Pentacarbonyl(4-phenylpyridine)tungsten(0) and pentacarbonyl(2-phenylpyridine)chromium(0)

In pentacarbonyl(4-phenylpyridine)tungsten(0), [W(C(11)H(9)N)(CO)(5)], the molecules have mm site symmetry and the pyridine ligand, with m symmetry, is completely planar. In pentacarbonyl(2-phenylpyridine)chromium(0), [Cr(C(11)H(9)N)(CO)(5)], the molecules are in general positions and the phenyl and pyridine rings of the ligand are twisted by 67.7 (3) degrees with respect to one another by rotation about the C-C bond joining them. In both compounds, the axial M-C(carbonyl) bond trans to the M-N(ligand) bond is significantly shorter than the equatorial M-C(carbonyl) bonds.

Light-dependent osmoregulation in pea stem protoplasts. photoreceptors, tissue specificity, ion relationships, and physiological implications

Light-induced changes in the volume of protoplasts bathed in a medium of constant osmolarity are useful indications of light-dependent cellular osmoregulation. With this in mind, we investigated the effect of light on the volume of protoplasts isolated from the elongating stems of pea (Pisum sativum) seedlings raised under red light. The protoplasts were isolated separately from epidermal peels and the remaining peeled stems. Under continuous red light, the protoplasts of peeled stems swelled steadily, but those of epidermal peels maintained a constant volume. Experiments employing far-red light and phytochrome-deficient mutants revealed that the observed swelling is a light-induced response mediated mainly by phytochromes A and B with a little greater contribution by phytochrome A. Protoplasts of epidermal peels and peeled stems shrank transiently in response to a pulse of blue light. The blue light responsiveness in this shrinking response, which itself is probably mediated by cryptochrome, is under the strict control of phytochromes A and B with equal contributions by these phytochromes. We suggest that the swelling response participates in the maintenance of high tissue tension of elongating stems and that the shrinking response is involved in stem growth inhibition. Other findings include the following: The swelling is caused by uptake of K+ and Cl-. The presence of Ca2+ in the bathing medium is required for phytochrome signaling in the swelling response, but not in the response establishing blue light responsiveness. Phytochrome A mediates the two responses in a totally red/far-red light reversible manner, as does phytochrome B.

Clustered mutations in HIV-1 gag are consistently required for escape from HLA-B27-restricted cytotoxic T lymphocyte responses

The immune response to HIV-1 in patients who carry human histocompatibility leukocyte antigen (HLA)-B27 is characterized by an immunodominant response to an epitope in p24 gag (amino acids 263-272, KRWIILGLNK). Substitution of lysine (K) or glycine (G) for arginine (R) at HIV-1 gag residue 264 (R264K and R264G) results in epitopes that bind to HLA-B27 poorly. We have detected a R264K mutation in four patients carrying HLA-B27. In three of these patients the mutation occurred late, coinciding with disease progression. In another it occurred within 1 yr of infection and was associated with a virus of syncytium-inducing phenotype. In each case, R264K was tightly associated with a leucine to methionine change at residue 268. After the loss of the cytotoxic T lymphocyte (CTL) response to this epitope and in the presence of high viral load, reversion to wild-type sequence was observed. In a fifth patient, a R264G mutation was detected when HIV-1 disease progressed. Its occurrence was associated with a glutamic acid to aspartic acid mutation at residue 260. Phylogenetic analyses indicated that these substitutions emerged under natural selection rather than by genetic drift or linkage. Outgrowth of CTL escape viruses required high viral loads and additional, possibly compensatory, mutations in the gag protein.

Pilot trial of interleukin-2 with granulocyte colony-stimulating factor for the mobilization of progenitor cells in advanced breast cancer patients undergoing high-dose chemotherapy: expansion of immune effectors within the stem-cell graft and post-stem-cell infusion

PURPOSE

To evaluate whether administration of interleukin-2 (IL-2) with granulocyte colony-stimulating factor (G-CSF) improves mobilization of immune effector cells into the stem-cell graft of patients undergoing high-dose chemotherapy and autografting.

