Multimilliwatt ultrashort pulses continuously tunable in the visible from a compact fiber source

We report on a single-pass device that efficiently converts the broadband near-infrared output from a femtosecond fiber laser into a narrow spectrum in the visible. With fan-out poled MgO:LiNbO3 we obtain sub-picosecond, continuously tunable pulses in the 520-700 nm range. Conversion efficiencies as high as 30% are observed at typical pump power levels of 30 mW, corresponding to average output powers up to 9.5 mW. The specifications of our device are ideal for applications in confocal microscopy and frequency metrology.

Comparison of atazanavir with lopinavir/ritonavir in patients with prior protease inhibitor failure: a randomized multinational trial

OBJECTIVES

To compare change from baseline in HIV RNA and fasting low-density lipoprotein (LDL) cholesterol levels in protease inhibitor (PI)-experienced patients receiving unboosted atazanavir 400 mg once daily versus lopinavir 400 mg boosted with ritonavir 100 mg twice daily, with two nucleoside reverse transcriptase inhibitors (NRTIs). Secondary objectives included virologic response, CD4 cell count changes, other lipid changes, safety, and tolerability.

METHODS

Randomized, open-label, multinational, 48-week study in patients with one PI-regimen failure, HIV RNA > or = 1000 copies/mL, and CD4 count > or = 50 cells/mm3.

RESULTS

Three hundred patients were randomized; 290 treated (144 atazanavir, 146 lopinavir/ritonavir). Lopinavir/ritonavir resulted in a significantly greater reduction in HIV RNA than unboosted atazanavir (-2.02 vs -1.59 log10 copies/mL, p < 0.001) at week 48. Secondary efficacy endpoints also favored lopinavir/ritonavir; the differences in efficacy between regimens were also observed in secondary analyses comparing those subjects who were susceptible and those subjects who were resistant to their respective PIs at baseline. However, both regimens were equally effective in subjects who had no baseline NRTI mutations. From baseline to week 48, atazanavir resulted in either no change or decreases in fasting LDL cholesterol, total cholesterol, and fasting triglycerides (-6%, -2%, and +1%), whereas lopinavir/ritonavir resulted in increases (+3%, +12%, and +53%) (p < 0.05, all between-treatment comparisons). Fewer patients were administered lipid-lowering therapy in the atazanavir arm (6% vs 20% for lopinavir/ritonavir). Both regimens were safe and well tolerated.

CONCLUSIONS

While both treatments demonstrated good antiviral efficacy, relatively greater antiviral suppression was observed with lopinavir/ritonavir. In those patients with no NRTI mutations at baseline, both regimens demonstrated comparable virologic suppression. Atazanavir-treated patients demonstrated a superior lipid profile and required less frequent lipid-lowering treatment.

Bacillus subtilis locus encoding a killer protein and its antidote

We have isolated mutations that block sporulation after formation of the polar septum in Bacillus subtilis. These mutations were mapped to the two genes of a new locus, spoIIS. Inactivation of the second gene, spoIISB, decreases sporulation efficiency by 4 orders of magnitude. Inactivation of the first gene, spoIISA, has no effect on sporulation but it fully restores sporulation of a spoIISB null mutant, indicating that SpoIISB is required only to counteract the negative effect of SpoIISA on sporulation. An internal promoter ensures the synthesis of an excess of SpoIISB over SpoIISA during exponential growth and sporulation. In the absence of SpoIISB, the sporulating cells show lethal damage of their envelope shortly after asymmetric septation, a defect that can be corrected by synthesizing SpoIISB only in the mother cell. However, forced synthesis of SpoIISA in exponentially growing cells or in the forespore leads to the same type of morphological damage and to cell death. In both cases protection against the killing effect of SpoIISA can be provided by simultaneous synthesis of SpoIISB. The spoIIS locus is unique to B. subtilis, and since it is completely dispensable for sporulation its physiological role remains elusive.

