Pharmacodynamic activity of amphotericin B deoxycholate is associated with peak plasma concentrations in a neutropenic murine model of invasive pulmonary aspergillosis

We conducted a dose fractionation study of neutropenic, corticosteroid-immunosuppressed mice to characterize the pharmacodynamic/pharmacokinetic (PK/PD) parameter most closely associated with amphotericin B (AMB) efficacy in the treatment of invasive pulmonary aspergillosis. Pharmacokinetic parameter estimates were determined by a nonparametric population pharmacokinetic analysis of plasma drug concentrations following single intraperitoneal doses (0.25, 1.0, and 3.0 mg/kg of body weight) of amphotericin B deoxycholate. Three dosage groups (0.5, 0.75, and 1.0 mg/kg) fractionated into three dosing intervals (every 8 h [q8h], q24h, or q72h) were tested to discriminate between the PK/PD parameters (the ratio of maximum concentration of drug in serum [Cmax]/MIC, the ratio of area under the concentration-time curve/MIC, and percentage of time above MIC) most closely associated with AMB efficacy over a range of clinically achievable exposures in humans. The efficacy of each regimen was determined by quantitative PCR and survival. Reductions in pulmonary fungal burden and improvements in survival were maximized at the highest peak plasma concentrations in each of the dosage groups. Reductions in pulmonary fungal burden and increased survival were most closely associated with Cmax/MIC, with maximal activity occurring as the Cmax/MIC approached 2.4. In our model, Cmax/MIC is the PK/PD parameter most closely associated with efficacy in the treatment of invasive pulmonary aspergillosis. These data predict that less frequently administered, higher dosages of AMB would optimize efficacy.

Characterization of nelfinavir binding to plasma proteins and the lack of drug displacement interactions

OBJECTIVES

To determine the characteristics of the binding of nelfinavir and active M8 to alpha1-acid glycoprotein (AAG) and human serum albumin (HSA), and to examine the displacement effects of drugs binding extensively to AAG (ritonavir and saquinavir) or to HSA (salicylic acid and valproic acid).

METHODS

Free drugs were separated by equilibrium dialysis after incubation with human plasma or purified plasma proteins and after co-incubation with potential displacers. Association constants were estimated from double-reciprocal plots of the data.

RESULTS

Nelfinavir and M8 free fractions [fractions of unbound drug (fus)] were 0.42+/-0.08% (mean+/-standard deviation) and 0.64+/-0.07%, respectively. For the two analytes, respectively, association constants were 7.25 x 10(7)/m and 3.33 x 10(7)/m for AAG and 1.11 x 10(6)/m and 7.92 x 10(5)/m for HSA. Nelfinavir fu in an AAG solution was significantly (P < 0.01) increased by the addition of ritonavir or saquinavir, whereas it was unaltered by addition of these drugs to whole plasma. Similarly, fu in an HSA solution was significantly increased (P < 0.01) by the addition of salicylic acid or valproic acid, whereas there was no difference in the free fraction in plasma.

CONCLUSIONS

The affinity of nelfinavir for human plasma proteins was higher than that of M8, and both nelfinavir and M8 showed higher affinity to AAG than to HSA. The free fraction of nelfinavir was not affected by drugs that bind extensively to AAG or albumin when these drugs were added to whole plasma in combination, suggesting a compensatory effect of alternate binding proteins.

Determination of aqueous and vitreous concentration of moxifloxacin 0.5% after delivery via a dissolvable corneal collagen shield device

PURPOSE

To determine the penetration of moxifloxacin 0.5% in the human aqueous and vitreous when delivered by a presoaked collagen shield.

SETTING

University-based clinical practice.

METHODS

Moxifloxacin 0.5% was administered before vitrectomy surgery in 10 patients using a 24-hour dissolvable cross-linked corneal collagen shield delivery device. Aqueous and vitreous samples were obtained after the shield was placed for 4 hours in the first 5 patients and for 24 hours in the second 5 patients. Assays were performed using high-performance liquid chromatography.

