Differential regulation of steroid 5alpha-reductase isozymes expression by androgens in the adult rat brain

The enzyme 5alpha-reductase (5alpha-R) is present in many mammalian tissues, including the brain. The physiological importance of 5alpha-R in the brain derives from its capability to convert testosterone (T) to a more potent androgen, dihydrotestosterone (DHT), and to convert progesterone and deoxycorticosterone (DOC) to their respective 5alpha-reduced derivatives, precursors of allopregnanolone and tetrahydroDOC, potent allosteric modulators of the gamma-aminobutyric acid receptor (GABA(A)-R). 5alpha-R occurs as two isoforms, 5alpha-R type 1 (5alpha-R1) and 5alpha-R type 2 (5alpha-R2). We studied the effects of T and DHT on the mRNA levels of both 5alpha-R isozymes in the prefrontal cortex of the adult rat, using an accurate and precise method that combines the high specificity of one-step quantitative RT-PCR with the sensitivity of capillary electrophoresis. Our results demonstrate that both isozymes of 5alpha-R are expressed in the cerebral cortex of adult rats. The gene expression of 5alpha-R type 2 is under the positive control of T and DHT. The gene that codes for 5alpha-R type 1 is not constitutive, because its expression is negatively regulated by T and DHT. These results open up a new research line that may lead to a better understanding of the role of 5alpha-R isozymes in the physiology of the central nervous system.

DHEA, PREG and their sulphate derivatives on plasma and brain after CRH and ACTH administration

The term neurosteroids applies to steroids that are synthesized in the nervous system, either de novo from cholesterol or from steroid hormone precursors. RIA was used to determine plasma and brain levels of the neurosteroids pregnenolone (PREG), dehydroepiandrosterone (DHEA), and their sulfate derivatives (PREG-S and DHEA-S) in male and female rats after administration of two typical stress hormones: corticotropin-releasing hormone (CRH) and adrenocorticotropin hormone (ACTH). In all cases, the parameters measured were detectable in plasma and brain. PREG, PREG-S, and DHEA increased significantly in plasma and brain after CRH and ACTH administration in males and females. Because neurosteroids play an important role in mammalian physiology, including that of humans, stress situations may alter the physiological functions regulated by these neurosteroids.

Alcohol intoxication increases allopregnanolone levels in female adolescent humans

Teenage drinking is a cause of growing concern in industrialized countries, where almost 35% of alcohol drinkers are under 16 years old. Increased anxiety, irritability, and depression among adolescents may induce them to seek the anxiolytic and rewarding properties of alcohol. We studied the effects of acute alcohol intoxication (AAI) on the plasma levels of progesterone and allopregnanolone in female adolescents. Blood samples were drawn from female adolescents who arrived at the emergency department. One study group was formed by those who arrived with evident behavioral symptoms of AAI and the other by those arriving for mild trauma (contusions, sprains) after no consumption of alcohol (controls). Our results demonstrate that AAI significantly increases serum progesterone and allopregnanolone levels in both follicular and luteal phases of the ovarian cycle. Since alcohol and allopregnanolone positively modulate gamma-aminobutyric acid type A (GABA(A)) receptors, allopregnanolone may play a major role in the anxiolytic and rewarding effects of alcohol, either directly or by influencing the sensitivity of GABA(A)-receptors to alcohol.