T2Rs function as bitter taste receptors

Bitter taste perception provides animals with critical protection against ingestion of poisonous compounds. In the accompanying paper, we report the characterization of a large family of putative mammalian taste receptors (T2Rs). Here we use a heterologous expression system to show that specific T2Rs function as bitter taste receptors. A mouse T2R (mT2R-5) responds to the bitter tastant cycloheximide, and a human and a mouse receptor (hT2R-4 and mT2R-8) responded to denatonium and 6-n-propyl-2-thiouracil. Mice strains deficient in their ability to detect cycloheximide have amino acid substitutions in the mT2R-5 gene; these changes render the receptor significantly less responsive to cycloheximide. We also expressed mT2R-5 in insect cells and demonstrate specific tastant-dependent activation of gustducin, a G protein implicated in bitter signaling. Since a single taste receptor cell expresses a large repertoire of T2Rs, these findings provide a plausible explanation for the uniform bitter taste that is evoked by many structurally unrelated toxic compounds.

A novel family of mammalian taste receptors

In mammals, taste perception is a major mode of sensory input. We have identified a novel family of 40-80 human and rodent G protein-coupled receptors expressed in subsets of taste receptor cells of the tongue and palate epithelia. These candidate taste receptors (T2Rs) are organized in the genome in clusters and are genetically linked to loci that influence bitter perception in mice and humans. Notably, a single taste receptor cell expresses a large repertoire of T2Rs, suggesting that each cell may be capable of recognizing multiple tastants. T2Rs are exclusively expressed in taste receptor cells that contain the G protein alpha subunit gustducin, implying that they function as gustducin-linked receptors. In the accompanying paper, we demonstrate that T2Rs couple to gustducin in vitro, and respond to bitter tastants in a functional expression assay.

Analysis of frozen sections of intraoperative specimens obtained at the time of reoperation after hip or knee resection arthroplasty for the treatment of infection

BACKGROUND

Despite the effectiveness of a two-stage exchange protocol for the treatment of deep periprosthetic infection, infection can persist after resection arthroplasty and treatment with antibiotics, leading to a failed second-stage reconstruction. Intraoperative analysis of frozen sections has been shown to have a high sensitivity and specificity for the identification of infection at the time of revision arthroplasty; however, the usefulness of this test at the time of reoperation after resection arthroplasty and treatment with antibiotics is, to our knowledge, unknown.

METHODS

The medical records of sixty-four consecutive patients who had had a resection arthroplasty of either the knee (thirty-three patients) or the hip (thirty-one patients) and had had intraoperative analysis of frozen sections of periprosthetic tissue obtained at the time of a second-stage operation were reviewed. The mean interval between the resection arthroplasty and the attempted reimplantation was nineteen weeks. The results of the intraoperative analysis of the frozen sections were compared with those of analysis of permanent histological sections of the same tissues and with those of intraoperative cultures of specimens obtained from within the joint. The findings of the analyses of the frozen sections and the permanent histological sections were considered to be consistent with acute inflammation and infection if a mean of ten polymorphonuclear leukocytes or more per high-power field (forty times magnification) were seen in the five most cellular areas.

RESULTS

The intraoperative frozen sections of the specimens from two patients (one of whom was considered to have a persistent infection) met the criteria for acute inflammation. Four patients were considered to have a persistent infection on the basis of positive intraoperative cultures or permanent histological sections. Overall, intraoperative analysis of frozen sections at the time of reimplantation after resection arthroplasty had a sensitivity of 25 percent (detection of one of four persistent infections), a specificity of 98 percent, a positive predictive value of 50 percent (one of two), a negative predictive value of 95 percent, and an accuracy of 94 percent.

CONCLUSIONS

A negative finding on intraoperative analysis of frozen sections has a high predictive value with regard to ruling out the presence of infection; however, the sensitivity of the test for the detection of persistent infection is poor.