RESULTS

Delivery of moxifloxacin via a collagen shield revealed a mean aqueous concentration of 0.30 microg/mL +/- 0.17 (SD) 4 hours after placement (n = 5). Vitreous levels at 4 hours and aqueous and vitreous levels at 24 hours were negligible using this route of administration. Peak aqueous moxifloxacin levels occurred soon after shield placement. This is when high concentrations of moxifloxacin are most needed to clear the aqueous of bacteria. The minimum inhibitory concentration at which 90% of the isolates were inhibited for organisms commonly responsible for endophthalmitis was exceeded in the 4-hour aqueous group. Negligible concentrations were detected at 24 hours.

CONCLUSIONS

Although aqueous moxifloxacin levels achieved through the use of a collagen shield delivery device are lower than via topical drops, there are several advantages to this route of delivery that make it appealing in the immediate postoperative period. Future studies will be needed to define precisely the role of fourth-generation fluoroquinolones and presoaked collagen shields in the prophylaxis or management of intraocular infections.

New insights into the karyotypic relationships of Chinese muntjac (Muntiacus reevesi), forest musk deer (Moschus berezovskii) and gayal (Bos frontalis)

To investigate the karyotypic relationships between Chinese muntjac (Muntiacus reevesi), forest musk deer (Moschus berezovskii) and gayal (Bos frontalis), a complete set of Chinese muntjac chromosome-specific painting probes has been assigned to G-banded chromosomes of these three species. Sixteen autosomal probes (i.e. 6-10, 12-22) of the Chinese muntjac each delineated one pair of conserved segments in the forest musk deer and gayal, respectively. The remaining six autosomal probes (1-5, and 11) each delineated two to five pairs of conserved segments. In total, the 22 autosomal painting probes of Chinese muntjac delineated 33 and 34 conserved chromosomal segments in the genomes of forest musk deer and gayal, respectively. The combined analysis of comparative chromosome painting and G-band comparison reveals that most interspecific homologous segments show a high degree of conservation in G-banding patterns. Eleven chromosome fissions and five chromosome fusions differentiate the karyotypes of Chinese muntjac and forest musk deer; twelve chromosome fissions and six fusions are required to convert the Chinese muntjac karyotype to that of gayal; one chromosome fission and one fusion separate the forest musk deer and gayal. The musk deer has retained a highly conserved karyotype that closely resembles the proposed ancestral pecoran karyotype but shares none of the rearrangements characteristic for the Cervidae and Bovidae. Our results substantiate that chromosomes 1-5 and 11 of Chinese muntjac originated through exclusive centromere-to-telomere fusions of ancestral acrocentric chromosomes.

Detection of gliotoxin in experimental and human aspergillosis

Gliotoxin was measured in the lungs (mean, 3,976 +/- 1,662 ng/g of tissue) and sera (mean, 36.5 +/- 30.28 ng/ml) of mice with experimentally induced invasive aspergillosis (IA), and levels decreased with antifungal therapy. Gliotoxin could also be detected in the sera of cancer patients with documented (proven or probable) IA.

Penetration Pharmacokinetics of Topically Administered 0.5% Moxifloxacin Ophthalmic Solution in Human Aqueous and Vitreous

OBJECTIVE

To investigate the penetration of 0.5% moxifloxacin hydrochloride into the aqueous and vitreous after topical administration in humans.

METHODS

A prospective, nonrandomized study of 20 patients scheduled for vitrectomy surgery between September 1 and December 31, 2003. Aqueous and vitreous samples were obtained and analyzed after topical administration of 0.5% moxifloxacin hydrochloride, every 2 hours (q2h) or every 6 hours (q6h), for 3 days before surgery. Assays were performed using high-performance liquid chromatography.

RESULTS

Mean +/- SD moxifloxacin concentrations in the q2h group for the aqueous (n = 9) and vitreous (n = 10) were 2.28 +/- 1.23 and 0.11 +/- 0.05 microg/mL, respectively. Mean +/- SD moxifloxacin concentrations in the q6h group for the aqueous (n = 10) and vitreous (n = 9) were 0.88 +/- 0.88 and 0.06 +/- 0.06 microg/mL, respectively. The minimum inhibitory concentration for 90% of isolates (MIC(90)) was far exceeded in the aqueous for a wide spectrum of key pathogens, whereas it was not exceeded in the vitreous for several organisms. However, the minimum inhibitory concentration for 50% of the isolates was exceeded in the q2h vitreous group for Staphylococcus epidermidis, Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, Bacillus cereus, and other gram-negative pathogens.

