majority of smokers were married and worked in the administrative offices, 46 of which belong to the medical area. Academic level was not an important determinant for tobacco consumption. The habit began between 10 to 20 years of age, mainly in relation with a sensation of pleasure, relaxation, and the need to smoke. CONCLUSIONS: The main site for smoking was the working area, 70% of nonsmokers are converted passive non-voluntary smokers. It is important to take actions to avoid tobacco smoking in hospitals in pursuit of a hospital environment free of tobacco smoke.

A clinical study of the combination of 100 mg ritonavir plus 800 mg indinavir as salvage therapy: influence of increased plasma drug levels in the rate of response.

PURPOSE: The purpose of our study was to evaluate the efficacy of indinavir (IDV) in a twice daily dosing regimen with coadministration of 100 mg ritonavir (RTV) and to explore the influence of plasma drug levels in the rate of virologic response. METHOD: We performed a prospective study of 59 patients who switched to a salvage regimen with two nucleoside analogs plus the combination of 100 mg RTV plus 800 mg IDV twice daily. Pharmacokinetics of IDV and RTV were assessed in 11 patients. RESULTS: Previous antiretroviral exposure was 44 months, and 78% and 39% of patients had previously failed regimens with either IDV or RTV. Median CD4 count was 248 x 10(6)/L and HIV load was 3.9 log(10) copies/mL. The median number of mutations in the protease gene was 9 (3-14), predominantly at residues 82 (53%), 90 (42%), and 46 (32%). After 24 weeks, 61% of patients had a viral load decrease greater than 1 log(10), and 38% had a viral load below 50 copies/mL. Nephrolitiasis, hematuria, or flank pain was observed in 13 patients (22%), leading to withdrawal in six cases (10%). IDV trough levels were well above the IC(95) (median 1.75 mg/L, interquartile range 1.07-2.57), but RTV trough levels were below the IC(95) in 88% of patients. There was a close correlation between higher peak levels of IDV, virological response, and renal toxicity. CONCLUSION: RTV/IDV 100/800 mg in a twice daily dosing regimen is associated with a significant virological response in patients with antiretroviral treatment failure. The correlation between plasma drug levels, toxicity, and response suggests the usefulness of individualized drug monitoring.

Percentage of adherence correlates with the risk of protease inhibitor (PI) treatment failure in HIV-infected patients.

OBJECTIVES: To determine the effect of adherence on the rate of protease inhibitor (PI) treatment failure among human immunodeficiency virus (HIV)-infected patients. METHODS: A prospective study of a cohort of 282 patients who initiated PI therapy from March 1996 to December 1997. Adherence was quantified as the percentage of prescribed doses reportedly taken and treatment failure was defined as HIV RNA levels above 200 copies/ml after 1 year on therapy. RESULTS: Overall, 190 patients (67%) missed prescribed doses. However, mean percentage of doses taken was 91% (range, 21-100%). Demographic, virological and immunological characteristics could not predict adherence outcomes. The causes of non-adherence included intolerance or side effects (35%), complexity of treatment (23%), or recurrence in active drug abuse (17%), whereas abandonment owing to HIV-related disease was uncommon (6%). A degree of adherence above 90% correlated significantly with viral suppression [relative risk (RR) 1.69; 95% confidence interval (CI) 1.1-2.56; P<0.01]. In a multivariate analysis, a lower degree of adherence (RR, 0.96; P=0.006), a higher HIV viral load (RR, 2.03; P=0.0001), prior antiretroviral therapy (RR, 2.5; P=0.01), and use of saquinavir-hard gel capsules (saquinavir-HGC) (RR, 1.77; P=0.03) were strongly associated with treatment failure. CONCLUSION: The percentage of adherence and initial HIV viral load are the most important determinants of virological response to PI therapy and non-adherence is related to treatment-related factors in the majority of cases.

Predictors of long-term response to protease inhibitor therapy in a cohort of HIV-infected patients.