Putative mammalian taste receptors: a class of taste-specific GPCRs with distinct topographic selectivity

Taste represents a major form of sensory input in the animal kingdom. In mammals, taste perception begins with the recognition of tastant molecules by unknown membrane receptors localized on the apical surface of receptor cells of the tongue and palate epithelium. We report the cloning and characterization of two novel seven-transmembrane domain proteins expressed in topographically distinct subpopulations of taste receptor cells and taste buds. These proteins are specifically localized to the taste pore and are members of a new group of G protein-coupled receptors distantly related to putative mammalian pheromone receptors. We propose that these genes encode taste receptors.

Fractal organization of the pointwise correlation dimension of the heart rate

OBJECTIVE

To depict and quantify the degree of organization of the heart rate variability (HRV) in normal subjects.

METHODS

A modified algorithm was created to estimate series of 'point-dimensions' (PD2) from interbeat (R-R) interval series of 10 healthy subjects (21-56 years). Our innovation is twofold: (i) we quantified instances of low-dimensional chaos, random fluctuations, and those for which our method failed to provide either (due to poor statistics); (ii) consecutive subepochs of PD2s underwent a relative dispersion (RD) analysis, yielding an index (D) which quantifies the dynamical organization of the heart rate generator.

RESULTS

The mean values of PD2 series varied between 4.58 and 5.88 (mean+/-SD= 5.21+/-0.41, n = 10). For group 1 (21-30 years, n = 6) we found an averaged PD2 of 5.49+/-0.27, while for group 2 (47-56 years, n = 4) PD2 averaged 4.79+/-0.17. The RD analysis performed for subepochs of PD2s yielded both instances obeying fractal scaling (D < 1.5) and stochasticity (D > 1.5). The average D for group 1 was 1.39+/-0.04 (14 subepochs) and for group 2, 1.20+/-0.008 (8 subepochs). Paired t-test and Hartley F-max test for comparison between D values and homogeneity of variance between the two groups were performed, yielding P-values 0.004 and 0.02, respectively.

CONCLUSIONS

The complexity of the HRV seems to be modulated by a non-random fractal mechanism of a 'hyperchaotic' system, i.e. it can be hypothesized to contain more than one attractor. Also, our results support the 'chaos hypothesis' put forth recently, namely, the complexity of the cardiovascular dynamics is reduced with aging. The index of relative dispersion of the dimensional complexity has to be tested in various clinico-pathological settings, in order to corroborate its value as a potential new physiological measure.

Comparative efficacy of two angiotensin II receptor antagonists, irbesartan and losartan in mild-to-moderate hypertension. Irbesartan/Losartan Study Investigators

The primary objectives of this double-blind study were to compare the antihypertensive efficacy and tolerability of irbesartan and losartan, two angiotensin II (AT1 subtype) receptor antagonists with different pharmacokinetic profiles in patients with mild-to-moderate hypertension. Both drugs are approved for once-daily use (although losartan may also be prescribed twice-daily). After a placebo lead-in, 567 patients were randomized (1:1:1:1) to once-daily therapy with placebo, 100 mg losartan, 150 mg irbesartan, or 300 mg irbesartan for 8 weeks. Treatment groups had comparable demographic and baseline characteristics. After 8 weeks of treatment, reductions from baseline in trough seated diastolic blood pressure (SeDBP) and trough seated systolic blood pressure (SeSBP) with 300 mg irbesartan were greater than with 100 mg losartan (P < .01 for both comparisons), by 3.0 and 5.1 mm Hg, respectively; larger reductions were also demonstrated at weeks 1 and 4 (P < .01 and P = .017, respectively, for SeDBP). Throughout the study, the antihypertensive effect of 150 mg irbesartan did not differ significantly from that of 100 mg losartan. All therapies were well tolerated. The 300 mg dose of irbesartan was associated with the lowest incidence of adverse events (AE) and discontinuations because of AE. This study demonstrates that the maximally effective once-daily doses of two different AT1 receptor antagonists may result in clinically significant differences in blood pressure reductions, and therefore highlights the potential importance of the pharmacokinetic and pharmacodynamic differences between these two members of this class.