PATIENTS AND METHODS

We performed a trial of stem-cell mobilization with IL-2 and G-CSF in advanced breast cancer patients receiving high-dose chemotherapy with cyclophosphamide, thiotepa, and carboplatin and stem cells followed by IL-2. The trial defined immune, hematologic, and clinical effects of IL-2 in this setting.

RESULTS

Of 32 patients enrolled, nine received G-CSF alone for mobilization. Twenty-one of 23 patients mobilized with IL-2 plus G-CSF had stem cells collected with more mononuclear cells than those receiving G-CSF (19.3 v 10.4 x 10(8)/kg; P =.006), but fewer CD34(+) progenitor cells (6.9 v 22.0 x 10(6)/kg; P =.049). The IL-2 plus G-CSF-mobilized patients had greater numbers of activated T (CD3(+)/CD25(+)) cells (P =.009), natural killer (NK; CD56(+)) cells (P =.007), and activated NK (CD56 bright(+)) cells (P: =.039) than those patients mobilized with G-CSF. NK (P =.042) and lymphokine-activated killer (LAK) (P =.016) activity was increased in those mobilized with IL-2 + G-CSF, whereas G-CSF-mobilized patients had a decline in cytolytic activity. In the third week posttransplantation, immune reconstitution was superior in those mobilized with IL-2 plus G-CSF based on greater numbers of activated T cells (P =.003), activated NK cells (P =.04), and greater LAK activity (P =.003). The 16 of 21 IL-2 + G-CSF-mobilized patients with adequate numbers of stem cells (> 1.5 x 10(6) CD34(+) cells/kg) collected engrafted rapidly posttransplantation.

CONCLUSION

The results demonstrate that G-CSF + IL-2 can enhance the number and function of antitumor effector cells in a mobilized autograft without impairing the hematologic engraftment, provided that CD34 cell counts are more than 1.5 x 10(6) cells/kg. Mobilization of CD34(+) stem cells does seem to be adversely affected. In those mobilized with IL-2 and G-CSF, post-stem-cell immune reconstitution of antitumor immune effector cells was enhanced.

Colored noise and computational inference in neurophysiological (fMRI) time series analysis: resampling methods in time and wavelet domains

Even in the absence of an experimental effect, functional magnetic resonance imaging (fMRI) time series generally demonstrate serial dependence. This colored noise or endogenous autocorrelation typically has disproportionate spectral power at low frequencies, i.e., its spectrum is (1/f)-like. Various pre-whitening and pre-coloring strategies have been proposed to make valid inference on standardised test statistics estimated by time series regression in this context of residually autocorrelated errors. Here we introduce a new method based on random permutation after orthogonal transformation of the observed time series to the wavelet domain. This scheme exploits the general whitening or decorrelating property of the discrete wavelet transform and is implemented using a Daubechies wavelet with four vanishing moments to ensure exchangeability of wavelet coefficients within each scale of decomposition. For (1/f)-like or fractal noises, e.g., realisations of fractional Brownian motion (fBm) parameterised by Hurst exponent 0 < H < 1, this resampling algorithm exactly preserves wavelet-based estimates of the second order stochastic properties of the (possibly nonstationary) time series. Performance of the method is assessed empirically using (1/f)-like noise simulated by multiple physical relaxation processes, and experimental fMRI data. Nominal type 1 error control in brain activation mapping is demonstrated by analysis of 13 images acquired under null or resting conditions. Compared to autoregressive pre-whitening methods for computational inference, a key advantage of wavelet resampling seems to be its robustness in activation mapping of experimental fMRI data acquired at 3 Tesla field strength. We conclude that wavelet resampling may be a generally useful method for inference on naturally complex time series.

