Clinical trial: intra dermal hepatitis B vaccination with topical imiquimod versus intra muscular hepatitis B vaccination in patients with inflammatory bowel disease

BACKGROUND

Efficacy with conventional intra muscular (IM) hepatitis B vaccination in patients with inflammatory bowel disease (IBD) is suboptimal.

AIM

To compare the immunogenicity of intradermal (ID) hepatitis B vaccination after topical imiquimod pre-treatment with IM hepatitis B vaccination in patients with IBD.

METHODS

Adult IBD patients with no evidence of hepatitis B infection or immunity (negative to HBsAg/anti-HBc/anti-HBs) were randomised 1:1 to receive either ID hepatitis B vaccine with topical imiquimod pre-treatment to injection site (ID-Imq) or IM hepatitis B vaccine with aqueous cream pre-treatment (IM-Aq) at 0, 1 and 6 months. Patients and investigators were blinded to the randomisation and intervention. The primary endpoint was seroprotection rate at 12-month, defined as percentage of subjects with anti-HBs ≥10 mIU/ml.

RESULTS

Between September 2019 and December 2020, 104 patients with IBD (68% male; 50% Crohn's) enrolled, and 53 assigned to ID-Imq group. The percentage of patients using steroids, immunomodulators or biologics at randomisation was 15%, 55% or 22%, respectively. Seroprotection rate at 12 months was significantly higher in the ID-Imq group than the IM-Aq group (91% vs 69%; OR 4.39, 95% CI 1.47-13.11). Multivariate analysis showed that ID vaccine with topical imiquimod and higher albumin level were associated with a higher seroprotection rate. The safety profile was similar but local reactions were more common in the ID-Imq group.

CONCLUSIONS

Intradermal hepatitis B vaccination with topical imiquimod pre-treatment is safe and offers superior seroprotection to conventional IM administration in patients with IBD.

Tree-in-Bud Opacities: Not only tuberculosis

We report a clinical case of mentally challenged young gentleman who was repeatedly hospitalized for respiratory symptoms. Contrast-enhanced CT (computed tomography) thorax revealed tree-in-bud (TIB) opacities. Provisional diagnosis of pulmonary tuberculosis was made and was referred to the respiratory team. However, after listening to patient's voice and reviewing the images on CT thorax, the diagnosis was confirmed as aspiration bronchiolitis.

Role of serum HBV RNA and hepatitis B surface antigen levels in identifying Asian patients with chronic hepatitis B suitable for entecavir cessation

BACKGROUND

Treatment cessation in chronic HBV infection may be durable in certain patient subgroups before hepatitis B surface antigen (HBsAg) seroclearance. The role of serum HBV RNA in determining treatment cessation suitability has not been well-investigated.

METHODS

Nucleos(t)ide analogue (NUC) treatment was discontinued in non-cirrhotic patients with chronic HBV with serum HBsAg <200 IU/mL and fulfilling internationally recommended criteria for treatment cessation. Patients were monitored till 48 weeks with baseline and serial measurements of serum HBsAg, HBV RNA and hepatitis B core-related antigen. NUCs were resumed when HBV DNA reaches >2000 IU/mL regardless of alanine aminotransferase (ALT) levels.

RESULTS

114 entecavir-treated patients (median age 58.4 years, median serum HBsAg 54.4 IU/mL) with median treatment duration of 6.7 years were recruited. The 48-week cumulative rate of HBV DNA >2000 IU/mL was 58.1%. End-of-treatment serum HBV RNA and off-treatment serial HBV RNA were both independently associated with HBV DNA >2000 IU/mL (HR 2.959, 95% CI 1.776 to 4.926, p<0.001; HR 2.278, 95% CI 1.151 to 4.525, p=0.018, respectively). Patients with HBV RNA ≥44.6 U/mL had a cumulative 48-week rate of 93.2%, while combining HBV RNA undetectability and HBsAg <10 IU/mL had a cumulative 48-week rate of 9.1%. 24 patients (38.7%) developed off-treatment ALT elevation, highest peak ALT was 1515 U/L. 8 patients (median serum HBsAg 2.6 IU/mL) developed HBsAg seroclearance.

CONCLUSION

Serum HBV RNA measurement is essential for deciding on entecavir cessation in patients with chronic HBV, especially with low HBsAg levels. Patients can be stratified on their risk of off-treatment relapse based on both viral determinants.

TRIAL REGISTRATION NUMBER

NCT02738554.

