Prevention of Haemophilus influenzae type b colonization by vaccination: correlation with serum anti-capsular IgG concentration

Concentrations of serum anti-Haemophilus influenzae type b (anti-Hib) capsular polysaccharide (CPS) >/=0.15 and >/=1.0 microgram/mL are widely used as surrogates for protection against invasive Hib disease. However, the relationship between serum anti-Hib CPS following immunization and protection against colonization is not known, making it difficult to evaluate new Hib vaccines or combination vaccines. In the Dominican Republic, nasopharyngeal swabs were collected from 546 9-month-old infants who had received Hib conjugate vaccine at ages 2, 4, and 6 months and from 600 unvaccinated infants of the same age. The prevalence of Hib colonization was lower among vaccinated infants than among unvaccinated infants (0.9% vs. 2.3%). Among vaccinated infants, protection against colonization was significantly correlated with anti-Hib CPS concentrations >/=5 microgram/mL 1 month following the third dose of vaccine. These results suggest that the concentration of serum anti-Hib CPS needed for protection against colonization is greater than that needed for protection for invasive disease.

Subjects with allergic reactions to drugs show in vivo polarized patterns of cytokine expression depending on the chronology of the clinical reaction

BACKGROUND

The mechanisms involved in adverse drug reactions with an immunologic basis (ADRIB) can be antibody dependent, mainly IgE or T cell dependent (sensitized T cells). These mechanisms are regulated by a number of cytokines, including IL-2, IL-4, IL-5, IFN-gamma, and TNF-alpha, which follow the classical T(H)1/T(H)2 immunologic paradigm. Although evidence for this has been seen in ex vivo studies, the results are heterogeneous, and few in vivo studies have been carried out in subjects with ADRIB.

OBJECTIVE

We studied a group of patients who experienced either immediate reactions (n = 10) or nonimmediate reactions (n = 9) to drugs to determine the cytokine pattern profile during the acute stage of the response, as well as after recovery.

METHODS

PBMCs were taken at different time intervals of 24 hours or less and 7, 15, and 30 days after the onset of the reaction, and the specific cytokine transcription and production were determined by using quantitative competitive RT-PCR and ELISA, respectively.

RESULTS

There was a transient polarized pattern corresponding to a T(H)1 response with IL-2, IFN-gamma, and TNF-alpha in nonimmediate reactions and to a T(H)2 response with IL-4 in immediate reactions.

CONCLUSIONS

This is the first in vivo demonstration of these T(H)1/T(H)2 patterns in subjects with ADRIB and confirms that an immunologic process is occurring related to the mechanisms involved in the pathologic manifestation. These findings are relevant to the understanding of the pathophysiologic mechanisms involved in ADRIB, suggesting that further studies in this direction are warranted.

Range of motion of the wrist: implications for designing computer input devices for the elderly

PURPOSE

The purpose of this study was to report normative values of the amplitude of joint wrist motions and grip strength for older age groups.

METHOD

Volunteers. (N = 147) were divided into four age groups, 60-69, 70-79, 80-89 and 90+ years, with a total of 62 men and 85 women. Maximum range motion values were obtained for wrist flexion, extension and ulnar deviation. In addition, grip strength measures were obtained for each participant.

RESULTS

In general, the strength and ROM values for the oldest participants in this study were lower than those of the younger age group (age 60 to 69) and significantly lower than those published for subjects between 25 and 54 years of age. Furthermore, across all age groups males were significantly stronger than females. However, females tended to have greater ROM than males, particularly for wrist extension and ulnar deviations. Joint ROM and grip strength declined significantly with age for both males and females. Comparisons with published data for younger subjects (age 25-35) indicate that a 60-69 year old male, will on average experience a decline in wrist flexion, extension and ulnar deviation of 12%, 41%, and 22% respectively. By age 90, an individual may be expected to have ROM values that are only approximately 60% of an average 30 year old individual.