Early detection of PrPres in BSE-infected bovine PrP transgenic mice

Transgenic mouse lines expressing different levels of the bovine prion protein gene (boPrP(C)) were generated. Upon infection with BSE prions, all transgenic lines tested exhibited characteristics of the bovine disease. Typical CNS spongiform degeneration was observed by histopathology and presence of PrP(res) could be detected both by Western blot and immunohistochemistry (IHC) assays, confirming for this model the absence of an interspecies barrier to BSE infection. Differences in incubation times post-inoculation depend upon the expression level of boPrP(C) and the amount of prions in the inoculum. In the absence of clinical signs, pathognomonic markers of disease could be detected as early as 150 or 196 days post-inoculation by IHC and Western blot analysis, respectively. This result indicates that prion infectivity in experimental mouse bioassays can be measured earlier by assessing immunologically the presence of PrP(res) in brains from inoculated animals. Although these transgenic mice were also susceptible to sheep scrapie prion infection, the extent of incubation times was considerably longer and PrP(res) was detected in only 70 % of inoculated mice. Interestingly, transgenic mice-propagated sheep scrapie prions displayed distinct biochemical properties when compared to both the original sheep scrapie and transgenic mouse-propagated BSE inoculum.

The Antimicrobial Properties of Different Strains of Lactobacillus spp. Isolated from Kefir

The characteristics of 58 strains of Lactobacillus spp. isolated from kefir were studied. These strains were tested for adherence to human enterocyte-like Caco-2 cells, resistance to acidic pH and bile acid, antimicrobial activities against enteropathogenic bacteria and inhibition of Salmonella typhimurium attachment to Caco-2 cells. The best probiotic properties were observed in L. acidophilus CYC 10051 and L. kefiranofaciens CYC 10058. L. kefiranofaciens CYC 10058 produced an exopolysaccharide, which revealed that it was closely related to kefiran, a polysaccharide with antitumoral properties. This is the first in vitro study about the antimicrobial characteristics of the Lactobacillus population of kefir.

Magnetic relaxation of interacting co clusters: crossover from two- to three-dimensional lattices

The influence that dipole-dipole interactions exert on the dynamics of the magnetization of nanometer-sized Co clusters has been studied by means of ac and dc susceptibility experiments. These clusters grow in a quasiordered layered structure, where all relevant parameters can be tailored and measured independently. Our data show without ambiguity that the magnetic relaxation becomes slower as the degree of interaction increases. The effective activation energy increases linearly with the number of nearest neighbor clusters, evolving from the value for a 2D layer to the fully 3D behavior, which is nearly reached for five layers. The experimental results agree quantitatively with the predictions of a simple model.

ALS and PDC of Guam: forty-year follow-up

BACKGROUND

It was noticed in the mid-1950s that the incidence of ALS and parkinsonism--dementia complex (PDC) were much higher on Guam than anywhere else in the world. In 1958, a registry of patients and controls was established to ascertain the familial and genetic aspects of these diseases. Patients and individually matched controls and their relatives were registered from 1958 to 1963. The registry was updated and analyzed in 1998 through 1999.

OBJECTIVE

To ascertain whether first-degree relatives of patients had a higher risk for developing ALS or PDC than relatives of controls.

METHODS

During the period of 1958 to 1963, 126 new patients and 126 individually matched controls and their respective first-degree relatives and spouses were evaluated neurologically and registered. Forty years later, the number of new cases among the patient and control relatives were compared to an expected number of new cases based on the age- and sex-specific incidence of ALS and PDC in the population at large.

RESULTS

From 1958 to 1999, there were 102 new ALS or PDC cases among relatives of patients and 33 among relatives of controls. These values were compared with the derived expected values. There were more observed than expected new cases among patients' relatives, and less observed cases than expected among the controls' relatives.

CONCLUSIONS

Relatives of patients with ALS or PDC have significantly higher risks for developing the disease than the Guamanian population, whereas relatives of controls have significantly lower risks.

Effects of acute alcohol intoxication on pituitary-gonadal axis hormones, pituitary-adrenal axis hormones, beta-endorphin and prolactin in human adults of both sexes