Colored noise and computational inference in neurophysiological (fMRI) time series analysis: resampling methods in time and wavelet domains

Even in the absence of an experimental effect, functional magnetic resonance imaging (fMRI) time series generally demonstrate serial dependence. This colored noise or endogenous autocorrelation typically has disproportionate spectral power at low frequencies, i.e., its spectrum is (1/f)-like. Various pre-whitening and pre-coloring strategies have been proposed to make valid inference on standardised test statistics estimated by time series regression in this context of residually autocorrelated errors. Here we introduce a new method based on random permutation after orthogonal transformation of the observed time series to the wavelet domain. This scheme exploits the general whitening or decorrelating property of the discrete wavelet transform and is implemented using a Daubechies wavelet with four vanishing moments to ensure exchangeability of wavelet coefficients within each scale of decomposition. For (1/f)-like or fractal noises, e.g., realisations of fractional Brownian motion (fBm) parameterised by Hurst exponent 0 < H < 1, this resampling algorithm exactly preserves wavelet-based estimates of the second order stochastic properties of the (possibly nonstationary) time series. Performance of the method is assessed empirically using (1/f)-like noise simulated by multiple physical relaxation processes, and experimental fMRI data. Nominal type 1 error control in brain activation mapping is demonstrated by analysis of 13 images acquired under null or resting conditions. Compared to autoregressive pre-whitening methods for computational inference, a key advantage of wavelet resampling seems to be its robustness in activation mapping of experimental fMRI data acquired at 3 Tesla field strength. We conclude that wavelet resampling may be a generally useful method for inference on naturally complex time series.

Network 12 hepatitis B vaccination quality improvement program: an educational program directed at physicians, staff, and patients

Hepatitis B is easily spread via contact with infected blood. Hemodialysis patients and staff are particularly at risk for acquiring hepatitis B. Consequently, vaccination of hemodialysis patients and staff is strongly recommended. However, the vaccination rate among dialysis patients in this country remains below 50%. End-Stage Renal Disease (ESRD) Network 12 developed a quality improvement project directed at increasing patient vaccination by regular surveys, reports, and education of physicians, staff, and patients. Seventy-seven percent of facilities in the 4-state Network participated. Overall vaccination rate increased from 66.9% to 73.2% over 18 months (P <.05). The greatest improvement was seen among units with less than 60% of patients vaccinated initially, with mean facility vaccination rate increasing from 31.2 +/- 20.5% to 57.5 +/- 30.1% in the last available data period (P <.001). Only 3 of these 29 units failed to improve. The 90 units that had 60% to 97% vaccination rates initially improved significantly from 79.8 +/- 9.6% to 82.4 +/- 15% (P =.015). Three quarters of these units showed improvement. Only units with 100% vaccination deteriorated, but still maintained vaccination rates of 74.5 +/- 25.6%. An education-based quality improvement project can improve the hepatitis B vaccination rate of hemodialysis patients.

Granulocyte-colony stimulating factor (G-CSF) may improve disease outcome in elderly patients with diffuse large cell lymphoma (DLCL) treated with CHOP chemotherapy