CONCLUSION

The results suggest that the ageing population (particularly men) may face greater difficulty using an input device such as a mouse that relies on motions of the wrist. In addition, the reduced ROM of the wrist may put the elderly at greater risk of developing cumulative trauma disorders. The implications of these findings for the design of input devices are discussed.

Synchronous glucose-dependent [Ca(2+)](i) oscillations in mouse pancreatic islets of Langerhans recorded in vivo

Using microfluorescence in combination with image-analysis techniques we monitored intracellular calcium ([Ca(2+)](i)) dynamics in mouse islets of Langerhans loaded with fura-2 and recorded in vivo. [Ca(2+)](i) oscillates in the glycaemias range 5-10 mM, the duration of the oscillations being directly proportional to the blood glucose concentration. The analysis of different areas within the same islet shows that [Ca(2+)](i) oscillations are synchronous throughout the islet. These results show that in vivo, individual islets of Langerhans behave as a functional syncytium and suggest the existence of secretory pulses of insulin.

Proton magnetic resonance spectroscopy of the medial prefrontal cortex in patients with deficit schizophrenia: preliminary report

OBJECTIVE

Proton magnetic resonance spectroscopy (1H-MRS) was used to study medial prefrontal metabolic impairments in schizophrenic patients with the deficit syndrome.

METHOD

The subjects were 22 schizophrenic patients categorized as deficit (N=5) or nondeficit (N=17) and 21 healthy subjects. (1)H-MRS was performed for the right and the left medial prefrontal cortex.

RESULTS

The patients with the deficit syndrome had significantly lower ratios of N-acetylaspartate to creatine plus phosphocreatine than did the healthy subjects or nondeficit patients.

CONCLUSIONS

As N-acetylaspartate levels could reflect neuronal density and/or viability, this finding suggests a neuronal loss in the medial prefrontal cortex of deficit patients.

Evaluation of the polymerase chain reaction for the detection of Mycobacterium tuberculosis

The development of nucleic acid-based technologies has improved the sensitivity, specificity and speed of detection of Mycobacterium tuberculosis in clinical samples. Both commercially available and 'in-house' polymerase chain reaction (PCR) systems are in use, and a significant number of reports compare such systems with more traditional diagnostic tools for tuberculosis. Few studies, however, have focused on the reproducibility of the results when submitting a sample batch to PCR in different laboratories, especially in developing countries. Consequently, PCR results obtained from six laboratories in six different Latin American countries for samples reconstituted with defined amounts of M. tuberculosis cells were evaluated. Each laboratory used specific conditions of sample processing, nucleic acid amplification and amplicon detection. Analysis of results allowed large differences in sensitivity and specificity to be observed. We conclude that in its present setting, in-house PCR cannot be used as a single diagnostic tool for tuberculosis, and that special care needs to be taken upon interpretation of results by inclusion of a proper number of positive and negative controls.

[Magnetic resonance spectroscopy in schizophrenia]

Numerous studies have shown alterations of some structures and/or cerebral functions in patients with schizophrenia. However, the nature of the neurobiological process which could be at the origin of schizophrenic symptoms is still unknown. Magnetic resonance spectroscopy (MRS) is a unique technique which allows us to estimate the concentrations of endogenous substances which contain natural paramagnetic nuclei such as phosphorus (31P) and hydrogen (proton or 1H). The non invasive character of this technique, the absence of side effects, and the possibility of repetitive evaluations allowing for longitudinal studies, make possible MRS studies on the in vivo cerebral metabolism in schizophrenia. The prefrontal cortex, the hippocampus and the basal ganglia have all been implicated in the pathophysiology of schizophrenia. Therefore these brain regions have been frequently studied using MRS. Both proton and phosphorus spectroscopy have been used to study schizophrenia. Compounds that are detectable by 1H-MRS include N-acetyl aspartate (NAA), choline (Cho), creatine (Cr) and myo-inositol (ml). A deficit in NAA has been consistently shown in both the frontal and temporal lobes suggesting neuronal loss in these areas. Compounds detectable by 31P-MRS include phosphomonoesters (PMEs) and phosphodiesters (PDEs), which largely represent metabolites generated by lipid turnover. 31P-MRS can also detect certain energy-containing phosphorus metabolites such as phosphocreatine (PCr) and nucleotide triphosphates. Decreased levels of PMEs and increased levels of PDEs have been consistently described in the prefrontal lobes suggesting an alteration of phospholipid metabolism. The purpose of this review is to summarize the research on schizophrenia using MRS, to show the utility of this technique in understanding schizophrenia.

