Using viral sequence diversity to estimate time of HIV infection in infants

Age at HIV acquisition may influence viral pathogenesis in infants, and yet infection timing (i.e. date of infection) is not always known. Adult studies have estimated infection timing using rates of HIV RNA diversification, however, it is unknown whether adult-trained models can provide accurate predictions when used for infants due to possible differences in viral dynamics. While rates of viral diversification have been well defined for adults, there are limited data characterizing these dynamics for infants. Here, we performed Illumina sequencing of gag and pol using longitudinal plasma samples from 22 Kenyan infants with well-characterized infection timing. We used these data to characterize viral diversity changes over time by designing an infant-trained Bayesian hierarchical regression model that predicts time since infection using viral diversity. We show that diversity accumulates with time for most infants (median rate within pol = 0.00079 diversity/month), and diversity accumulates much faster than in adults (compare previously-reported adult rate within pol = 0.00024 diversity/month [1]). We find that the infant rate of viral diversification varies by individual, gene region, and relative timing of infection, but not by set-point viral load or rate of CD4+ T cell decline. We compare the predictive performance of this infant-trained Bayesian hierarchical regression model with simple linear regression models trained using the same infant data, as well as existing adult-trained models [1]. Using an independent dataset from an additional 15 infants with frequent HIV testing to define infection timing, we demonstrate that infant-trained models more accurately estimate time since infection than existing adult-trained models. This work will be useful for timing HIV acquisition for infants with unknown infection timing and for refining our understanding of how viral diversity accumulates in infants, both of which may have broad implications for the future development of infant-specific therapeutic and preventive interventions.

Synthesis and aggregation behaviour of single-chain, 1,32-alkyl branched bis(phosphocholines): effect of lateral chain length

Three novel single-chain bis(phosphocholines) bearing two lateral alkyl chains of variable length next to the headgroup have been synthesized as model lipids for naturally occurring archaeal membrane lipids. The synthesis was realized using the Cu-catalyzed Grignard bis-coupling reaction of a primary bromide as a side part and a 1,ω-dibromide as a centre part. We could show that the aggregation behaviour of the resulting bolalipids strongly depends on the length of the lateral alkyl chain: the C3-branched bolalipid self-assembles into lamellar sheets, whereas the C6- and C9-analogues form nanofibres. The lamella-forming bolalipids could be used in the future to prepare stable and tailored liposomes for oral drug delivery.

Head Impact Exposure During a Weekend Youth Soccer Tournament

Concussion is a known risk in youth soccer, but little is known about subconcussive head impacts. The authors provided a prospective cohort study measuring frequency and magnitude of subconcussive head impacts using accelerometry in a middle school-age soccer tournament, and association between head impacts and changes in (1) symptoms, (2) cognitive testing, and (3) advanced neuroimaging. A total of 17 youth completed the study (41% female, mean 12.6 years). There were 73 head impacts >15g measured (45% headers) and only 2 had a maximum peak linear acceleration >50g No youth reported symptoms consistent with concussion. After correction for multiple comparisons and a sensitivity analysis excluding clear outliers, no significant associations were found between head impact exposure and neuropsychological testing or advanced neuroimaging. The authors conclude that head impacts were relatively uncommon and low in acceleration in youth playing a weekend soccer tournament. This study adds to the limited data regarding head impacts in youth soccer.

Agreement between High School Athletes and Their Parents on Reporting Athletic Events and Concussion Symptoms