OBJECTIVE: To assess the rate of long-term effectiveness and factors associated with response to protease inhibitor therapy in a cohort of HIV-infected patients. DESIGN AND SETTING: Prospective, non-randomized study in a tertiary care centre. PATIENTS: A total of 400 HIV-infected patients who started on protease inhibitor therapy (saquinavir, 28%; ritonavir, 26%; indinavir, 46%) from March 1996 to March 1997. MAIN OUTCOMES MEASURES: Long-term virological and immunological effectiveness were defined as HIV RNA levels below 200 copies/ml and CD4+ cell count increase greater than 100 x 10(6)/l, respectively, after 12 months of therapy. RESULTS: Fifty-seven per cent of patients had a prior AIDS-defining illness, and 91% had received nucleoside analogues for a median time of 28 months. Median CD4+ count was 86 x 10(6) cells/l and HIV RNA level was 4.46 log10 copies/ml. The global rate of virological and immunological effectiveness at 1 year was 45 and 59%, respectively. In a logistic regression analysis, treatment failure was associated with higher baseline HIV load [relative risk (RR), 2.10; P<0.01], prior antiretroviral therapy (RR, 2.07; P<0.01), and use of saquinavir (RR, 1.55; P = 0.03), whereas a reduction of more than 1 log10 in HIV load within the first 3 months on therapy was strongly associated with response (RR, 0.65; P<0.01). There was no strict correlation between virological and immunological effectiveness (r = -0.35; P = 0.01). CONCLUSIONS: Nearly half of the patients maintain undetectable HIV load after 1 year of therapy, although important immunological benefit can be obtained in a greater proportion of patients. These data suggest the use of the most potent antiretroviral therapy in pretreated patients with high HIV load, and the capacity of initial virological decline to predict the long-term outcome.

[Surgical treatment of invasive thymoma with superior vena cava syndrome. 3 case reports]. / Tratamiento quirúrgico del timoma invasor con síndrome de vena cava superior. Informe de tres casos.

Three patients with invasive thymoma and superior vena cava syndrome with severe symptoms of cerebral venous hypertension and respiratory obstruction are presented. Two patients showed a type I obstruction and the other had a type II obstruction as defined by Stanford and Doty. In all of them, the tumor was resected and a graft bypass was placed between the left innominate vein and the right appendage. In two patients the grafts were venous and in the other it was a PTFE. All grafts were reinforced with wire rings. The patients improved and the symptoms of the SVCS disappeared, the average time of permeability was 10 months.

Burden of Mycobacterium tuberculosis in sputum samples can be reliably determined using a quantitative, non-radioactive polymerase chain reaction assay.

OBJECTIVE: To develop a rapid assay for quantitation of Mycobacterium tuberculosis in sputum samples using the competitive polymerase chain reaction (PCR) and a colorimetric microtiter well detection format. DESIGN: The assay relies on the co-amplification of a 419 base pair (bp) pab fragment of M. tuberculosis together with a target template (pab/tet) made by splicing a fragment of tet excised from pbr322 between the 5' and 3' ends of the pab fragment to create a 380 bp hybrid template amplified with the same primers but readily distinguishable using probes specific for either pab or tet. RESULTS: We demonstrate a good correlation between the results obtained using this assay and the results of quantitative culture. CONCLUSION: This assay provides quantitative information regarding M. tuberculosis burden in samples containing between 10(3) and 10(8) colony forming units/milliliter (CFU/ml).

Oximetría de pulso y broncoscopia / Pulse oximetry and bronchoscopy

La oximetría de pulso es un método no invasivo y barato para vigilar de manera continua la oxigenación arterial en tiempo real. La oximetría de pulso empleada de rutina durante la realización de broncoscopias, permite apreciar la oxigenación durante este procedimiento. La saturación del oxígeno se mantiene por arriba de 80 por ciento, en pacientes con neumopatía crónica, con la administración de oxígeno por puntas nasales a flujos de 3 litros por minuto, lo que permite realizar el procedimiento con seguridad

[Levels of carboxyhemoglobin in smokers and non-smokers from 2 cities of the Mexican high plateaux]. / Niveles de carboxihemoglobina en sujetos no fumadores y fumadores de dos ciudades del altiplano mexicano.

Carboxyhemoglobin levels (COHb) were determined in residents of two Mexican cities (Mexico City and Toluca) at altitudes of 2200 and 2600 meters above sea level. The figures in non-smokers of both cities were slightly higher than those seen at sea level by others: 1.63% in Mexico City and 1.54% in Toluca versus 0.5-1% at sea level. There were no intercity differences in smokers and non-smokers, but there were intergroup differences in both cities (p less than 0.01 in Mexico City, and p less than 0.05 in Toluca). Our findings suggest that the most important source of carbon monoxide in smokers is tobacco smoking, and that the COHb level may be reliable index to establish active smoking.