Transference: co-constructed or brought to the interaction?

Contemporary understandings of transference diverge around the issue of whether transference is co-constructed by both parties to the analytic interaction or brought to it by each participant. Examining the evolution of the concept of transference distills some of the issues inherent in this controversy. It is suggested that each of these conceptualizations contributes something essential to the development of a broader picture of the way transference functions in the clinical setting. If transference is viewed as a process operating along a continuum of repression, both co-construction of the interaction and the primitive wishes, fears, and fantasies brought to the interaction can be parsimoniously accounted for. Adaptive and archaic transference activity are distinguished, and the two dimensions of transference, dynamically interconnected, are shown to be essential aspects of analytic understanding.

Structural relationship between a bacterial developmental protein and eukaryotic PP2C protein phosphatases

Bacillus subtilis SpoIIE is a Ser protein phosphatase whose action on the phosphoprotein SpoIIAA triggers the cell type-specific activation of a sporulation transcription factor. Here we report that SpoIIE displays sequence similarity to the PP2C family of eukaryotic Ser/Thr protein phosphatases, and that residues common to these proteins are required for the function of both SpoIIE and TPD1, a yeast PP2C. These findings suggest that SpoIIE and the PP2C protein phosphatases are structurally related, and reveal a striking formal similarity between the SpoIIAA regulatory circuit and that of mammalian mitochondrial pyruvate dehydrogenase. This similarity may reflect an evolutionarily conserved mechanism of biological regulation based on the interplay of His protein kinase-like Ser kinases and PP2C-like protein phosphatases.

Oil bioremediation using insoluble nitrogen source

Oil bioremediation is limited by the availability of nitrogen and phosphorous, which are needed by the bacteria and not present in sufficient amounts in hydrocarbons. The supply of these two essential elements as water-soluble salts presents several problems. These include the rapid dilution of the salts in the large volumes of polluted land or water and their utilization by other bacteria that do not degrade oil. In addition, increasing the concentration of mobile nitrogen creates further environmental problems. The use of hydrophobic sources of nitrogen and phosphorous that have a low water solubility can overcome these problems. We have studied one such compound. F-1, that is not used by most bacteria but serves as a good nitrogen and phosphorous source for those bacterial strains that are capable of utilizing it. We have shown that bacteria using F-1 do not cross-feed other bacterial strains. Moreover, when the concentration of the pollutant is sufficiently reduced, the multiplication of the bacteria slows down until they become a negligible fraction of the bacterial population. Chemical analysis indicated that following a 28-day treatment of Alaskan crude oil, most of the hydrocarbons, including polycyclic aromatics, are degraded to undetectable levels. The C34 and C35 components were also degraded, although their degradation was not completed within this time period. In treatment of a sandy beach that was accidentally polluted with crude heavy oil, about 90% degradation was obtained within about 4 months at an outside average temperature of 5 -10 degrees C.

Selected risk factors in pediatric adenotonsillectomy

OBJECTIVE

To evaluate the ability of a set of cost-effective criteria to identify before surgery the pediatric patients in whom perioperative respiratory compromise is most likely to develop after adenotonsillectomy.

SETTING

A children's hospital medical center.

DESIGN

Prospective study using preoperative parental questionnaires and perioperative respiratory status documentation.

PATIENTS

All patients scheduled at the outpatient clinic were eligible.

MAIN OUTCOME MEASURE

The development of respiratory compromise as defined by at least 1 of the following occurring more than 2 hours after surgery: an oxygen desaturation level of less than 90%, an obstructive breathing pattern, or respiratory distress requiring intervention.

RESULTS

The risk of respiratory compromise was significantly increased in patients who were younger than 3 years (P < .001) and in those who had neuromuscular disorders (P < .05), chromosomal abnormalities (P < .005), difficulty in breathing during sleep (P < .005), restless sleep (P < .01), loud snoring with apnea (P < .05), or an upper respiratory tract infection within 4 weeks of surgery (P = .005). Respiratory compromise did not develop in any patients who did not snore (P < .05).