- The effects of acute alcohol intoxication (AAI) on the pituitary-gonadal axis hormones, and the possible contribution of pituitary-adrenal axis hormones, beta-endorphin and prolactin to alcohol-induced dysfunction of pituitary-gonadal axis hormones were studied in adult men and women. Blood samples were drawn from adults of both sexes who arrived at the emergency department with evident behavioural symptoms of drunkenness (AAI) or from adult volunteers with nil consumption of alcohol (controls). Our results demonstrated that AAI produces a high increase in plasma prolactin, corticotropin (adrenocorticotropic hormone, ACTH), and cortisol in adults of both sexes, a decrease in luteinizing hormone levels only in men, an increase in dehydroepiandrosterone-sulphate (DHEAS) and a contradictory behaviour of testosterone according to gender, with increased plasma testosterone in women and a decrease in men. ACTH and prolactin correlated positively with cortisol, DHEAS and testosterone in women, which suggests that prolactin and ACTH could contribute to stimulated adrenal androgen production. In contrast, the decrease in testosterone and increase in beta-endorphin in men suggests that AAI could have an inhibitory effect on testicular testosterone, perhaps mediated by beta-endorphin. Our results suggest that the effect of alcohol on pituitary-gonadal axis hormones in humans could depend on the gender and degree of sexual maturity of the individual.

A rapid method for 90Sr determination in the presence of 137Cs in environmental samples

A rapid method for the determination of 90Sr in the presence of 137Cs using the Cherenkov radiation technique is described. The contribution of 137Cs to gross Cherenkov radiation (90Y + 137Cs) was examined for 137Cs /90Sr ratios ranging from 0.09 to 2.50 for 137Cs activities ranging from 2 to 1,211 Bq. Results from direct Cherenkov radiation measurement and results after radiochemical separation of 90Y from 90Sr for samples containing both 90Sr and 137Cs were compared. Errors below 5% were obtained for 137Cs /90Sr ratios lower than 1, when no separation was performed, independently of the activity level. However, errors between 10% and 35% were obtained for 137Cs/90Sr ratios higher than 1. In order to determine 90Sr activity in the presence of 137Cs using the Cherenkov technique, a multiple linear regression analysis model was established to correct the data for 137Cs content. The mathematical correction proposed was validated using 66 artificially contaminated lettuce samples in a laboratory experiment by taking into account the activity levels of 137Cs and 90Sr and the radionuclide ratios. Comparison of mathematically corrected radionuclide ratios with the results obtained without correction shows that, for radionuclide ratios higher than 1, error values for measuring 90Sr activity using the mathematical model were much smaller than when no radiochemical separation was performed. On the other hand, for ratios lower than 1, error values when measuring 90Sr activity with radiochemical separation were smaller than when mathematical correction was performed. In spite of this, the mathematical correction is an appropriate way of reducing the time needed to determine radiostrontium using the Cherenkov radiation technique. The method proposed could be a powerful tool for environmental research whenever the contents of 90Sr and 137Cs have to be determined.

First field trial of a transmissible recombinant vaccine against myxomatosis and rabbit hemorrhagic disease

As a novel approach for immunisation of wild rabbits, we have recently developed a transmissible vaccine against myxomatosis and rabbit hemorrhagic disease (RHD) based on a recombinant myxoma virus (MV) expressing the RHDV capsid protein [J. Virol. 74 (2000) 1114]. The efficacy and safety of the vaccine have been extensively evaluated under laboratory conditions. In this study, we report the first limited field trial of the candidate vaccine that was undertaken in an island of 34 Has containing a population of around 300 rabbits. Following administration by the subcutaneous route to 76 rabbits, the vaccine induced specific antibody responses against both myxomatosis and RHDV in all the inoculated rabbits. Furthermore, the recombinant virus exhibited a limited horizontal transmission capacity, promoting seroconversion of around 50% of the uninoculated rabbit population. No evidence of undesirable effects due to the recombinant virus field release was detected.