Personalised management of Chronic Obstructive Pulmonary Disease (COPD): Malaysian consensus algorithm for appropriate use of inhaled corticosteroid (ICS) in COPD patients

BACKGROUND

Regarding the long-term safety issues with the use of inhaled corticosteroids (ICS) and the clinical predominance of dual bronchodilators in enhancing treatment outcomes in chronic obstructive pulmonary disease (COPD), ICS is no longer a "preferred therapy" according to the Global Initiative for Chronic Obstructive Lung Disease except on top of a dual bronchodilator. This has necessitated a change in the current therapy for many COPD patients.

OBJECTIVE

To determine a standardised algorithm to reassess and personalise the treatment COPD patients based on the available evidence.

METHODS

A consensus statement was agreed upon by a panel of pulmonologists in from 11 institutes in Malaysia whose members formed this consensus group.

RESULTS

According to the consensus, which was unanimously adopted, all COPD patients who are currently receiving an ICS-based treatment should be reassessed based on the presence of co-existence of asthma or high eosinophil counts and frequency of moderate or severe exacerbations in the previous 12 months. When that the patients meet any of the aforementioned criteria, then the patient can continue taking ICS-based therapy. However, if the patients do not meet the criteria, then the treatment of patients need to be personalised based on whether the patient is currently receiving long-acting beta-agonists (LABA)/ICS or triple therapy.

CONCLUSION

A flowchart of the consensus providing a guidance to Malaysian clinicians was elucidated based on evidences and international guidelines that identifies the right patients who should receive inhaled corticosteroids and enable to switch non ICS based therapies in patients less likely to benefit from such treatments.

A Territorywide Prevalence Study on Blood-Borne and Enteric Viral Hepatitis in Hong Kong

BACKGROUND

Viral hepatitis epidemiological data are important for the World Health Organization plan of eliminating viral hepatitis. We aimed to document the prevalence of viral hepatitis A to E in Hong Kong.

METHODS

This community-based study was open to all Hong Kong Chinese citizens aged ≥18 years. Baseline data and risk factors were collected. Hepatitis A-E serology was measured, including hepatitis B e antigen, antibodies to hepatitis B e antigen, antibodies to hepatitis D, hepatitis B virus (HBV) DNA for hepatitis B surface antigen (HBsAg)-positive participants, and antibodies to hepatitis B surface antigen and antibodies to hepatitis B core antigen (anti-HBc) in HBsAg-negative participants. Hepatitis C virus (HCV) RNA and genotypes were determined in anti-HCV-positive participants.

RESULTS

A total of 10 256 participants were recruited from February 2015 to July 2016. Overall HBsAg seroprevalence was 7.8% (95% confidence interval [CI], 7.3%-8.3%), which was reduced significantly with HBV vaccination (odds ratio, 0.15 [95% CI, .11-.21]). Among HBsAg-negative participants, anti-HBc seroprevalence increased from 5.4% (<26 years) to 60.1% (>65 years). No hepatitis D virus (HDV) cases were detected. Anti-HCV positivity was 0.5% (95% CI, .3%-.6%). Prevalence of antibodies to hepatitis A virus (anti-HAV) and hepatitis E virus (anti-HEV) was 65.2% (95% CI, 64.2%-66.1%) and 33.3% (95% CI, 32.4%-34.2%), respectively, and were influenced by age, family income, and being born in mainland China.

CONCLUSIONS

HBV seroprevalence remained high despite universal vaccination. High anti-HBc seroprevalence underlines the potential issue of HBV reactivation during profound immunosuppression. HCV and HDV remained uncommon. Anti-HAV seroprevalence had decreased whereas anti-HEV seroprevalence had risen.

Seven-Year Treatment Outcome of Entecavir in a Real-World Cohort: Effects on Clinical Parameters, HBsAg and HBcrAg Levels

Objectives:

We aimed to determine the levels of alanine aminotransferase (ALT), hepatitis B virus DNA (HBV DNA), HBsAg, and a novel viral marker (hepatitis B core-related antigen (HBcrAg)); hepatitis B e antigen (HBeAg) seroconversion and drug resistance rates after 7 years of entecavir treatment in chronic hepatitis B (CHB) patients.

Methods:

Two hundred and twenty-two Chinese CHB patients on continuous entecavir treatment were recruited. Serologic, virologic, biochemical outcomes, and the occurrence of entecavir signature mutations were determined.