Serum anion gap in the differential diagnosis of metabolic acidosis in critically ill newborns

OBJECTIVES

To determine in critically ill newborn infants (1) the range of the serum anion gap without metabolic acidosis and (2) whether the serum anion gap can be used to distinguish newborns with lactic acidosis from those with hyperchloremic metabolic acidosis.

STUDY DESIGN

Umbilical arterial blood gases and serum electrolyte and lactate concentrations were measured simultaneously in 210 samples from 63 infants over the first week of life. Metabolic acidosis was defined as a blood base deficit (BD) >4 mmol/L. The anion gap was calculated as [Na(+)] - [C1(-)] - [TCO (2)]. Lactic acidosis was defined as a serum lactate concentration >2 SD above the mean serum lactate concentration in samples without metabolic acidosis.

RESULTS

In 89 blood samples with BD <4 mmol/L, serum lactate concentration decreased with postnatal age (r = 0.51). The upper limit of serum lactate concentration was 3.8 mmol/L at less than 48 hours, 2.4 mmol/L between 48 and 96 hours, and 1.5 mmol/L for infants greater than 96 hours of age. The mean serum anion gap +/- 2 SD in 174 samples without lactic acidosis was 8 +/- 4 mmol/L; in 36 samples with lactic acidosis it was 16 +/- 9 mmol/L (P <.0001). Serum anion gap and lactate concentration were poorly correlated for samples without lactic acidosis (r = 0.04) but highly correlated in those with lactic acidosis (r = 0.81, P <.0001). None of the 85 samples with metabolic acidosis but without lactic acidosis had an anion gap >16 mmol/L; only 4 of 36 samples with lactic acidosis had an anion gap <8 meq/L. However, 25 of 36 samples with lactic acidosis had serum anion gaps of 8 to 16 mmol/L.

CONCLUSION

In the presence of metabolic acidosis, a serum anion gap >16 mmol/L is highly predictive of lactic acidosis; a serum anion gap <8 is highly predictive of the absence of lactic acidosis; an anion gap = 8 - 16 mmol/L has no use in the differential diagnosis of metabolic acidosis in the critically ill newborn.

6-oxa isosteres of anacardic acids as potent inhibitors of bacterial histidine protein kinase (HPK)-mediated two-component regulatory systems

A series of 6-oxa isosteres of anacardic acids (6-higher alkyl/alkenyl-2-hydroxybenzoic acids) was synthesised and several members were discovered to be among the most potent inhibitors (IC50 values < or = 5 microM) of the bacterial two-component regulatory systems, KinA/SpoOF and NRII/NRI, reported to date. The Gram-positive antibacterial activity in selected strains is also presented.

A functional interaction between the histone deacetylase Rpd3 and the corepressor groucho in Drosophila development

The Drosophila gene groucho (gro) encodes a transcriptional corepressor that has critical roles in many development processes. In an effort to illuminate the mechanism of Gro-mediated repression, we have employed Gro as an affinity reagent to purify Gro-binding proteins from embryonic nuclear extracts. One of these proteins was found to be the histone deacetylase Rpd3. Protein-protein interaction assays suggest that Gro and Rpd3 form a complex in vivo and that they interact directly via the glycine/proline rich (GP) domain in Gro. Cell culture assays demonstrate that Rpd3 potentiates repression by the GP domain. Furthermore, experiments employing a histone deacetylase inhibitor, as well as a catalytically inactive form of Rpd3, imply that histone deacetylase activity is required for efficient Gro-mediated repression. Finally, mutations in gro and rpd3 have synergistic effects on embryonic lethality and pattern formation. These findings support the view that Gro mediates repression, at least in part, by the direct recruitment of the histone deacetylase Rpd3 to the template, where it can modulate local chromatin structure. They also provide evidence for a specific role of Rpd3 in early development.