An enhanced understanding of agreement levels between adolescents and parents for reporting athletic events and symptoms can help inform surveillance systems as well as clinical and epidemiological investigations of sports-related concussions. We sought to quantify agreement levels between high school athletes and parents for reporting: (1) number of games; (2) number of practices; (3) occurrence of an injury resulting in any concussion symptoms; and (4) presence of each specific symptom on the date of that injury among high school boys' football and girls' soccer athletes playing in Autumn 2012 in Washington State. There was substantial agreement on reporting the number of athletic events. Agreement levels were greater for games (kappa = 0.82; 95% confidence interval [CI]: 0.79-0.85 in boys' football; kappa = 0.75; 95% CI: 0.72-0.79 in girls' soccer) than for practices (kappa = 0.64; 95% CI: 0.62-0.67 in boys' football; kappa = 0.65; 95% CI: 0.62-0.67 in girls' soccer). There was moderate to substantial agreement on the occurrence of injury resulting in any concussion symptoms; however, agreement on the presence and severity of each symptom varied from poor to almost perfect. Overall, athletes reported greater severity of symptoms than parents did; notably, no difference in mean symptom scores was found when the athlete had a history of concussion. Agreement levels were greater when information was ascertained within 1 week of injury than when it was obtained later than 1 week. Including both athletes' and parents' reports of sports-related events and ascertaining information as soon as possible after injury are important considerations in designing injury surveillance systems.

Influence of rifampicin on the expression and function of human intestinal cytochrome P450 enzymes

AIMS

To investigate the potential induction by rifampicin of intestinal CYP2C8, CYP2C9, CYP2D6 and CYP3A4 using preparations of human enterocytes.

METHODS

Using a multilumen perfusion catheter shed human enterocytes were collected from 6 healthy subjects before and after 10 days of 600 mg day(-1) oral rifampicin administration. The protein expression of CYP2C8, CYP2C9, CYP2D6 and CYP3A4 as well as that of CYP3A4 mRNA was determined using Western blotting and RT-PCR, respectively.

RESULTS

CYP3A4 mRNA expression in shed enterocytes increased from 74.6 +/- 44.2 to 143.2 +/- 68.4 a.u. (P < 0.05, 95% CI: 21.8-115.3). Expression of CYP2C8 and CYP2C9 increased from 5.1 +/- 0.9 to 10.4 +/- 2.3 pmol mg(-1) protein (P < 0.01, 95% CI: 2.8-7.7) and from 4.2 +/- 1.4 to 5.7 +/- 1.1 pmol mg(-1) protein (P < 0.01, 95% CI: 0.6-2.4), respectively. No significant difference in CYP2D6 expression before and during rifampicin intake was observed. Rifampicin administration also resulted in a significant induction of CYP3A4 protein (34.1 +/- 10.7 vs. 113.9 +/- 31.1 pmol mg(-1) protein (P < 0.001, 95% CI: 51.8-107.6)). Ex vivo incubation of enterocyte homogenates with verapamil resulted in a significantly increased production of the metabolites formed via CYP3A4 (D-617: 125.9 +/- 118.8 vs. 277.2 +/- 145.5 pmol min(-1) mg(-1) protein (P < 0.05, 95% CI: 30.1-272.5); norverapamil: 113.0 +/- 57.9 vs. 398.4 +/- 148.2 pmol min(-1) mg(-1) protein (P < 0.05, 95% CI: 47.2-523.6)).

CONCLUSION

Our findings indicate that shed enterocytes are a useful tool to study the expression, regulation and function of drug metabolizing enzymes. Induction of intestinal CYP2C8 and CYP2C9 might contribute in part to rifampicin - mediated drug interactions, in addition to their hepatic counterparts and intestinal and hepatic CYP3A4.

The C3435T mutation in the human MDR1 gene is associated with altered efflux of the P-glycoprotein substrate rhodamine 123 from CD56+ natural killer cells