CONCLUSIONS

The Endophthalmitis Vitrectomy Study revealed that 94.2% of isolates from postoperative endophthalmitis are gram-positive pathogens. Moxifloxacin has a spectrum of coverage that appropriately encompasses the most common organisms in endophthalmitis. The pharmacokinetic findings of this investigation show that relatively high aqueous levels can be achieved after topical administration. Further studies will help define the precise role of 0.5% moxifloxacin ophthalmic solution in the treatment of or prophylaxis against intraocular infections.

Effect of Anti-Cancer Drugs on the Binding of 125I-Fibrinogen to Two Leukaemia Cell Lines In Vitro

Anti-cancer drugs may be able to inhibit tumour growth and metastasis by blocking fibrinogen- and/or fibrin-related pathways. To test this hypothesis, the effect of various anti-neoplastic drugs on the binding of 125I-Fibrinogen to two leukaemia cell lines, HL60 and P388, was investigated. All the drugs tested inhibited the binding of fibrinogen to leukaemia cells. This effect was particularly marked for drugs that act as inhibitors of protein synthesis. Since these anti-neoplastic drugs do not have anti-coagulant actions, these results provide evidence for the potential of targeting tumour fibrinogen as a new form of cancer chemotherapy.

Pharmacodynamics of caspofungin in a murine model of invasive pulmonary aspergillosis: evidence of concentration-dependent activity

BACKGROUND

A paucity of data exists regarding the pharmacodynamics of caspofungin (CAS) during invasive pulmonary aspergillosis (IPA). We conducted a dosage-fractionation study to characterize the in vivo pharmacodynamics of CAS activity during IPA, using immunosuppressed mice inoculated intranasally with Aspergillus fumigatus.

METHODS

After single intraperitoneal doses (0.25, 1.0, and 4.0 mg/kg), plasma CAS concentrations were assayed by high-performance liquid chromatography. The pharmacokinetic data were analyzed by nonparametric population pharmacokinetic analysis. Three dosage groups (0.25, 1.0, and 4.0 mg/kg) fractionated into 3 different dosing intervals (q6, q24, or q48 h) were then used to evaluate the pharmacokinetic/pharmacodynamic effects (percentage of time greater than the minimum effective concentration [MEC], 96-h area under the plasma concentration curve:MEC ratio, and peak concentration in plasma [Cmax]:MEC ratio) at clinically achievable exposures. Mice were treated for 96 h and were then euthanized, and their lungs were harvested for analysis of pulmonary fungal burden by real-time quantitative polymerase chain reaction.

RESULTS

A concentration-dependent reduction in mean pulmonary fungal burden was evident in mice in the 1 mg/kg dosage-fractionation group, with significantly lower mean pulmonary fungal burden in mice dosed q48 h versus q6 h (P < .01). A paradoxical increase in pulmonary fungal burden was observed in the highest dosage-fractionation group.

CONCLUSIONS

CAS demonstrates concentration-dependent pharmacodynamics in the treatment of IPA. The Cmax : MEC ratio appears to be the parameter most closely associated with the reduction of pulmonary fungal burden.

Determination of vitreous, aqueous, and plasma concentration of orally administered voriconazole in humans

OBJECTIVE

To investigate the penetration of voriconazole, a new-generation triazole antifungal agent, into the vitreous and aqueous humor after oral administration.

METHODS

A prospective, nonrandomized clinical study included 14 patients scheduled for elective pars plana vitrectomy surgery between December 1, 2002, and February 28, 2003, at the Cullen Eye Institute, Houston, Tex. Aqueous, vitreous, and plasma samples were obtained and analyzed from 14 patients after oral administration of two 400-mg doses of voriconazole taken 12 hours apart before surgery. Assays were performed by means of high-performance liquid chromatography.