Epidemiological study of the prevalence of allergic reactions to Hymenoptera in a rural population in the Mediterranean area

BACKGROUND

Systemic allergic reactions to Hymenoptera venom occur in a percentage that varies from 0.4 to 3.3%. Epidemiological studies indicate that from 15 to 25% of the general population can be sensitized to different Hymenoptera venom as well as the fact that the degree of exposure may be related to the prevalence found in those studies.

OBJECTIVE

The objective of this study was to evaluate the prevalence of insect sting allergy and the venom sensitization in a rural population to three Hymenoptera previously found in the area: Polistes dominulus (Pd), Vespula germanica (Vg) and honey bee (Hb).

METHODS

A rural community located in the south-east of Spain, close to the Mediterranean Sea, was selected since the stinging Hymenoptera having been previously identified. A random sample of 310 subjects from the village census was studied. A questionnaire and a serum sample were obtained from every patient. The evaluation was conducted by a family doctor, who focused on the reactions to Hymenoptera sting, age, sex, occupation, atopia, previous Hymenoptera sting, stinging insect, interval to last sting and average stings per year. RAST to Hymenoptera venoms were also determined.

RESULTS

The prevalence of systemic reactions was 2.3% (57.6% of them had a positive RAST). Large local reactions were found in 26.4% (only 28.5% of them had a positive RAST). Asymptomatic sensitization (positive RAST) was observed in 16.4% of subjects without reaction. Only a weak correlation between subjects with less than 3 years' interval to last sting exposure and positive RAST results was noted, whether they presented with a clinical reaction or not (P < 0.05).

CONCLUSIONS

The prevalence of systemic sting reactions in our rural community is higher than other general populations in the same Mediterranean area, and similar to other rural populations studied. The degree of exposure influences not only the prevalence found but also the detection of specific serum IgE.

Long-term follow-up of chimpanzees inoculated with the first infectious clone for hepatitis C virus

Two chimpanzees (Ch1535 and Ch1536) became infected with hepatitis C virus (HCV) following intrahepatic inoculation with RNA transcribed from a full-length cDNA clone of the virus. Both animals were persistently infected and have been followed for 60 weeks. They showed similar responses to infection, with transient liver enzyme elevations and liver inflammatory responses, which peaked at weeks 17 (Ch1535) and 12 (Ch1536) postinoculation (p.i.). Antibody responses to structural and nonstructural proteins were first detected at weeks 13 (Ch1535) and 10 (Ch1536) p.i. Serum RNA titers increased steadily during the first 10 to 13 weeks but decreased sharply in both animals following antibody and inflammatory responses. Despite direct evidence of humoral immune responses to multiple viral antigens, including hypervariable region 1 (HVR1), both animals remained chronically infected. Detailed sequence analysis of serum HCV RNA revealed no change in the majority HVR1 sequence in Ch1535 and a single-amino-acid mutation in Ch1536, with very little clonal variation in either animal. Full-length genome analysis at week 60 revealed several amino acid substitutions localized to antigens E1, E2, p7, NS3, and NS5. Of these, 55.6 and 40% were present as the majority sequence in serum RNA isolated at week 26 p.i. (Ch1535) and week 22 p.i. (Ch1536), respectively, and could represent immune escape mutations. Mutations accumulated at a rate of 1.57 x 10(-3) and 1.48 x 10(-3) nucleotide substitutions/site/year for Ch1535 and Ch1536, respectively. Taken together, these data indicate that establishment of a persistent HCV infection in these chimpanzees is not due to changes in HVR1; however, the possibility remains that mutations arising in other parts of the genome contributed to this persistence.