P-glycoprotein (PGP) is a membrane protein which determines drug disposition in humans (e.g. digoxin). It is also expressed in various leukocyte lineages with highest expression in CD56+ natural killer cells. Recently, a polymorphism in exon 26 (C3435T) of this gene was shown to correlate with intestinal PGP expression and function in humans. Carriers homozygous for this polymorphism (TT) showed more than two-fold lower PGP expression and higher digoxin plasma concentrations compared to the CC group. However, it is not known whether this mutation in the MDR1 gene is also associated with altered PGP function in peripheral blood cells. We therefore assessed efflux of the PGP-substrate rhodamine 123 from CD56+ natural killer cells. Leukocytes were isolated from whole blood of 10 CC, 10 CT and 11 TT healthy Caucasian individuals. Using flow cytometry, rhodamine fluorescence was determined in CD56+ cells. Moreover, MDRI mRNA was quantified in leukocytes by real-time polymerase chain reaction. Subjects with CC genotype revealed a significantly lower rhodamine fluorescence (i.e. higher PGP function) compared to individuals with TT genotype (51.1 +/- 11.4% versus 67.5 +/- 9.5%, p < 0.01). Heterozygous individuals had an intermediate rhodamine fluorescence (61.4 +/- 6.3%). MDR1 mRNA normalized for cyclophilin was lowest in the TT population (1.29 +/- 1.01), intermediate in heterozygous subjects (1.60 +/- 0.76) and highest in the CC group (1.91 +/- 0.94; not significant). In summary, subjects being homozygous for C in position 3435 of the MDR1 gene have a more pronounced efflux of rhodamine from CD56+ natural killer cells and a higher MDR1 mRNA expression in leukocytes than subjects with the TT genotype. Measurement of rhodamine efflux using flow-cytometry from peripheral blood cells allows assessment of genetically determined differences in P-glycoprotein function.

Disposition and pharmacologic effects of R/S-verapamil in patients with chronic atrial fibrillation: An investigation comparing single and multiple dosing

BACKGROUND

Racemic (R /S)- verapamil is widely used in the management of chronic atrial fibrillation. The negative dromotropic effect is mainly mediated by the S -enantiomer, which is preferentially metabolized. Previous studies report an accumulation of R /S- verapamil during long-term oral treatment of patients with chronic atrial fibrillation. However, the specific disposition of S -verapamil and the pharmacologic effects were not assessed. Therefore uncertainties about the need for dose adjustments remain.

METHODS

Using stable isotope technology and a stereospecific assay, we compared the pharmacokinetics and pharmacodynamics of intravenous (10 mg of d(7)-R /S -verapamil) and oral (240 mg of slow release (SR) d(0)-R /S -verapamil) R -verapamil and S -verapamil after the first dose (day 1) and after 3 weeks (day 21) of continuous oral therapy in 8 patients with long-term atrial fibrillation. On both study days, serum samples were obtained for the analysis of d(7)- and d(0)-R -verapamil and S -verapamil. Heart rate (HR) was monitored with electrocardiography (with each blood sample) and Holter electrocardiography (before the study, on day 1, and on day 21).

RESULTS

Compared with day 1, clearance of oral R -verapamil and S -verapamil was significantly reduced on day 21 (1007 +/- 380 versus 651 +/- 253 mL/min [-35%] and 5481 +/- 2731 versus 2855 +/- 1097 mL/min [-48%], respectively; P <.05), whereas only a moderate decrease was observed for intravenous R -verapamil and S -verapamil (-23% and -14%, respectively, not significant). Mean HR (89 +/- 11 bpm before verapamil) was effectively reduced, with the same effects on day 1 (68 +/- 8 bpm) and day 21 (68 +/- 8 bpm). Compared with day 1, the HR reduction per ng/mL of S -verapamil (calculated by the area under the curve [from 0-24 hours] ratio of HR reduction and S -verapamil concentration) was significantly lower on day 21 (0.7 +/- 0.4 versus 1.2 +/- 0.7 [bpm]. [ng/mL](-1), for day 21 versus day 1; P <.01).

CONCLUSIONS

In patients with chronic atrial fibrillation, clearance of oral, but not intravenous, S -verapamil and R -verapamil is significantly reduced with multiple doses compared with a single dose, thereby indicating predominant impairment of prehepatic rather than hepatic metabolism as the underlying mechanism. However, this kinetic change is clinically compensated by a decrease in the responsiveness to S -verapamil observed with regular dosing. The data suggest that despite accumulation of the drug individual verapamil doses can be maintained during long-term oral rate control therapy.