RESULTS

Mean +/- SD voriconazole concentrations in plasma (n = 14), vitreous (n = 14), and aqueous (n = 11) were 2.13 +/- 0.93 microg/mL, 0.81 +/- 0.31 microg/mL, and 1.13 +/- 0.57 microg/mL, respectively. Mean +/- SD sampling times after oral administration of the second voriconazole dose for plasma, vitreous, and aqueous were 2.4 +/- 0.6 hours, 3.0 +/- 0.5 hours, and 2.9 +/- 0.5 hours, respectively. The percentages of plasma voriconazole concentration achieved in the vitreous and aqueous were 38.1% and 53.0%, respectively. Mean vitreous and aqueous minimum inhibitory concentrations for 90% of isolates (MIC(90)) were achieved against a wide spectrum of yeasts and molds, including Aspergillus species and Candida species, along with many other organisms.

CONCLUSIONS

Orally administered voriconazole achieves therapeutic aqueous and vitreous levels in the noninflamed human eye, and the activity spectrum appears to appropriately encompass the most frequently encountered mycotic species involved in the various causes of fungal endophthalmitis. Because of its broad spectrum of coverage, low MIC(90) levels for the organisms of concern, good tolerability, and excellent bioavailability with oral administration, it may represent a major advance in the prophylaxis or management of exogenous or endogenous fungal endophthalmitis.

Human intraocular penetration pharmacokinetics of moxifloxacin 0.5% via topical and collagen shield routes of administration

PURPOSE

To determine penetration of moxifloxacin 0.5% into human aqueous and vitreous via topical and collagen shield routes of administration.

METHODS

Moxifloxacin 0.5% was administered prior to vitrectomy surgery through one of three routes: topical drops every 2 hours for 3 days, versus topical drops every 6 hours for 3 days, versus delivery using a 24-hour dissolvable cross-linked corneal collagen shield. Aqueous and vitreous moxifloxacin concentrations were assayed using high-performance liquid chromatography.

RESULTS

Mean moxifloxacin concentrations in the every-2-hour group for aqueous (n = 9) and vitreous (n = 10) were 2.28 +/- 1.23 microg/mL and 0.11 +/- 0.05 microg/mL, respectively. Mean moxifloxacin concentrations in the every-6-hour group for aqueous (n = 10) and vitreous (n = 9) were 0.88 +/- 0.88 microg/mL and 0.06 +/- 0.06 microg/mL, respectively. Levels of minimum inhibitory concentration at which 90% of isolates are inhibited (MIC90) were far exceeded in the aqueous for a wide spectrum of pathogens that most commonly cause postoperative endophthalmitis. Moxifloxacin concentration in the vitreous did not exceed the MIC90 for several key organisms. Delivery of moxifloxacin via a collagen shield revealed a mean aqueous concentration of 0.30 +/- 0.17 microg/mL 4 hours after placement (n = 5). Vitreous levels at 4 hours, as well as aqueous and vitreous levels at 24 hours, were negligible using this route of administration.

CONCLUSIONS

The findings of this investigation reveal that topically administered moxifloxacin 0.5% can achieve relatively high aqueous concentrations. Although aqueous moxifloxacin levels achieved through the use of a collagen shield delivery device are lower, there are several advantages to this route of delivery that make it appealing in the immediate postoperative period. Future studies will be needed to precisely define the role of fourth-generation fluoroquinolones and presoaked collagen shields in the prophylaxis or management of intraocular infections.

An LC-MS-MS method for the determination of nevirapine, a non-nucleoside reverse transcriptase inhibitor, in human plasma

A sensitive and rapid liquid chromatography tandem mass spectrometry (LC-MS-MS) method has been developed to measure the levels of the HIV-1 non-nucleoside reverse transcriptase inhibitor nevirapine (NVP) in human plasma. The analyte and internal standard (IS) are isolated from plasma by a simple perchloric acid precipitation of plasma proteins followed by centrifugation. LC-MS-MS in positive mode used pairs of ions at m/z of 267/226 for NVP and 628/421 for the IS, respectively. Two linear calibration curves were established for quantitation of NVP with the low curve ranging from 25 to 1000 ng/ml and the high curve ranging from 1000 to 10,000 ng/ml. Mean inter- and intra-assay coefficients of variation (CVs) over the ranges of the two standard curves were less than 10%. The overall recovery of NVP was 92.4%.