Results:

The rates of ALT normalization, HBeAg seroconversion, and undetectable HBV DNA were 98.3%, 82.1%, and 98.7%, respectively, after 7 years of entecavir treatment. The genotypic resistance rate was 1.2%. Decline of HBsAg level was modest with a median decline rate of 0.107 log IU/ml/year. Among patients with baseline HBsAg <1,000 IU/ml and annual HBsAg decline rate of ≥0.166 log IU/ml, all have HBsAg of <200 IU/ml (a level highly predictive for HBsAg seroclearance) at year 7. In contrast, in patients with baseline HBsAg ≥1,000 IU/ml and annual HBsAg decline rate of <0.166 log IU/ml, 95.5% had HBsAg of ≥200 IU/ml at year 7. Decline of HBcrAg levels was moderate with a median decline rate of 0.244 log kU/ml/year. Forty-seven patients (32.0%) had undetectable HBcrAg level at year 7.

Conclusions:

Long-term entecavir therapy continued to have good responses with low drug resistance rate. However, the decline of HBsAg with treatment was suboptimal. HBcrAg level declined at a relatively better rate. Baseline HBsAg level of <1,000 IU/ml and annual decline of 0.166 log IU/ml could be used to predict HBsAg response.

Hepatitis B reactivation in occult viral carriers undergoing hematopoietic stem cell transplantation: A prospective study

Hepatitis B virus (HBV) reactivation in hepatitis B surface antigen (HBsAg)-negative, antibody to hepatitis B core antigen (anti-HBc)-positive patients after allogeneic hematopoietic stem cell transplantation (HSCT) has not been prospectively studied. HBsAg-negative, anti-HBc-positive patients with undetectable HBV DNA undergoing allogeneic HSCT were prospectively monitored every 4 weeks. The primary endpoint was HBV reactivation, defined as detectable HBV DNA (≥10 IU/mL). Secondary endpoints included overall survival, HBsAg positivity, and changes in liver biochemistry and antibody to HBsAg levels. Among 297 allogeneic HSCT recipients, 85 (28.7%) were HBsAg-negative, anti-HBc-positive, of whom 62 were recruited and monitored for a median of 48 (4-104) weeks. The 2-year cumulative HBV DNA detectability rate was 40.8%, occurring at a median of 44 (8-100) weeks. Multivariate analysis showed that age ≥50 years (P = 0.004, hazard ratio = 8.2) and chronic graft-versus-host disease (P = 0.010, hazard ratio = 5.3) were significantly associated with HBV reactivation. Other clinical parameters, including baseline antibody to HBsAg status, serial changes in antibody to HBsAg levels, and donor serology, were not associated with HBV reactivation. Patients <50 years old and without chronic graft-versus-host disease, compared with the remaining patient cohort, had a significantly lower 2-year cumulative HBV reactivation rate (5.6% versus 65.0%, P = 0.004). Entecavir successfully suppressed HBV DNA to undetectable levels, with no cases developing biochemical hepatitis.

CONCLUSION

HBsAg-negative, anti-HBc-positive patients had a high rate of HBV reactivation after allogeneic HSCT, with determinants of HBV reactivation including age ≥50 years and chronic graft-versus-host disease; treatment strategies based on these parameters may prevent HBV reactivation and subsequent complications. (ClinicalTrials.gov identifier NCT01481649.) (Hepatology 2017;65:1451-1461).

A review of the clinical approach to persistent pain following total hip replacement

Total hip arthroplasty is effective in reducing pain and improving functional outcome for a variety of hip pathologies. Approximately 27% patients, however, complain of pain at 6 months' follow-up following surgery. The pain may worsen over time and can become severe and chronic in around 4% of patients who ultimately require revision surgery. Therefore, it is important for clinicians to comprehensively assess patients undergoing total hip arthroplasty in order to identify the underlying pathology of a painful hip and then offer prompt treatment. Causes of hip pain after total hip arthroplasty are analysed in this article, as well as the systematic approach to evaluation and appropriate diagnostic investigations.

Hepatitis B reactivation in patients with previous hepatitis B virus exposure undergoing rituximab-containing chemotherapy for lymphoma: a prospective study

PURPOSE

Patterns of hepatitis B virus (HBV) reactivation in hepatitis B surface antigen (HBsAg) -negative, antihepatitis B core antigen antibody (anti-HBc) -positive patients with lymphoma receiving rituximab-containing chemotherapy have not been well described.