Advanced age is an adverse prognostic factor in patients with DLCL. CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) has frequent dose-limiting toxicities, including myelosuppression. We retrospectively reviewed 50 consecutive patients > 60 years of age (median age 72) with B-cell DLCL who received CHOP with G-CSF. Patients received CHOP (median 6 cycles) at three-week intervals. G-CSF was given following all cycles of chemotherapy ("prophylactic G-CSF") in 28 of 50 patients, and following an episode of febrile neutropenia and thereafter in 19 patients, according to ASCO guidelines. Dose intensity, treatment delays, episodes of febrile neutropenia, complete response (CR) rate, disease-free survival, time-to-treatment failure, and overall survival were all analyzed according to the age-adjusted International Prognostic Index (aaIPI). The actual dose intensity for cyclophosphamide was 225.9 mg/m2/week and 0.90, respectively and for doxorubicin was 14.9 mg/m2/week (90% of ideal CHOP dosing for both drugs). Median followup was 4 years for the patients still living. Treatment delays and episodes of febrile neutropenia were less frequent among patients receiving G-CSF with all cycles of CHOP. The CR rates were 100%, 81%, 85%, and 36% for the low, low-intermediate, high-intermediate, and high aalPI risk groups, respectively. The 5-year actuarial relapse-free and overall survival for our patients were comparable to that of the cohort < or = 60 years of age and superior to the > 60 years of age cohort used to establish the aaIPI. With optimization of CHOP dosing, advanced age may not be an adverse prognostic factor for patients with DLCL. The routine use of G-CSF in elderly patients with DLCL should be further investigated.

Scoring written material from the Mini-Mental State Examination: a comparison of face-to-face, fax and video-linked scoring

We assessed the reliability of scoring written items of the Mini-Mental State Examination (MMSE) using different communication modes: face to face, fax and videoconferencing. A total of 99 MMSEs were recovered from the records of a community mental health team for the elderly. The written parts of the examination (sentence and pentagrams) were scored--in person, using a faxed copy or over the video-link--according to published criteria. Relative to in-person scoring, sentences could be scored reliably when faxed (kappa = 0.80), as could pentagrams (kappa = 0.71). Sentences could be reliably scored over the videoconferencing link (kappa = 0.70), but pentagrams could not (kappa = 0.47). Caution is required before accepting the results of scoring such tests over video-links.

Antibodies against ribosomal phosphoprotein P0 of Plasmodium falciparum protect mice against challenge with Plasmodium yoelii

Antibodies against the Plasmodium falciparum P0 ribosomal phosphoprotein (PfP0) have been detected exclusively but extensively in malaria-immune persons. Polyclonal rabbit and mice sera were raised against two recombinant polypeptides of P. falciparum P0 protein, PfP0N and PfP0C, covering amino acids 17 to 61 and the remaining amino acids 61 to 316, respectively. Sera against both these domains detected a 35-kDa protein from Plasmodium yoelii subsp. yoelii, a rodent malarial parasite, and stained the surface of merozoites in immunofluorescence assays. Total immunoglobulin G (IgG) purified from rabbit and mouse anti-PfP0 sera by ammonium sulfate and DEAE-cellulose chromatography was used for passive transfer experiments in mice. Mice passively immunized with both anti-PfP0N and anti-PfP0C showed distinctly lower levels of parasitemia than control mice. With immunizations on days -1, 0, 1, 3, and 5, about 50% of both sets of mice receiving anti-PfP0N and anti-PfP0C cleared the lethal 17XL strain of P. yoelii and revived by day 25. All the control mice died by day 10. By extending the immunization schedule, the survival period of the mice could be extended for every mouse that received anti-PfP0 IgG. These data demonstrate the cross-protection of the anti-PfP0 IgG and establish parasite P0 protein as a target for invasion-blocking antibodies.

[Determination of the adenosine triphosphate in myocardial tissue by ion-pair reversed-phase high performance liquid chromatography]

ATP depletion is an important factor contributing to the incomplete recovery of ventricular function following ischemia and reperfusion. A simple and rapid method for determination of adenosine triphosphate(ATP) in myocardial tissue by RP-HPLC was developed. The chromatographic conditions were as follows: Spherisorb ODS2 column, V(40 mmol/L KH2PO4 and 5 mmol/L TBAP):V(methanol) = 74:26 (pH 6.2) mobile phase and UV detector at 259 nm. The ATP in myocardium was extracted with 0.4 mol/L HClO4. The calibration curve showed a good linearity in 5 mg/L-100 mg/L(r = 0.9998). The recovery ranged from 97.8% to 104.1%. The limit of detection was 2 mg/L. The verified results demonstrated that this method is precise, accurate and can be used for determination of ATP in myocardial tissue.