[Administration of adenosine for termination of atrioventricular nodal reentry tachycardia: induction of atrial fibrillation with rapid conduction over an accessory pathway and unmasking of concomitant Wolff-Parkinson-White syndrome]

The antiarrhythmic properties of adenosine, its ultra-short half-life and the absence of frequent serious side effects make it a front-line agent in arrhythmia management, especially in the treatment of atrioventricular nodal reentrant tachycardia. Due to a shortening of atrial refractoriness, adenosine can facilitate the induction of atrial fibrillation. Life threatening tachycardias may result from a potential rapid conduction of atrial fibrillation over an accessory pathway especially if the latter one has a short antegrade refractory period. We report a case of a 59 year old female patient in which intravenous administration of adenosine during typical atrioventricular nodal reentrant tachycardia was followed by atrial fibrillation with rapid conduction over a hitherto unknown accessory pathway. After intravenous administration of adenosine the tachycardia was terminated successfully within 38 s. After a short period of asystole, spontaneous atrial fibrillation developed unmasking an antegrade preexcitation with subsequent rapid ventricular response (210 b/min). The three-lead ECG showed a narrow QRS complex tachycardia. Because of spontaneous conversion to sinus rhythm and the absence of hemodynamic compromise there was no need for external cardioversion. During electrophysiological study an antidromic atrioventricular reentrant tachycardia was recorded over a left posteroseptal accessory pathway including antegrade conduction properties only. Because of its ultrashort half-life, serious side effects after adenosine administration are rare. The possibility of life threatening proarrhythmias after intravenous adenosine administration should be taken into consideration if the etiology of a paroxysmal supraventricular tachycardia is not clear and a concomitant Wolff-Parkinson-White syndrome cannot be excluded. As with application of all intravenous antiarrhythmic agents, the administration of adenosine should only be performed if continuous ECG monitoring and cardioversion facilities are available and possible.

[Rooming-in in psychiatry--treatment indications and implementation]

Basing on the concept of rooming-in as the joint hospitalisation of mentally ill mothers and their children, which was developed in gynaecology and paediatrics, the differential indication, setting variables and therapeutic strategies relevant for inpatient psychotherapy were described. Therefore, 15 cases treated in the Department of Psychiatry of the Medical University Luebeck were reviewed. It will be demonstrated that a differentiated treatment approach with mothers with severe non-psychotic disorders can be realised. The advantages of the rooming-in approach seem to be on the one hand more adequate possibilities in the diagnosis and treatment of problems of mother-child interaction involving the nursing group, and on the other hand the rooming-in approach allows to identify connections between specific biographical events and actual conflicts related to birth and bringing up of the children.

Rapid stimulation of type I 5'-deiodinase in rat pituitaries by 3,3',5-triiodo-L-thyronine

The negative feedback control of thyrotropin production by the anterior pituitary involves local 5'-deiodination of L-thyroxine (L-T4) to the active thyroid hormone 3,3',5-triiodo-L-thyronine (T3) by two 5'-deiodinase isozymes which are distinctly regulated by thyroid hormone. T3 rapidly increased steady-state mRNA levels and activity of type I iodothyronine-5'-deiodinase (5'DI) in rat anterior pituitary and in reaggregate cultures of anterior pituitaries. Type II 5'-deiodinase activity determined in parallel with 3,3',5-triiodo-L-thyronine (rT3) as substrate was markedly lower than that of 5'DI. 5'DI mRNA levels and activity were higher in anterior pituitaries of female compared to male rats. Neither gender differences nor T3 stimulation of 5'DI activity were found in the posterior part. These data demonstrate a T3 dependent expression of 5'DI in euthyroid anterior pituitary and suggest that this isozyme serves a major function within the complex network of thyroid hormone homeostasis.