PATIENTS AND METHODS

HBsAg-negative, anti-HBc-positive Chinese patients with undetectable serum HBV DNA (< 10 IU/mL), diagnosed with hematologic malignancies and receiving rituximab-containing chemotherapy, were prospectively monitored every 4 weeks for up to 2 years. Entecavir was started when HBV reactivation (defined as detectable HBV DNA) was encountered.

RESULTS

Among 260 patients receiving rituximab-containing chemotherapy, 63 patients (24.2%) who were HBsAg negative and anti-HBc positive underwent follow-up for a median of 70 weeks (range, 6 to 104 weeks). The 2-year cumulative rate of HBV reactivation was 41.5%, occurring at a median of 23 weeks (range, 4 to 100 weeks) after rituximab treatment. The median HBV DNA level at reactivation was 43 IU/mL (range, 14 to 920 IU/mL). A baseline undetectable antibody to HBsAg (anti-HBs; < 10 mIU/mL) was the only significant risk factor that was positively associated with HBV reactivation (hazard ratio, 3.51; 95% CI, 1.37 to 8.98; P = .009). Patients with negative baseline anti-HBs, compared with those with positive anti-HBs, had a significantly higher 2-year cumulative rate of HBV reactivation (68.3% v 34.4%; P = .012). At HBV reactivation, all patients had normal ALT, and all patients but one were HBsAg negative. Entecavir successfully controlled HBV reactivation in all patients.

CONCLUSION

A high rate of HBV reactivation was observed in HBsAg-negative, anti-HBc-positive patients undergoing rituximab-containing chemotherapy, with the risk of reactivation significantly higher in anti-HBs-negative patients. Periodic HBV DNA monitoring was an effective strategy in preventing HBV-related complications.

Refeeding syndrome: the danger of feeding a starving man

Refeeding syndrome is a potentially fatal clinical condition characterized by severe electrolyte and fluid shifts associated with metabolic abnormalities in severely malnourished or starved patients undergoing oral, enteral or parenteral refeeding. We here present a case of a 50-year-old Indian male with a background of depression and alcoholic liver disease presented with alleged ingestion of a detergent. He subsequently developed an oesophageal stricture resulting in severe malnutrition. He developed refeeding syndrome following commencement of TPN associated with clear biochemical alteration. This was immediately identified and rectified. This case report highlights the prevalence of refeeding syndrome in a typical hospital setting that can easily be overlooked and stresses the importance of early recognition as this is a preventable disorder.

Changes of HBsAg and HBV DNA levels in Chinese chronic hepatitis B patients after 5 years of entecavir treatment

BACKGROUND AND AIM

Hepatitis B surface antigen (HBsAg) kinetics during long-term entecavir therapy has not been well investigated.

METHODS

We described the cumulative serologic, virologic, and biochemical outcomes and the occurrence of signature entecavir mutations among 222 Chinese treatment-naïve chronic hepatitis B (CHB) patients receiving entecavir for up to 5 years.

RESULTS

The median rate of HBsAg reduction over 5 years was 0.125 log IU/mL/year. Patients with high baseline HBV DNA levels (≥ 8 log copies/mL or ≥ 7.3 log IU/mL), when compared with those with baseline hepatitis B virus (HBV) DNA < 7.3 log IU/mL, had a significantly greater median rate of HBsAg reduction (0.178 and 0.102 log IU/mL/year, respectively, P < 0.001). The difference in HBsAg decline was most prominent in the first year (0.324 and 0.062 log IU/mL/year, respectively, P < 0.001). Greater median rates of HBsAg reduction were also found in hepatitis B e antigen (HBeAg)-positive patients when compared with HBeAg-negative patients (0.144 and 0.098 log IU/mL/year, P = 0.015), and in patients with high baseline HBsAg levels (≥ 3 log IU/mL), when compared with patients with low baseline HBsAg < 3 log IU/mL (0.131 and 0.045 log IU/mL/year, respectively, P = 0.001). The 5-year cumulative rate of HBV DNA undetectability (< 20 IU/mL) was 97.1%. There were two cases of entecavir resistance, resulting in a 5-year cumulative resistance rate of 1.2%.

CONCLUSION

In contrast to the profound HBV DNA suppression, long-term entecavir treatment achieved only a slow decline in serum HBsAg. Although certain patient subgroups exhibit a more rapid HBsAg reduction, additional therapeutic agents are needed to increase the chance of HBsAg seroclearance in CHB.