Pentacarbonyl(di-2-pyridylamine)tungsten(0)

In the title molecular complex, (I), the W atom is in an octahedral environment with four equatorial carbonyl ligands and a fifth in an axial position trans to the monodentate dipyridylamine ligand. The long dimension of this last bisects the angle between two of the equatorial carbonyl groups and while the non-bonded pyridyl N atom is directed away from the W atom, the bridging amine group is directed towards it. Thus, in addition to the N atom to which it is attached, the amino H has two nearest neighbour C atoms of equatorial carbonyl groups but does not participate in hydrogen bonding in any real or usual sense. The W-C bond distance for the axial carbonyl group is notably less than those of the equatorial groups.

[A foci of Schistosomiasis mekongi rediscovered in Northeast Cambodia: cultural perception of the illness; description and clinical observation of 20 severe cases]

In 1992 a foci of Schistosomiasis mekongi was rediscovered in the province of Kracheh in Northeast Cambodia. Severe clinical signs due to portal hypertension, which were frequently observed in this population, allowed the discovery of this 'forgotten' focus. Elements of the perception of the population and clinical observations of 20 severe cases due to S. mekongi infections are presented. Interviews with patients and villagers of the area of Kracheh showed severe psychosocial impact including fear from death, infirmity and invalidity. The symptoms of schistosomiasis were well known by the population and were reported to have increased in frequency in the last two decades. They have received traditional names and specific traditional treatment. The description of the clinical cases illustrates the severe pathology, which was observed in the hospital of Sambour, in the north of the province of Kracheh. It shows the pathogenic potential of S. mekongi in all age groups (from 7 to 58 years old): cachexia, hepatosplenomegaly, stunting and retardation of puberty, decompensation of portal hypertension with ascites and rupture of oesophagual varicies. The efficacy of the treatment in the severe stages varies. A follow-up after 30 months showed that 5 patients died, 5 initially improved but then relapsed, 3 remained unchanged and only 5 patients clearly improved. Two patients could not be followed-up. The clinical observations and interviews show severe pathology with impact at both individual and community level. The infection with S. mekongi is the main factor but additional concomitant factors are responsible for this fact. At a certain stage of the disease the prognosis for successful treatment is very low. These observations show the importance of the foci in the Province of Kracheh, Cambodia and underline the need for a long-term global intervention.

Predicting deterioration in previously healthy infants hospitalized with respiratory syncytial virus infection

OBJECTIVE

To estimate the incidence of clinical deterioration leading to intensive care unit transfer in previously healthy infants with respiratory syncytial virus (RSV) infection hospitalized on a general pediatric unit and, to assess the hypothesis that history, physical examination, oximetry, and chest radiographic findings at time of presentation can accurately identify these infants.

STUDY DESIGN

A virology database was used to identify and determine the disposition of all children </=1 year of age admitted to the Children's Hospital at Strong (CHaS) with RSV infection during the 1985 to 1994 respiratory seasons. Index patients were all previously healthy, full-term infants admitted initially to the general inpatient services at CHaS or Rochester General Hospital, a second University of Rochester teaching hospital, whose clinical deterioration led to transfer to the pediatric intensive care unit (PICU). These infants were matched retrospectively (for year and date of infection, sex, chronologic age, and race) with two hospitalized controls who did not require PICU transfer. Chest radiographic findings, respiratory rate (RR), O(2) saturation, and presence of wheezing at time of presentation to the emergency department (ED) were compared.