Simultaneous determination of five HIV protease inhibitors nelfinavir, indinavir, ritonavir, saquinavir and amprenavir in human plasma by LC/MS/MS

A sensitive and rapid liquid chromatography tandem mass spectrometry (LC-MS-MS) method has been developed to measure the levels of five HIV protease inhibitors nelfinavir (NFV), indinavir (IDV), ritonavir (RTV), saquinavir (SQV) and amprenavir (APV) in human plasma. The analytes and internal standard are isolated from plasma by a simple acetonitrile precipitation of plasma proteins followed by centrifugation. LC-MS-MS in positive mode used pairs of ions at m/z of 568.4/330.0, 614.3/421.2, 720.9/296.0, 671.1/570.2 and 505.9/245.0 for NFV, IDV, RTV, SQV and APV, respectively and 628/421 for the internal standard. Two 1/x weighted linear calibration curves for each analyte were established for quantitation with the low curve ranging from 5 to 1000 ng/ml and while the high curve ranging from 1000 to 10,000 ng/ml. Mean inter- and intra-assay coefficients of variation (CVs) over the ranges of the standard curves were less than 10%. The overall recovery of NFV, IDV, RTV, SQV and APV were 88.4, 91.4, 92.2, 88.9 and 87.6%, respectively.

Itraconazole preexposure attenuates the efficacy of subsequent amphotericin B therapy in a murine model of acute invasive pulmonary aspergillosis

Antagonism has been described in vitro and in vivo for azole-polyene combinations against Aspergillus species. Using an established murine model of invasive pulmonary aspergillosis, we evaluated the efficacy of several amphotericin B (AMB) dosages given alone or following preexposure to itraconazole (ITC). Mice were immunosuppressed with cortisone acetate and cyclophosphamide. During immunosuppression, animals were administered either ITC solution (50 mg/kg of body weight) or saline by oral gavage twice daily for 3 days prior to infection. Infection was induced by intranasally inoculating mice with a standardized conidial suspension (1 x 10(8) CFU/ml) of Aspergillus fumigatus strain AF 293. AMB was then administered by daily intraperitoneal injections (0.25, 0.5, 1.0, and 3.0 mg/kg) starting 24 h after inoculation and continuing for a total of 72 h. Drug pharmacokinetics of AMB and ITC in plasma were determined by high-performance liquid chromatography. Four different endpoints were used to examine the efficacy of antifungal therapy: (i) viable counts from harvested lung tissue (in CFU per milliliter), (ii) the whole-lung chitin assay, (iii) mortality at 96 h, and (iv) histopathology of representative lung sections. At AMB doses of >0.5 mg/kg/day, fewer ITC-preexposed mice versus non-ITC-preexposed mice were alive at 96 h (0 to 20 versus 60%, respectively). At all time points, the fungal lung burden was consistently and significantly higher in animals preexposed to ITC, as measured by the CFU counts (P = 0.001) and the chitin assay (P = 0.03). Higher doses of AMB did not overcome this antagonism. ITC preexposure was associated with poorer mycological efficacy and survival in mice treated subsequently with AMB for invasive pulmonary aspergillosis.

A direct determination of thymidine triphosphate concentrations without dephosphorylation in peripheral blood mononuclear cells by LC/MS/MS

A rapid, sensitive and specific analytical method with minimal sample preparation for the measurement of thymidine triphosphate (TTP) in peripheral blood mononuclear cells (PBMC) by LC/MS/MS has been developed. PBMC were separated from whole blood or buffy coat. The analyte and internal standard were extracted from PBMC with 70% methanol (pH 7.2). These extracts after centrifugation were directly injected onto LC/MS/MS without need for any further sample preparation. The calibration curve was linear over the range 0.8-800 ng/ml. Mean inter- and intra-assay coefficients of variation (CVs) over the range of the standard curve were less than 10%. The overall recovery of TTP was 103.5%.