High prevalence of low HDL cholesterol concentrations and mixed hyperlipidemia in a Mexican nationwide survey

The prevalence of lipid abnormalities revealed in a survey done in 417 Mexican cities is described. Information was obtained on 15,607 subjects, aged 20 to 69 years. In this report, only samples obtained after a 9- to 12-h fast were included (2,256 cases: 953 men and 1,303 women). The population is representative of Mexican urban adults. Mean lipid concentrations were: cholesterol, 4.80 mmol/l; triglycerides, 2.39 mmol/l; HDL cholesterol, 1.00 mmol/l; and LDL cholesterol, 3.06 mmol/l. The most prevalent abnormality was HDL cholesterol below 0.9 mmol/l (46.2% for men and 28.7% for women). Hypertriglyceridemia (>2.26 mmol/l) was the second most prevalent abnormality (24.3%). Severe hypertriglyceridemia (>11.2 mmol/l) was observed in 0.42% of the population. Increased LDL cholesterol (> or =4.21 mmol/l) was observed in 11.2% of the sample. Half of the hypertriglyceridemic subjects had a mixed dyslipidemia or low HDL cholesterol. More than 50% of the low HDL cholesterol cases were not related to hypertriglyceridemia. Insulin resistance was found in 59% of them. In conclusion, the prevalence of hypoalphalipoproteinemia and other forms of dyslipidemia in Mexican adults is very high and it is among the highest previously reported worldwide.

Effects of CRH and ACTH administration on plasma and brain neurosteroid levels

The 3alpha-hydroxy ring A-reduced metabolite of progesterone, 3alpha-hydroxy-5alpha-pregnan-20-one (allopregnanolone) is among the most potent known ligands of the gamma aminobutyric acid (GABA) receptor, designated GABA-A, in the central nervous system. We determined by RIA serum levels of progesterone (PROG), 5-alpha-dihidroprogesterone (DHP) and allopregnanolone in male and female rats after corticotropin releasing hormone (CRH) and adrenocorticotropin hormone (ACTH) administration. Allopregnanolone was undetectable in plasma and brain of control males but detectable in plasma and brain of males injected with CRH and ACTH and of control and similarly treated females. Allopregnanolone increased in the plasma and brain after CRH and ACTH administration in all cases. The data demonstrate that the administration of CRH plus ACTH results in a rapid increase of the neuroactive steroid allopregnanolone in the brain of males and females to levels known to modulate GABA-A receptor function. Thus, stress could regulate neurosteroid biosynthesis via the hormones ACTH and CRH.

Crystalline dihydrotestosterone implants in the lateral septum of male rats. A positive effect on LH and FSH

Previous investigations in our laboratory have shown that testosterone implanted into the lateral septum in male rats increases LH and FSH secretion. However, it was unclear whether the effect of testosterone was direct via androgen receptor, or indirect via the estrogen receptor after conversion by aromatization to estradiol. To answer this question, we implanted either testosterone or the non-aromatizable androgen 5 alpha-dihydrotestosterone (DHT), into the lateral septum of adult male rats and measured plasma levels of LH and FSH by radioimmunoassay 2 days after implantation. Both testosterone and DHT significantly increased the plasma LH and FSH concentrations. Mean concentration of LH in control animals was 0.21 +/- 0.06 ng/ml, a figure that increased to 0.7 +/- 0.12 and 0.55 +/- 0.1 ng/ml after DHT or testosterone implantation respectively. Mean concentration of FSH in control animals was 1.5 +/- 0.3 ng/ml; this figure increased to 3 +/- 0.3 and 2.9 +/- 0.3 ng/ml after DHT or testosterone implantation. Neither plasma DHT (64.0 +/- 5.6 vs. 52 +/- 5 ng/100ml) nor plasma testosterone levels (4.1 +/- 0.38 vs. 3.3 +/- 0.18 ng/ml) were significantly affected by the implants. We conclude that androgens independently of conversion to estrogen acting in the lateral septum facilitates the release of LH and FSH.