HLA-DP and γ-interferon receptor-2 gene variants and their association with viral hepatitis activity in chronic hepatitis B infection

BACKGROUND AND AIM

Studies show that polymorphisms in human leukocyte antigen (HLA)-DP loci and certain γ-interferon (IFN-γ) signaling pathway genes are related to persistence of hepatitis B virus (HBV) infection and viral load in chronic HBV (CHB) infection respectively. Our study aims to determine whether single-nucleotide polymorphisms (SNPs) linked to HLA-DP loci and IFN-γ signaling pathway are associated with HBV activities.

METHODS

We compared the SNPs in the HLA-DPA1 gene (rs3077) and the IFN-γ receptor-2 gene (rs2284553 and rs9808753) of 100 treatment-naive hepatitis B e antigen (HBeAg)-negative CHB patients with undetectable HBV DNA with 100 age- and sex-matched controls with HBV DNA > 2000 IU/mL.

RESULTS

The median age of the study group was 47.9 years, and 61% were male patients. The distribution of the three polymorphisms was in Hardy-Weinberg equilibrium. Both rs3077 and rs2284553 polymorphisms were not associated with HBV viral load in terms of allelic frequency, genotypic frequency, dominant/recessive gene action. rs9808753 (G allele) was associated with a reduced chance of "undetectable HBV DNA" for patients below the age of 50 years in allelic frequency analysis (odds ratio 0.562; 95% confidence interval, 0.326-0.967; P value = 0.037). IFN-γ receptor-2 gene haplotype block (rs2284553/rs9808753) was not associated with HBV viral activity.

CONCLUSION

There was no significant association between HLA-DP polymorphism (rs3077) and IFN-γ receptor-2 gene polymorphism (rs2284553) with viral activity in HBeAg-negative CHB patients. Further studies are required to confirm the association between IFN-γ receptor-2 gene polymorphism (rs9808753) and reduced chance of having "undetectable HBV DNA" in young CHB patients.

Current Antiviral Therapy of Chronic Hepatitis B: Efficacy and Safety

The treatment of chronic hepatitis B is in constant evolution. Interferon, the first agent licensed for chronic hepatitis B treatment, has been superseded by the growing popularity of nucleoside/nucleotide analogues (NA). However, resistance to these agents is a major challenge. Newer NAs, such as entecavir and tenofovir dipivoxil fumarate, have very low resistance rates and favorable safety profiles. Long-term use of these agents can effectively suppress hepatitis B virus DNA, leading to decrease in incidence of hepatitic flares, as well as in the development of cirrhosis and hepatocellular carcinoma. The efficacy and safety of various antiviral agents is discussed in this review.

One-step convergent synthesis of the steroid ring system via the coupling of gamma,delta-unsaturated Fischer carbene complexes with o-ethynylbenzaldehyde

[reaction: see text]. Simultaneous and stereoselective construction of the steroid B and C rings is observed in a tandem process involving the coupling of o-ethynylbenzaldehyde with 2-alkenylcyclopentylcarbene-chromium complexes.

2'-Deoxyguanosine reacts with a model quinone methide at multiple sites

Quinone methides and related intermediates have been implicated in a range of beneficial and detrimental processes in biology and effectively alkylate a variety of cellular components despite the ubiquitous presence of water. As a prerequisite to understanding the origins of their specificity, the major products generated by DNA and its components with an unsubstituted ortho quinone methide under aqueous conditions were recently characterized [Pande, P., Shearer, J., Yang, J., Greenberg, W. A., and Rokita, S. E. (1999) J. Am. Chem. Soc. 121, 6773-6779]. Investigations currently focus on the complete range of derivatives formed by deoxyguanosine (dG) and guanine residues in duplex DNA through product isolation and structure determination using reversed-phase chromatography and a range of one and two-dimensional NMR techniques. Previous construction of a synthetic standard for dG alkylation is now shown to have yielded the N1-linked adduct rather than the N(2)-linked adduct. This later adduct has also now been characterized and confirmed to be the major product of reaction between the quinone methide and both duplex DNA and dG under neutral conditions. An N7 adduct of guanine has additionally been identified under these conditions and appears to result from spontaneous deglycosylation of the corresponding N7 adduct of dG. A combination of steric and electronic properties of duplex DNA likely contribute to the enhanced selectivity of the quinone methide for its guanine N(2) position (7.8:3.2:1.0 for adducts of N(2):N7:N1) relative to that of dG (4.7:3.5:1.0 for adducts of N(2):N7:N1).