CONCLUSIONS

A complete history that includes symptoms suggestive of sleep apnea will assist in the preoperative identification of pediatric patients most at risk for perioperative respiratory compromise after undergoing adenotonsillectomy. Such patients might benefit from overnight observation in a hospital setting. However, when snoring is absent, outpatient surgery is appropriate, as the risk of respiratory compromise is minimal.

Free association and analytic neutrality: the basic structure of the psychoanalytic situation

This paper re-examines within a contemporary context an essential foundation of classical technique, the psychoanalytic situation. Defined in terms of basic elements of psychoanalytic relatedness which make possible the most profound exploration of human motivation, its core structure is viewed as an extraordinary interpersonal arrangement anchored by two clearly differentiated yet complimentary ways of relating: free-association and analytic neutrality. The patient's role, organized by the prerequisites of expressive freedom, is counter posed with the psychoanalyst's, which is structured to empower listening and understanding. Elaborating the parameters of this unique relationship, the authors emphasize the synergic effects of each participants' activity in creating a vehicle for destabilizing neurotic equilibrium. An extensive discussion of analytic neutrality, conceived as guiding ideal that informs all the analyst's attitudes and actions in the exploration of psychic reality, is presented. Specifically, the authors distinguish three essential dimensions which bear upon the interactive process: neutrality with regard to conflict, neutrality with regard to sequence, and neutrality with regard to transference. In contrast to the rigid constraint on human responsiveness often caricatured in the literature, this vision of technical neutrality establishes its vital contribution to the integrity, depth, and tone of any analytic process that unfolds.

A thermolabile triosephosphate isomerase from the psychrophile Vibrio sp. strain ANT-300

We report the isolation of a gene encoding triosephosphate isomerase (TIM; EC 5.3.1.1) from Vibrio sp. strain ANT-300, a psychrophilic marine eubacterium that grows optimally at 7 degrees C. The deduced primary sequence of this isomerase is 50% identical to Escherichia coli TIM and 37% identical to the isomerase of the psychrotroph Moraxella sp. TA137. Transformation with this gene allowed growth of a TIM-deficient E. coli strain on selective media, but only at temperatures below 30 degrees C. The temperature dependence of this complementation is likely to result from an intrinsic thermolability of the isomerase. Indeed, the TIM activity present in ANT-300 lysates is markedly heat-sensitive, with a half-life of inactivation of 520 s at 25 degrees C.

A septic hip complicated by a ruptured appendix in an intravenous drug user

This paper reports on a case of hip joint sepsis complicated by a ruptured appendix in an intravenous drug user. A 41-year-old woman underwent open irrigation and débridement of her right hip joint for a methicillin-sensitive Staphylococcus aureus infection. Five days later the patient developed an intraperitoneal mass, requiring laparotomy and débridement of a periappendiceal abscess. The organisms infecting the abscess were different from those infecting the patient's hip. The patient recovered satisfactorily after 6 weeks of intravenous antibiotic therapy.

Phosphoglycerate kinase and triosephosphate isomerase from the hyperthermophilic bacterium Thermotoga maritima form a covalent bifunctional enzyme complex

Phosphoglycerate kinase (PGK) from the hyperthermophilic bacterium Thermotoga maritima has been purified to homogeneity. A second larger enzyme with PGK activity and identical N-terminal sequence was also found. Surprisingly, this enzyme displayed triosephosphate isomerase (TIM) activity. No other TIM is detectable in T. maritima crude extracts. As shown by ultracentrifugal analysis, PGK is a 43 kDa monomer, whereas the bifunctional PGK-TIM fusion protein is a homotetramer of 240-285 kDa. SDS-PAGE indicated a subunit size of 70 kDa for the fusion protein. Both enzymes show high thermostability. Measurements of the catalytic properties revealed no extraordinary results. pH optima, Km values and activation energies were found to be in the range observed for other PGKs and TIMs investigated so far. The corresponding pgk and tpi genes are part of the apparent gap operon of T. maritima. This gene segment contains two overlapping reading frames, where the 43 kDa PGK is encoded by the upstream open reading frame, the pgk gene. On the other hand, the 70 kDa PGK-TIM fusion protein is encoded jointly by the pgk gene and the overlapping downstream open reading frame of the tpi gene. A programmed frameshift may be responsible for this fusion. A comparison of the amino acid sequence of both the PGK and the TIM parts of the fusion protein with those of known PGKs and TIMs reveals high similarity to the corresponding enzymes from different procaryotic and eucaryotic organisms.