Age changes in orthodontic treatment need: a longitudinal study of 10- and 13-year-old children, using the Dental Aesthetic Index

The Dental Aesthetic Index (DAI) was used to assess the prevalence of unmet orthodontic treatment need in 150 13-year-old schoolchildren in Dunedin, New Zealand, and to compare the findings with those obtained in the same children at 10 years of age. Fewer 13-year-olds (27%) had a "mandatory" need of orthodontic treatment than when they were 10 years old (33%), 20% had "no/little" need for orthodontic treatment, 33% had an "elective" need for treatment and 20% had a "desirable" need for treatment. The fall in DAI scores is attributed to over-sensitivity of the Index to mixed dentition traits. When the individual scores were analysed, only 7% of the 10-year-olds were given the same scores as when they were 13 years old, 52% were given higher scores and 41% were given lower scores. This disagreement between scores was masked to a limited extent by the DAI categories: 49% of the 10-year-olds were assigned to the same DAI category at 13 years of age, 20% to a greater treatment-need category and approximately 30% to a lower treatment-need category. The DAI, in common with other malocclusion indices, is unreliable over time because it is affected by developmental changes in the occlusal traits measured.

Incidence of presbycusis of Korean populations in Seoul, Kyunggi and Kangwon provinces

Presbycusis, a bilateral sensorineural hearing loss caused by changes in the inner ear, is related to multiple factors such as noise exposure and otologic disease. In institute-based studies, we tried to determine the incidence of presbycusis in Korean populations living in Seoul, Kyunggi and Kangwon provinces by gender and age groups. The subjects were people who had visited health promotion centers. Pure tone audiometry was done over 20 years on 6,028 subjects. In a community-based study, the subjects were elderly residents of Kanghwa-do area. There were no obvious factors that could cause hearing impairment in the subjects. For the pure tone audiometry, hearing threshold was obtained by using the six-dimension method. The incidence of presbycusis for subjects aged 65 years and older was 37.8% and 8.3% for > or = 27 dB HL criterion and > or = 41 dB HL criterion, respectively. The incidence increased with age. A statistically significant difference in the hearing threshold was found between men and women aged 65 years or older. No differences were found between the community-based study and the institute- based studies. There was a high incidence (about 40%) of presbycusis among Koreans aged 65 years or older (for > or = 27 dB HL criterion). With an aging population, we anticipate that this report could be used to provide a basic data for the study of presbycusis.

A longitudinal study of orthodontic treatment need in Dunedin schoolchildren

The Index of Orthodontic Treatment Need (IOTN) was used to assess unmet orthodontic treatment need in 152 13-year-old Dunedin schoolchildren, and to compare the findings with those obtained in the same children 3 years previously. The children were randomly selected from Dunedin schools as 10-year-olds, and had not received orthodontic treatment. Approximately 86 percent of the 13-year-old children had "No-little" need for orthodontic treatment when assessed by the child-assessed Aesthetic Component (AC) and the examiner-assessed AC. Slightly less than half the children had "No-little" need for orthodontic treatment when assessed with the Dental Health Component (DHC). More 10- and 13-year-old children "Needed" orthodontic treatment with the DHC than with the AC. Both the examiner-assessed AC and the DHC assessed significantly fewer 13-year-olds as needing orthodontic treatment than the same children as 10-year-olds. Complete agreement between the grades assigned at 10 and 13 years occurred in 30-43 percent of the children and, in the treatment-need categories, between 53 percent (DHC) and 84 percent (child-assessed AC) of the children. The fall in treatment need over the 3-year period may be due to selection bias, over-sensitivity of the IOTN to mixed dentition traits, or both. Although a number of 10-year-old children were assigned different grades as 13-year-olds, many remained within the same treatment category. The apparent stability of the IOTN to assess treatment need in 10- and 13-year-old children is attributed to the grouping of different occlusal traits in the same treatment-need category, and to the small number of treatment-need categories in each component.

Induction of gastritis and gastric ulcer in Mongolian gerbils infected with Helicobacter pylori

OBJECTIVE

To induce the model of Mongolian gerbil infected by Helicobacter pylori (HP) and to observe the changes of the infiltration and the proliferation of inflammatory cells before and after the bactericidal treatment.

METHODS

The animal model of HP infection was induced by inoculating the HP strain (American Type Culture Collection) to male Mongolian gerbil MGS/Sea (SPF). Half a month, 1 month and 3 months after inoculation, kill the animals and make HE staining and immunohistochemistry staining of the stomach to observe the pathological changes.