Evidence of different actions of testosterone, estradiol, FSH, and LH on the growth axis

To study the possible role of sexual hormones, Testosterone (T), Estradiol (E2), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) on the growth axis, we examined the correlations between the sex, growth hormone (GH), insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP3), FSH, LH, T and E2, in growth retarded children ranging in age from 7 to 13 yr. All hormones were measured by Radioimmunoassay (RIA) in a pool of aliquots of samples obtained every 20 min over 12 h (overnight) in each child. Multivariate statistical analysis was performed. We have found: a) Thai only FSH concentrations were significantly higher in girls than in boys; b) A positive correlation between T-IGF-1; T-IGFBP3; FSH-LH; FSH-IGF-1; FSH-IGFBP3, LH-IGF-1, LH-IGFBP3 the sex-FSH; and the sex-IGFBP3 c) A high positive correlation between plasmatic E2 and IGF-1/IGFBP3 ratio (an index of free, active IGF-1). We concluded that the sex, FSH, LH, T and E2 influence the growth axis. The sex through IGFBP3; LH, FSH, and T through IGF1 and IGFBP3; E2 through the IGF-1/IGFBP3 ratio, an index of active IGF-1.

Effects of acute alcohol intoxication on growth axis in human adolescents of both sexes

We previously reported the deleterious effects of acute alcohol intoxication (AAI) on pituitary-gonadal and pituitary-adrenal axes hormones in human adolescents. In the present paper we studied the effects of AAI on the growth axis hormones, and the possible contribution of the insulin-glucose axis to the alcohol-induced dysfunction of the growth axis in human adolescents. Blood samples were drawn from adolescents that arrived at the emergency department with evident behavioural symptoms of drunkenness (AAI) or with nil consumption of alcohol (controls [C]). AAI produced in the adolescents of both sexes in our series: a decrease in growth hormone (GH) levels, without significant alteration of either insulin-like growth factor-I (IGF-I) or insulin-like growth factor binding protein-3 (IGFBP3); an increase in plasma glucose and a decrease in insulin in the female adolescents but not in the males. Males and females undergo a significant period of bone growth during adolescence. Growth axis hormones play an important role in the pubertal spurt. Thus, ethanol consumption during adolescence could have long-lasting deleterious effects on this aspect of development. In industrialised countries, around 35% of alcohol drinkers are under 16 years old, therefore the result of this study should be made known to adolescents and the appropriate authorities.

Safety evaluation of a recombinant myxoma-RHDV virus inducing horizontal transmissible protection against myxomatosis and rabbit haemorrhagic disease

We have recently developed a transmissible vaccine to immunize rabbits against myxomatosis and rabbit haemorrhagic disease based on a recombinant myxoma virus (MV) expressing the rabbit haemorrhagic disease virus (RHDV) capsid protein [Bárcena et al. Horizontal transmissible protection against myxomatosis and rabbit haemorragic disease using a recombinant myxoma virus. J. Virol. 2000;74:1114-23]. Administration of the recombinant virus protects rabbits against lethal RHDV and MV challenges. Furthermore, the recombinant virus is capable of horizontal spreading promoting protection of contact animals, thus providing the opportunity to immunize wild rabbit populations. However, potential risks must be extensively evaluated before considering its field use. In this study several safety issues concerning the proposed vaccine have been evaluated under laboratory conditions. Results indicated that vaccine administration is safe even at a 100-fold overdose. No undesirable effects were detected upon administration to immunosuppressed or pregnant rabbits. The recombinant virus maintained its attenuated phenotype after 10 passages in vivo.

Effects of acute alcohol intoxication on pituitary-gonadal axis hormones, pituitary-adrenal axis hormones, beta-endorphin and prolactin in human adolescents of both sexes