RESULTS

During the study years, 542 previously healthy, full-term infants were admitted to the general pediatric unit at CHaS with proven RSV infection. Ten (1.8%; 95% confidence interval, 0.9%, 3.4%) were transferred subsequently to the PICU, primarily for close monitoring of progressive respiratory distress. Data for these patients and 7 patients transferred from Rochester General Hospital to the PICU at the CHaS were compared with those for control patients. The mean RR in the ED (63 vs 50), and O(2) saturation in the ED (88% vs 93%) were modestly abnormal in cases compared with controls. Wheezing on examination at time of presentation and chest radiographic findings did not differ between the two groups. A RR >80 and an O(2) saturation <85% at time of presentation each had a specificity >97% for predicting subsequent deterioration. Each parameter, however, had a sensitivity </=30%.

CONCLUSION

Clinical deterioration requiring PICU admission is an uncommon occurrence in previously healthy infants admitted to a general pediatric inpatient unit with RSV infection. Extreme tachypnea and hypoxemia were both associated with subsequent deterioration; however, only a small proportion of patients who clinically deteriorated presented in this way. The clinical usefulness of these parameters, therefore, is limited. respiratory syncytial virus, deterioration, healthy infants, prediction.

Correlation between histochemically assessed fiber type distribution and isomyosin and myosin heavy chain content in porcine skeletal muscles

Highly sensitive enzyme assays developed to differentiate skeletal muscle fibers allow the recognition of three main fiber types: slow-twitch oxidative (SO), fast-twitch oxidative glycolytic (FOG), and fast-twitch glycolytic (FG). Myosin, the predominant contractile protein in mammalian skeletal muscle, can be separated based on the electrophoretic mobility under nondissociating conditions into SM2, SM1, IM, FM3, and FM2 isoforms, or under dissociating conditions into myosin heavy chain (MHC) I, IIb, IIx/d, and IIa. The purpose of the present study was to determine whether the histochemical method of differentiation of fiber types is consistent with the electrophoretically identified isomyosin and MHC isoforms. These comparisons were made using serratus ventralis (SV), gluteus medius (GM), and longissimus muscles (LM) from 13 pigs. Two calculation methods for the histochemical assessed fiber type distribution were adopted. The first method incorporated the number of fibers counted for each fiber type and calculated a percentage of the total fiber number (fiber number percentage: FNP). The second method expressed the cross-sectional area of each fiber type as a percentage of the total fiber area measured per muscle (fiber area percentage: FAP). Independent of the calculation methods, correlation analyses revealed in all muscles a strong relation between SO fibers, the slow isomyosin (SM1 and SM2), and MHCI, as well as between the FG fibers, the fast isomyosin (FM3 and FM2), and MHCIIx/b content (P<.05). There were no correlations between FOG fiber population assessed by histochemical analysis and intermediate isoform (IM) or MHCIIa content. The present results did not provide conclusive evidence as to which of the calculation methods (FNP or FAP) was more closely related to myosin composition of skeletal muscles. Despite some incompatibility between the methods, the present study shows that histochemical as well as electrophoretic analyses yielded important information about the composition of porcine skeletal muscle. The combination of the two methods may be essential to accurately characterize porcine skeletal muscles.

The effects of different resistance training protocols on muscular strength and endurance development in children

BACKGROUND

Previous research has shown that children can increase their muscular strength and muscular endurance as a result of regular participation in a progressive resistance training program. However, the most effective exercise prescription regarding the number of repetitions remains questionable.

OBJECTIVE

To compare the effects of a low repetition-heavy load resistance training program and a high repetition-moderate load resistance training program on the development of muscular strength and muscular endurance in children. Design. Prospective, controlled trial.

SETTING

Community-based youth fitness center.

SUBJECTS

Eleven girls and 32 boys between the ages of 5.2 and 11.8 years.

INTERVENTION

In twice-weekly sessions of resistance training for 8 weeks, children performed 1 set of 6 to 8 repetitions with a heavy load (n = 15) or 1 set of 13 to 15 repetitions with a moderate load (n = 16) on child-size exercise machines. Children in the control group (n = 12) did not resistance train. One repetition maximum (RM) strength and muscular endurance (repetitions performed posttraining with the pretraining 1-RM load) were determined on the leg extension and chest press exercises.