Atranones A-G, from the toxigenic mold Stachybotrys chartarum

Atranones A-G have been isolated from the toxigenic fungus Stachybotrys chartarum. These compounds contain several unusual features including an enol-lactone as part of a 3,7-dioxabicyclo[3.3.0]octane-2-one ring system fused to an 11-membered ring. Two new dolabellane diterpenes, related in structure to the atranones were also isolated, which suggests a diterpenoid origin for the C24 atranones.

Guest and subunit exchange in self-assembled ionophores

[reaction: see text] Self-assembled ionophores, formed by hydrogen bonding of isoG 1 around a cation, are dynamic structures. Multinuclear NMR spectroscopy in CD(3)CN-CDCl(3) showed that cation exchange is >10(4) faster than exchange of isoG 1 ligand in (isoG 1)(10)-Cs(+) Ph(4)B(-). The cationic guest also affected the kinetic stability of the complex. 2D-EXSY NMR experiments in CDCl(3) showed that ligand exchange was 2 orders of magnitude faster for the Li(+)-decamer than for the Cs(+)-decamer.

Homodimeric and heterodimeric aryl sulfotransferases catalyze the sulfuric acid esterification of N-hydroxy-2-acetylaminofluorene

Three aryl sulfotransferases (ASTs) isolated from rat liver catalyze the sulfuric acid esterification of the carcinogen N-hydroxy-2-acetylaminofluorene (N-OH-2AAF). These three ASTs were separated by high resolution anion exchange chromatography and were designated Q1, Q2, and Q3. Q1 and Q2 had high N-OH-2AAF sulfonation activity, whereas Q3 showed low activity. Reversed phase high performance liquid chromatography/mass spectrometry analysis showed Q1-Q3 to be comprised of 33,945- and 35,675-Da protein subunits. Q1 contained only the 35,675-Da protein subunit, Q2 contained equal quantities of 33,945- and 35,675-Da subunits, and Q3 contained only the 33,945-Da subunit. The subunit compositions of Q1-Q3 were confirmed by immunochemical analysis. Size exclusion high performance liquid chromatography confirmed that the active quaternary structure of the three isoenzymes was dimeric. Analysis of liver cytosols for the relative contributions of Q1-Q3 to total cytosolic N-OH-2AAF sulfotransferase activity indicated the Q1, Q2, and Q3 accounted for 44, 46, and 10% of the activity, respectively. These results demonstrate the existence of both homodimeric and heterodimeric aryl sulfotransferases and show that two ASTs, a homodimer of 35,675-Da subunits and a heterodimer of a 33,945- and a 35,675-Da subunit, are primarily responsible for hepatic N-OH-2AAF sulfotransferase activity.

Reduced haloperidol/haloperidol ratios after oral haloperidol and decanoate administration in schizophrenics

1. Haloperidol and reduced haloperidol plasma concentrations were measured in thirteen stable schizophrenic patients that received both oral haloperidol and haloperidol decanoate. 2. Significant correlations between reduced haloperidol/haloperidol ratios from oral haloperidol and haloperidol decanoate occurred at week two and week 16, respectively. 3. The formation of RH was consistent during haloperidol decanoate treatment.

Pharmacokinetics of SCH-39304 in human immunodeficiency virus-infected patients following chronic oral dosing