Glucose-dependent stimulatory effect of glucagon-like peptide 1(7-36) amide on the electrical activity of pancreatic beta-cells recorded in vivo

The stimulatory effect of the glucagon-like peptide (GLP)-1(7-36) amide on electrical activity in pancreatic b-cells recorded in vivo was studied. The injection of GLP-1 produces a lengthening of the active phase with respect to the silent phase, leading to a stimulation of insulin release, which produces a secondary decrease in blood glucose concentration and eventually, to the hyperpolarization of the membrane at a blood glucose level of approximately 5 mmol/l. The injection of GLP-1 at a glycemic level <5 mmol/l does not stimulate electrical activity. This is in contrast to the effect of tolbutamide, which stimulates electrical activity at low glucose concentrations. These results demonstrate that in vivo, the stimulatory effect of GLP-1 on insulin secretion is at least partially mediated by its effect on beta-cell electrical activity. Furthermore, the glucose dependence of the effect confers to GLP-1, a security factor that supports its potential use in the treatment of type 2 diabetes.

Comparison of efficacies of oral levofloxacin and oral ciprofloxacin in a rabbit model of a staphylococcal abscess

Oral levofloxacin was compared to oral ciprofloxacin in a Staphylococcus aureus subcutaneous abscess model in rabbits. Rabbits were surgically prepared with subcutaneous wiffle balls (43 mm in diameter) and allowed to recover for 4 to 6 weeks. Rabbits were infected by direct injection into the capsule with S. aureus ATCC 29213 (5 x 10(5) CFU) and were allowed to remain infected for 8 days before the initiation of anti-infective treatment. Efficacy was determined by assessing the bacterial load within the capsule over a 10-day treatment period. In single-dose pharmacokinetic studies in infected rabbits, similar area under the concentration-time curve/MIC ratios were obtained in the plasma and abscess fluid for levofloxacin at 45 mg/kg of body weight and ciprofloxacin at 200 mg/kg of body weight. Similar efficacies were seen with levofloxacin at 45 mg/kg/day and ciprofloxacin 400 mg/kg/day by day 10. In this model, levofloxacin was significantly more efficacious than ciprofloxacin (P < 0.01).

Characterization of two novel propachlor degradation pathways in two species of soil bacteria

Propachlor (2-chloro-N-isopropylacetanilide) is an acetamide herbicide used in preemergence. In this study, we isolated and characterized a soil bacterium, Acinetobacter strain BEM2, that was able to utilize this herbicide as the sole and limiting carbon source. Identification of the intermediates of propachlor degradation by this strain and characterization of new metabolites in the degradation of propachlor by a previously reported strain of Pseudomonas (PEM1) support two different propachlor degradation pathways. Washed-cell suspensions of strain PEM1 with propachlor accumulated N-isopropylacetanilide, acetanilide, acetamide, and catechol. Pseudomonas strain PEM1 grew on propachlor with a generation time of 3.4 h and a Ks of 0.17 +/- 0.04 mM. Acinetobacter strain BEM2 grew on propachlor with a generation time of 3.1 h and a Ks of 0.3 +/- 0.07 mM. Incubations with strain BEM2 resulted in accumulation of N-isopropylacetanilide, N-isopropylaniline, isopropylamine, and catechol. Both degradative pathways were inducible, and the principal product of the carbon atoms in the propachlor ring was carbon dioxide. These results and biodegradation experiments with the identified metabolites indicate that metabolism of propachlor by Pseudomonas sp. strain PEM1 proceeds through a different pathway from metabolism by Acinetobacter sp. strain BEM2.