RESULTS

One RM leg extension strength significantly increased in both exercise groups compared with that in the control subjects. Increases of 31.0% and 40.9%, respectively, for the low repetition-heavy load and high repetition-moderate load groups were observed. Leg extension muscular endurance significantly increased in both exercise groups compared with that in the control subjects, although gains resulting from high repetition-moderate load training (13.1 +/- 6.2 repetitions) were significantly greater than those resulting from low repetition-heavy load training (8.7 +/- 2.9 repetitions). On the chest press exercise, only the high repetition-moderate load exercise group made gains in 1-RM strength (16.3%) and muscular endurance (5.2 +/- 3.6 repetitions) that were significantly greater than gains in the control subjects.

CONCLUSION

These findings support the concept that muscular strength and muscular endurance can be improved during the childhood years and favor the prescription of higher repetition-moderate load resistance training programs during the initial adaptation period.

The effect of external Ca2+ and Ca(2+)-channel modulators on red-light-induced swelling of protoplasts of Phaseolus radiatus L

Red-light-induced swelling of the protoplasts isolated from hypocotyl of etiolated mung bean (Phaseolus radiatus L.) was observed only when Ca2+ ions were present in the medium. The optimal CaCl2 concentration was 250 microM. Swelling response declined when Ca2+ was supplied into the medium after red light irradiation. The Ca(2+)-chelator EGTA eliminated the red-light-induced swelling and 45Ca2+ accumulation in the protoplasts. In contrast, A23187, a Ca(2+)-ionophore, could mimic the effect of red light in darkness. These results indicate that Ca2+ may play a role in light signal transduction. In addition, swelling response was prevented by TFP and CPZ (both are CaM antagonists), implying the involvement of CaM in red-light-induced and Ca(2+)-dependent protoplast swelling.

Persistence of human herpesvirus 6 according to site and variant: possible greater neurotropism of variant A

Little is known of the persistence and pathogenicity of human herpesvirus 6 (HHV-6) after primary infection, including the role of strain variant. Over 2 to 5 years, 2,716 children and 149 families were studied. Peripheral blood mononuclear cell (PBMC), saliva, and cerebrospinal fluid (CSF) specimens were examined for HHV-6 DNA and variant. Ninety-nine percent of isolates causing primary infection were HHV-6 variant B (HHV-6B), which predominated in 95%-98% of the variants persisting in PBMC and saliva specimens from children and adults. Of 668 CSF samples, 13% contained HHV-6 DNA; of 77 children examined after primary infection, 61% had HHV-6 DNA detected only in their CSF and 39% had HHV-6 DNA in both CSF and PBMCs. HHV-6 variant A (HHV-6A) was detected significantly (P = .0001) more frequently in CSF than in PBMCs or saliva. In children for whom HHV-6 was identified in both CSF and PBMCs, PBMCs contained only HHV-6B, while CSF contained HHV-6A or HHV-6B, not both. Thus, in patients with dual infection, only HHV-6A persisted in CSF, which suggests that HHV-6A has greater neurotropism. Findings for adults indicate that dual infection occurs; variant persistence is similar to that for children. The frequency of HHV-6A infection increased little with age, thereby indicating that HHV-6A infection remains uncommon into adulthood. This study suggests that HHV-6 variants have different immunobiologic courses and neurotropism.

[Quantitative determination of niphensamide by high performance liquid chromatography (HPLC)]

An HPLC method for the quantitative determination of Niphensamide in pesticide powder was developed. Column:Micropak-CH 5 microns (300 mm x 4.0 mm i.d.), mobile phase: CH3OH-H2O(1:1), detector: UV 254 nm, flow rate: 0.7 mL/min, column temperature: 25 degrees C. Under the above conditions, Niphensamide and other components were separated from each other. The method is simple, rapid, sensitive and accurate.