Treatment of metastatic colorectal carcinoma with a combination of fluorouracil and recombinant interferon alfa-2b: preliminary data of a phase II study

From March 1990 to January 1991 52 previously untreated patients with metastatic colorectal carcinoma were enrolled in a phase II study with the combination of interferon alfa-2b and fluorouracil (5-FU). 5-FU 750 mg/m2 per day was administered as continuous infusion for 5 days, then weekly in a dose of 750 mg/m2 as IV push injection starting on day 15. Interferon alfa-2b (Intron A, ESSEX Pharma) 9 x 10(6) units was given subcutaneously three times per week. Response to therapy was evaluated after 3 and 6 months. So far, data on response rates and toxicity are available in 32 patients: partial remission, 10 patients (31%); stable disease, nine patients (28%); progressive disease, 12 patients (37%); toxic deaths, two patients (6%). Projected median survival has not been reached after 11 months. In about one third of the patients severe side effects occurred with leukopenia grade 3 and 4, diarrhea, mucositis and septic complications being the clinically most important. We think that this combination is an effective but toxic regimen in advanced colorectal carcinoma. Further studies must reevaluate both the schedule and the doses of the drugs administered.

Phase II trial of 5-fluorouracil and recombinant interferon alfa-2B in metastatic colorectal carcinoma

Between February 1990 and April 1991, 59 previously untreated patients with progressive and/or symptomatic metastatic colorectal carcinoma were enrolled in a phase II study of 5-fluorouracil (5-FU) and interferon alfa-2b (IFN-alpha). 5-FU 750 mg/m2/day was administered as continuous infusion for 5 days, then weekly in a dose of 750 mg/m2 as intravenous push injection starting on day 15. IFN-alpha 9 MU was given subcutaneously three times a week. Treatment was given for a maximum of 6 months. 55 patients are evaluable for response and 51 for toxicity. 17 patients (31%) achieved a partial remission, 15 (27%) had stable disease and 21 patients (38%) had progressive disease. Median duration of remission was 5 months and median survival for all patients 10 months. Toxicity was important with two treatment-related deaths and severe leukopenia, fever, diarrhoea and mucositis in about one third of the patients. In our opinion, this regimen is effective but rather toxic in metastatic colorectal carcinoma.

The effect of vasoactive intestinal polypeptide (VIP) on forskolin stimulated adenylate cyclase in the caudate-putamen of the rat

Vasoactive intestinal polypeptide (VIP) was incubated in an adenylate cyclase assay with a particulate fraction of caudate-putamen (CP) tissue of the rat in order to examine the effect of the peptide on forskolin-activated adenylate cyclase in vitro. Forskolin induced an enhancement of cyclic AMP formation that was mediated by an effect on catalytic subunit and stimulatory guanine nucleotide regulatory protein (Ns). In our preparation, VIP did not influence basal adenylate cyclase activity or the stimulation by dopamine and sodium fluoride but, in the absence of guanylylimidodiphosphate (guanosine 5'-(beta, y-imido)-triphosphate) VIP inhibited the forskolin-stimulation of the enzyme in a noncompetitive manner. Met-encephalin, acting on a D-2 receptor-coupled putative inhibitory guanine nucleotide regulatory protein (Ni), inhibited the adenylate cyclase activity stimulated by forskolin to a slightly greater extent than VIP. When assayed together, these inhibition effects were additive, implying that the peptide receptors are not identical. The Ni-antagonist, MnCl2 completely blocked the inhibition of met-encephalin but had no significant effect on VIP-induced inhibition. In addition, pertussis toxin did not influence the effect of VIP on forskolin-stimulation in contrast to cholera toxin which did antagonize the VIP effect via the stimulatory guanine nucleotide regulatory protein (Ns). Furthermore, specific D-1 and D-2 dopaminergic receptor antagonists alpha(+)-flupentixol and spiperone had no effect on VIP-modulated forskolin-stimulated adenylate cyclase activity. These results suggest that the neuromodulatory effect of VIP is mediated by a Ns distinct from those involved in several adenylate cyclase pools sensitive to stimulation by dopamine and VIP in the rat striatum.