The pharmacokinetics of SCH-39304, an investigational, orally active, broad-spectrum antifungal agent, were evaluated in 17 adult, human immunodeficiency virus-positive males. Patients were studied on days 1 and 16 and were divided into the following three treatment groups: (i) patients with culture-proven oropharyngeal candidiasis who were not receiving concurrent zidovudine therapy and who were treated with 50 mg of SCH-39304 daily (n = 6); (ii) patients with culture-proven oropharyngeal candidiasis who were receiving concurrent zidovudine therapy and who were treated with 50 mg of SCH-39304 daily (n = 5); and (iii) patients with or without oropharyngeal candidiasis who were receiving concurrent zidovudine therapy and who were treated with 200 mg of SCH-39304 daily (n = 6). All patients received a single daily dose of the study medication for 16 days. Plasma samples for SCH-39304 concentration measurement were collected for 6 h following the initial dose and for 504 h following the day 16 dose. Urine was collected for 24 h following SCH-39304 administration on days 1 and 16. All samples were assayed for SCH-39304 by gas chromatography. Wide intersubject variations in SCH-39304 plasma concentration-versus-time profiles were observed on each study day. Absorption appeared to be slow, with mean day 1 peak plasma SCH-39304 concentrations of 1.2 micrograms/ml at 2.1 h (50 mg) and 3.9 micrograms/ml at 4.0 h (200 mg) after drug administration. Mean peak plasma SCH-39304 concentrations on day 16 were 7.6 micrograms/ml at 4.3 h (50 mg) and 17.2 micrograms/ml at 3.2 h (200 mg) after drug administration. Mean elimination half-lives on day 16 for the 50- and 200-mg daily dosages were 100 and 89 h, respectively. SCH-39304 was cleared primarily unchanged in the urine. Mean areas under the plasma concentration-versus-time curve (from 0 to 24 h) on day 16 reflect a lower than expected increase with the 200-mg/day regimen (314.5 microgram.h/ml) compared with that for the 50-mg/day regimen (139.9 microgram.h/ml), suggesting the potential for reduced bioavailability at higher dosages. No significant effect of concurrent zidovudine therapy on the kinetics of SCH-39304 was observed.

Assay of progressive motion of boar spermatozoa

The motility of ejaculated boar spermatozoa was assayed by measuring the number of organisms which have entered a capillary tube in an experimental setup with the spermatozoal suspension as well as the capillary content containing the same chemically defined motility medium. This medium, used both for washing and suspending spermatozoa, contained only an isotonic tris HCl (isotris) buffer at pH 7.0. The recommended assay conditions are the following: (1) wash the spermatozoa three times with isotris buffer, (2) suspend the spermatozoa in a concentration of 10(6) spermatozoa/ml, and (3) assay at 25 degrees C with an incubation period of 60 min.

A phosphorus-31 nuclear magnetic resonance investigation of intracellular environment in human normal and sickle cell blood

Intracellular pH and 2,3-diphosphoglycerate concentration in sickle cell amenia and normal human blood samples were measured by means of phosphorus-31 nuclear magnetic resonance spectroscopy. To monitor the concentrations of various internal phosphorylated metabolites of intact red blood cells, heparinized blood samples were used and were incubated at 37 degrees C with 5.6% C92, 25% O2, and 69.4% N2. The 31P chemical shifts of phosphorylated compounds, such as 2,3-diphosphoglycerate, adenosine 5'-triphosp-ate, and inorganic phosphate, depend on pH, and by using an appropriate calibration curve, the intracellular pH of intact erythrocytes can be obtained. The intracellular pH values in fresh sickl cell blood and normal blood were found to be 7.14 and 7.29, respectively. However, the whole-blood pH, as measured by a standard pH meter, was found to be 7.54 for both types of blood. The initial concentration of 2,3-diphosphoglycerate in sickle cell blood was about 30% higher, but it was depleted much faster during incubation than that in normal blood. The difference in intracellular pH between these two types of blood samples remained constant during incubation, even after depletion of 2,3-diphosphoglycerate. These results suggest that there are differences in intracellular environment between normal and sickle cell blood. Thus, 31P nuclear magnetic resonance spectroscopy provides a fast, direct, continuous, and noninvasive way to monitor the intracellular environment of intact erythrocytes.

Nuclear magnetic resonance relaxation time studies on the manganese(II) ion complex with succinyl coenzyme A synthetase from Escherichia coli

Nuclear magnetic resonance, as well as electron paramagnetic resonance, experiments were carried out in a study of the Mn(II) ion complex with phosphorylated succinyl-CoA synthetase. For high specific activity enzyme samples, there are 3.5 +/- 0.7 metal ion binding sites per enzyme molecule with indistinguishable dissociation constants (KD = 6.9 X 10(-4) M). However, for enzyme samples with a lower specific activity yet equivalent purity, there are 1.6 strong metal ion binding sites (KD = 6.6 X 10(-4) M) and 2.0 weak metal ion binding sites (KD = 4.0 X 10(-3) M), a result that is easily reconciled with the alpha2beta2 subunit structure of the enzyme. Water proton relaxation rate measurements indicate that each strongly bound Mn(II) ion is coordinated to three water molecules. The present results strongly suggest that the existence of nearly 4 high-affinity metal binding sites per enzyme molecule is related to the integrity or configuration of that portion of the molecule which interacts with substrates.