RESULTS

The infiltration of a great number of inflammatory cells was observed with the center of the mucosa of pylorus at the second week of HP infection. At the 3rd month of infection, ulcer appeared near the lesser curvature side of the pylorus. On the early stage of infection, the lesion was acute inflammation characterized by the neutrophilic infiltration, and then transformed into the chronic inflammation characterized by the lymphatic infiltration and the wide formation of lymphatic follicles.

CONCLUSION

Mongolian gerbil is an ideal and standard animal model of HP infection.

Neuroendocrine evidence for dopaminergic actions of hypericum extract (LI 160) in healthy volunteers

BACKGROUND

We studied the effect of a single dose of a formulation of a methanolic extract of Hypericum perforatum (HP), also known as St. John's wort, on plasma concentrations of growth hormone (GH), prolactin (PRL), and cortisol (CORT) in 12 healthy male volunteers.

METHODS

Subjects received 9 tablets of the finished product Jarsin 300 and placebo in a double-blind, balanced-order, cross-over design.

RESULTS

Following HP relative to placebo, there was a significant increase in plasma GH and a significant decrease in plasma PRL. Plasma CORT levels were unchanged.

CONCLUSIONS

Taken together with data from animal experimental studies, the findings suggest that this dose of HP may increase some aspects of brain dopamine function in humans.

Globular domains of agrin are functional units that collaborate to induce acetylcholine receptor clustering

Agrin, an extracellular matrix protein involved in neuromuscular junction formation, directs clustering of postsynaptic molecules, including acetylcholine receptors (AChRs). This activity resides entirely in the C-terminal portion of the protein, which consists of three laminin-like globular domains (G-domains: G1, G2 and G3) and four EGF-like repeats. Additionally, alternate mRNA splicing yields G-domain variants G2(0,4) with 0- or 4-amino-acid inserts, and G3(0, 8,11,19) with 0-, 8-, 11- or 19-amino-acid inserts. In order to better understand the contributions of individual domains and alternate splicing to agrin activity, single G-domains and covalently linked pairs of G-domains were expressed as soluble proteins and their AChR clustering activity measured on cultured C2 myotubes. These analyses reveal the following: (1) While only G3(8) exhibits detectable activity by itself, all G-domains studied (G1, G2(0), G2(4), G3(0) and G3(8)) enhance G3(8) activity when physically linked to G3(8). This effect is most pronounced when G2(4) is linked to G3(8) and is independent of the order of the G-domains. (2) The deletion of EGF-like repeats enhances activity. (3) Increasing the physical separation between linked G1 and G3(8) domains produces a significant increase in activity; similar alterations to linked G2 and G3(8) domains are without effect. (4) Clusters induced by two concatenated G3(8) domains are significantly smaller than all other agrin forms studied. These data suggest that agrin G-domains are the functional units which interact independently of their specific organization to yield AChR clustering. G-domain synergism resulting in biological output could be due to physical interactions between G-domains or, alternatively, independent interactions of G-domains with cell surface receptors which require spatially localized coactivation for optimal signal transduction.

Elongated stylohyoid process: a report of three cases

The stylohyoid process is part of the stylohyoid chain--the styloid process, the stylohyoid ligament, and the lesser cornu of the hyoid bone. The stylohyoid chain is derived from the second branchial arch. Mineralisation of the stylohyoid ligament and ossification at the tip may increase the length of the styloid process. An elongated stylohyoid or styloid process is considered to be the source of craniofacial and cervical pain commonly known as Eagle's syndrome. In some instances the stylohyoid process may be considerably elongated, yet remain asymptomatic. This paper reports three patients with elongated stylohyoid processes discovered incidentally on routine radiographic examination.

[A flavonoid compound in Ginkgo biloba L. leaves]

One compound was isolated for the first time from ethyl acetate extract of Ginkgo biloba leaves and identified as kaempferol-3-O-rhamnoside by spectroscopic methods.

[Chemical constituents of flavonoids in the leaf of Ginkgo biloba L]

A compounds were isolated from the ethyl acetate extract of Ginkgo biloba leaves for the first time and was identified as 5,7,4'-trihydroxy-flavone by spectroscopic methods.