Teenage drinking continues to be a major problem in industrialized countries, where almost 35% of alcohol drinkers are under 16 years old. In the present paper we studied the effects of acute alcohol intoxication (AAI) on the pituitary-gonadal (PG) axis hormones, and the possible contribution of pituitary-adrenal (PA) axis hormones, beta-endorphin (BEND), and prolactin (PRL) to the alcohol-induced dysfunction of PG axis hormones. Blood samples were drawn from adolescents that arrived at the emergency department with evident behavioral symptoms of drunkenness (AAI) or with nil consumption of alcohol (controls [C]). Our results demonstrated that AAI produces in adolescents a high increase in plasma PRL, ACTH, and cortisol (F), and a contradictory behavior of testosterone (T) according to gender: plasma T was increased in females and decreased in males. ACTH and PRL correlated positively with F, dehydroepiandrosterone-sulphate (DHEAS) and T in females, which suggests that PRL and ACTH could synergistically stimulate adrenal androgen production. In contrast, the decrease in T and increase in BEND in males suggests that AAI could have an inhibitory effect on testicular T, perhaps mediated by BEND. The hormones studied are involved in the development of secondary sexual characteristics and the growth axis during adolescence. The deleterious effects of alcohol abuse should be made known to adolescents and the appropriate authorities.

Isolation of an attenuated myxoma virus field strain that can confer protection against myxomatosis on contacts of vaccinates

Twenty MV strains obtained from a survey of field strains currently circulating throughout Spain were analyzed for their virulence and horizontal spreading among rabbits by contact transmission. A virus strain with suitable characteristics to be used as a potential vaccine against myxomatosis in wild rabbit populations was selected. Following inoculation, the selected MV strain elicited high levels of MV specific antibodies and induced protection of rabbits against a virulent MV challenge. Furthermore, the attenuated MV was transmitted to 9 out of 16 uninoculated rabbits by contact, inducing protection against myxomatosis.

[Transmissible spongiform encephalopathies in animals]

INTRODUCTION

The transmissible spongiform encephalopathies affect several species of higher animals apart from man. Amongst these, undoubtedly the best known is that affecting cattle, since the association between consumption of beef and its derivatives and the appearance of a variant of Creutzfeldt-Jakob disease in humans has been established.

DEVELOPMENT

This type of pathology has been well known for many years in the ovine family, particularly in sheep and goats. In spite of the establishment of hypotheses linking the cause of the appearance of spongiform encephalopathy in cows with an interspecies jump of the disease between the ovine and bovine families, this has not yet been proved. Concomitant with the epidemic of bovine spongiform encephalopathy, other species of animals were reported to have been affected by an identical disease. These included farmed mink, deer, elks, cats and two species of exotic African ungulates (the nyala and the greater kudu). All cases were described in animals kept in captivity for human consumption. Thus it would seem that there was a common cause of the disease in all cases.

CONCLUSION

In this paper we describe the most relevant aspects of the appearance of this disorder in animals, including the symptoms, epidemiology and pathology typical of each specific condition.

Effect of estrogen-progestin replacement therapy on plasma lipids and lipoproteins in postmenopausal women

Serum levels of cholesterol (Chol), triglycerides (TG), low-density lipoprotein cholesterol (LDL) high-density lipoprotein cholesterol (HDL), both apolipoproteins A1 and B (Apo A1, Apo B), follicle-stimulating hormone (FSH) luteinizing hormone (LH), estradiol (E2), progesterone (P), testosterone (T) and steroid hormone binding globulin (SHBG) were measured in postmenopausal women, before and after four different estrogen-progestin replacement therapies. Each woman was her own control to avoid genetic or socioeconomic differences. Our results showed that serum E2 and TG significantly increased and serum FSH, LH, LDH, Apo B, and Chol significantly decreased after all treatments. Serum P and T did not significantly change after any of the treatments. HDL, Apo A1 and SHBG significantly increased in the groups treated with medroxiprogesterone acetate (MPA) but not in the group treated with Norgestrel. We conclude that estrogen-progestin replacement therapy in postmenopausal women leads to profound and beneficial changes in plasma lipids and lipoproteins and that treatments with cyclic or continuous MPA could provide greater protection against coronary heart disease (CHD).