Stability of press-fit acetabular cups

Mechanical tests were performed to characterize the initial stability of press-fit cups as a function of cup design, surface structure, and surgical preparation. Eight cups from six manufacturers were press-fit into acetabular cavities prepared in two densities of Sawbones polyethylene foam and in bovine knee trabecular bone. Cavity sizes and cup loading forces were varied. Acetabular defects were simulated in the Sawbones model. Preparations were tested to determine axial-rotatory and tangential ("levering-out") stability. Results suggested that cup geometry and proper surgical technique--in particular, proper sizing and depth of the acetabular cavity--are important in determining initial cup stability independent of adjuvant screw or spike fixation. Stability is a function of the area of interface contact between the cup rim and the substrate. If the cavity is too small or too shallow, and the substrate too dense, the cup will not seat to the rim and stability will be compromised. If there are defects in the rim, the area of interface contact will be diminished and stability compromised. Cups with a true hemispherical design have a greater area of rim interface contact than "low-profile" cups and are therefore more stable. 1 mm undersizing of the cavity (or 2 mm undersizing in less dense substrate) appears to provide optimal stability.

On the dissociation constants of BAPTA-type calcium buffers

We have determined or redetermined the calcium dissociation constants of seven BAPTA-type buffers with KD's in the range from 0.4 microM to about 20 mM in 300 mM KCl. These include four newly synthesized ones: 5-nitro BAPTA; 5,5'-dinitro BAPTA; 5-methyl-5'-nitro BAPTA; and 5-methyl-5'-formyl BAPTA. Moreover, we tabulate dissociation constants or KD's for BAPTA and eleven BAPTA-type buffers, compare most of them with an empirical curve based upon so-called Hammett values, and predict KD's for several still unsynthesized but potentially valuable buffers.

Naso- and oropharyngeal dimensions in children with obstructive sleep apnea

Sixty children (3-11 years) were evaluated to determine variations in naso- and oropharyngeal dimensions associated with tonsil and adenoid hypertrophy. The subjects were grouped according to tonsil size and a clinical history of chronic upper airway obstruction. Intraoperative measurements included oropharyngeal diameter, length of the hard and soft palates, width and arch of the hard palate, nasopharyngeal volume, as well as tonsil and adenoid weights and volumes. A significantly larger oropharyngeal diameter was found in children with small, non-obstructing tonsils (P less than 0.01). Children with large, non-obstructing tonsils had a similar oropharyngeal diameter to those children with large, obstructing tonsils. However, tonsil volume, not weight, was increased in the children with large obstructing tonsils as compared to those with large non-obstructing tonsils and small non-obstructing tonsils (P less than 0.04). A shorter soft palate was associated with larger, obstructing tonsils (P less than 0.004). The length of the hard palate was similar in all patients, however, a trend towards a higher arched palate was seen in patients with larger, obstructing tonsils. The distance from the soft palate to the posterior pharyngeal wall was greater in obstructed patients with adenotonsillar hypertrophy (P less than 0.003). In patients requiring adenoidectomy, the nasopharyngeal volume prior to adenoidectomy was significantly smaller in patients with obstructive symptoms (P less than 0.001). Postadenoidectomy, no significant difference was found in the nasopharynx volume amongst all subjects. These data indicate that subtle differences in oropharyngeal dimensions exist which along with increased lymphoid tissue volume, lead to the development of obstructive symptoms. Etiologic considerations are discussed.