Determination of IgE antibodies to the benzylpenicilloyl determinant: a comparison of the sensitivity and specificity of three radio allergo sorbent test methods

The quantitation of in vitro IgE antibodies to the benzylpenicilloyl determinant (BPO) is a useful tool for evaluating suspected penicillin allergic subjects. Although many different methods have been employed, few studies have compared their diagnostic specificity and sensitivity. In this study, the sensitivity and specificity of three different radio allergo sorbent test (RAST) methods for quantitating specific IgE antibodies to the BPO determinant were compared. Thirty positive control sera (serum samples from penicillin allergic subjects with a positive clinical history and a positive penicillin skin test) and 30 negative control sera (sera from subjects with no history of penicillin allergy and negative skin tests) were tested for BPO-specific IgE antibodies by RAST using three different conjugates coupled to the solid phase: benzylpenicillin conjugated to polylysine (BPO-PLL), benzylpenicillin conjugated to human serum albumin (BPO-HSA), and benzylpenicillin conjugated to an aminospacer (BPO-SP). Receiver operator control curves (ROC analysis) were carried out by determining different cut-off points between positive and negative values. Contingence tables were constructed and sensitivity, specificity, negative predictive values (PV-), and positive predictive values (PV+) were calculated. Pearson correlation coefficients (r) and intraclass correlation coefficients (ICC) were determined and the differences between methods were compared by chi 2 analysis. Analysis of the areas defined by the ROC curves showed statistical differences among the three methods. When cut-off points for optimal sensitivity and specificity were chosen, the BPO-HSA assay was less sensitive and less specific and had a lower PV- and PV+ than the BPO-PLL and BPO-SP assays. Assessment of r and ICC indicated that the correlation was very high, but the concordance between the PLL and SP methods was higher than between the PLL and HSA or SP and HSA methods. We conclude that for quantitating IgE antibodies by RAST to the BPO determinant, BPO-SP or BPO-PLL conjugates offer advantages in sensitivity and specificity compared with BPO-HSA. These results support and extend previous in vitro studies by our group and highlight the importance of the carrier for RAST assays.

Dorsal-mediated repression requires the formation of a multiprotein repression complex at the ventral silencer

Dorsal functions as both an activator and repressor of transcription to determine dorsoventral fate in the Drosophila melanogaster embryo. Repression by Dorsal requires the corepressor Groucho (Gro) and is mediated by silencers termed ventral repression regions (VRRs). A VRR in zerknüllt (zen) contains Dorsal binding sites as well as an essential element termed AT2. We have identified and purified an AT2 DNA binding activity in embryos and shown it to consist of cut (ct) and dead ringer (dri) gene products. Studies of loss-of-function mutations in ct and dri demonstrate that both genes are required for the activity of the AT2 site. Dorsal and Dri both bind Gro, acting cooperatively to recruit it to the DNA. Thus, ventral repression may require the formation of a multiprotein complex at the VRR. This complex includes Dorsal, Gro, and additional DNA binding proteins, which appear to convert Dorsal from an activator to a repressor by enabling it to recruit Gro to the template. By showing how binding site context can dramatically alter transcription factor function, these findings help clarify the mechanisms responsible for the regulatory specificity of transcription factors.

Increased levels of free fatty acids in fasted mice stimulate in vivo beta-cell electrical activity

The electrical activity of pancreatic beta-cells in 48-h fasted mice has been recorded in vivo. Their electrical activity is exceedingly high at low levels of blood glucose when compared with control animals. For example, at a blood glucose concentration of 4.5 mmol/l, at which beta-cells are permanently hyperpolarized in control animals, fasted animals show continuous spiking activity. In fasted animals, hyperpolarization only occurs at glycemias below 2.2 mmol/l. As in fed animals, the electrical activity in fasted mice can be decreased or suppressed by the injection of diazoxide, indicating the participation of K(ATP) channels. The treatment of fasted animals with nicotinic acid, an inhibitor of lipolysis, produces a decrease in the levels of free fatty acids (FFAs) and a decrease in electrical activity, thereby restoring the dose-response curve for glucose in fasted animals to values close to those found in fed animals. Conversely, the injection of palmitic acid produces an increase in electrical activity without a change in blood glucose. These results point to FFAs as important regulators of electrical activity during fasting in vivo. They also indicate a dissociation of electrical activity and insulin release in fasted animals, since an increase in electrical activity is not associated with increased insulin secretion.