Imported histoplasmosis in Spain

Histoplasma capsulatum is a dimorphic fungus endemic in the American continent but not in Europe, where cases are usually imported. Its favorite habitat is in warm humid soils. Guano from birds and bats enhance the sporulation of the mycelial phase.1 Man acquires H. capsulatum through inhalation of spores. Most people infected by this fungi remain asymptomatic, but around 10-50% can start an illness ranging from acute pulmonary histoplasmosis to chronic histoplasmosis. In both, there is close clinical resemblance to pulmonary tuberculosis. Immunodepressed patients undergo a more severe form of the disease, usually presenting in the acute disseminated form. We present seven immunocompetent patients with histoplasmosis acquired after traveling to several American countries.

Horizontal transmissible protection against myxomatosis and rabbit hemorrhagic disease by using a recombinant myxoma virus

We have developed a new strategy for immunization of wild rabbit populations against myxomatosis and rabbit hemorrhagic disease (RHD) that uses recombinant viruses based on a naturally attenuated field strain of myxoma virus (MV). The recombinant viruses expressed the RHDV major capsid protein (VP60) including a linear epitope tag from the transmissible gastroenteritis virus (TGEV) nucleoprotein. Following inoculation, the recombinant viruses induced specific antibody responses against MV, RHDV, and the TGEV tag. Immunization of wild rabbits by the subcutaneous and oral routes conferred protection against virulent RHDV and MV challenges. The recombinant viruses showed a limited horizontal transmission capacity, either by direct contact or in a flea-mediated process, promoting immunization of contact uninoculated animals.

Paradoxical behavior of the QT interval during exercise and recovery and its relationship with cardiac memory

BACKGROUND

Few studies have dealt with the behavior of the corrected (QTc) and uncorrected QT intervals during exercise and recovery.

HYPOTHESIS

Based on previously published dynamics of the QT interval during treadmill testing, this study attempted to reevaluate the computer-proposed underlying mechanisms of these dynamics and to determine whether the so-called memory phenomenon could be operative in some subjects without evidence of structural heart disease.

METHODS

This study included 42 unmedicated healthcare volunteers, 23 men and 19 women aged between 20 and 42 (mean 31.7) years. All had normal physical examinations, x-rays, and transthoracic echocardiograms. The electrocardiograms were also normal with 12-lead QT interval dispersions of < 90 ms.

RESULTS

During exercise and recovery, the behavior of the QT intervals permitted the categorization into two groups. In Group 1 (31/42; 73.8% of subjects) the uncorrected QT interval showed a biphasic pattern consisting of a gradual decrease during incremental exercise followed by a gradual increase during recovery. In contrast, the QTc interval had a triphasic pattern resulting from a slight increase during the early phase of exercise, a gradual decrease at the highest rates, and a final increase during recovery as the rate slowed to control values. In Group 2 (11/42; 36.2% of subjects) the behavior was considered as paradoxical since the uncorrected QT interval displayed in a triphasic pattern whereas the QTc interval yielded a tetraphasic pattern due to the fact that both showed a second decrease during recovery while the rate was decreasing.

CONCLUSIONS

Analysis of dynamics behavior of the QTc and the uncorrected QT intervals during exercise showed that some normal subjects had a paradoxical behavior which, because of its temporal relation to the phases of exercise, could be an expression of the so-called memory phenomenon.

Streptococcus pneumoniae bacteremia in a community hospital

We reviewed 71 consecutive patients with Streptococcus pneumoniae bacteremia. The patients were analyzed by age, sex, ethnic background, and clinical presentation. Laboratory data reviewed included a CBC count, electrolyte levels, liver function studies, chest radiograph, HIV status, a sputum culture and Gram's stain, and sensitivities for the S pneumoniae isolated. Modalities of therapy, response to treatment, and ultimate outcome were examined. Many of the patients with pneumococcal bacteremia did not have cough, fever, or chills. HIV positivity was a risk factor for pneumococcal infection although it was not associated with increased mortality. Mortality correlated with elderly status, leukopenia, and lack of fever. Many patients had symptoms suggestive of atypical pneumonia including myalgia and mental status change. Hyponatremia and hyperbilirubinemia were commonly noted.