Comparison of BrdUrd and [3H]TdR incorporation to estimate cell proliferation, cell loss, and potential doubling time in tumor xenografts

In this study, two different methods of estimating cell proliferation were compared: cell loss and potential growth rate of xenografted head and neck cancer grown in nude mice based on the detection of DNA incorporation of bromodeoxyuridine (BrdUrd) in one method, and [3H]thymidine ([3H]TdR) in the other. The 21-d-old xenografts were labelled in vivo, either with BrdUrd or [3H]TdR and excised at intervals during 65.5 h. In tumors containing BrdUrd, the percent labelling was measured in mid-S and mid-G1 phase windows of cytograms from bivariate DNA flow cytometry (FCM). In [3H]TdR-labelled tumors, the percent labelled mitoses (PLM) was determined by light microscopy evaluation of autoradiographs. With a computer program based on a theoretical model, the percent labelling versus time after injection was used to analyze cell cycle time, cell loss, tumor growth fraction, and potential doubling time. The values calculated from DNA incorporation with BrdUrd agreed well with those obtained from labelling with [3H]TdR, i.e., cell cycle time 2.3 vs. 2.4 d, and growth fraction 67 vs. 70%. The estimated potential doubling time was 3.1 d and cell loss factor 40% by both methods. Flow cytometry analysis of BrdUrd-labelling is considerably faster than the evaluation of [3H]TdR-labelling, and the present results provide further support for the BrdUrd labelling method as a promising alternative to the PLM method in cell cycle studies designed to evaluate the relevance of cell proliferative properties in relation to biological behavior in xenografted head and neck cancer.

Clonal chromosome abnormalities and in vitro growth characteristics of classical and cellular schwannomas

Cytogenetic analysis was performed on 12 schwannomas, 10 classical and two of the cellular type. Electron microscopic examination of cultured cells from two classical and two cellular schwannomas revealed features compatible with a Schwann cell differentiation. Immunohistochemical analysis of the cultures demonstrated immunoreactivity for S-100 protein in 6 of 6 cases and for vimentin in 2 of 2 cases of classical schwannoma, thus further supporting the authenticity of the cultured cells. Cultured cells from one cellular schwannoma also exhibited immunoreactivity for glial fibrillary acid protein (GFAP). Cytogenetic analysis of the 12 tumors revealed clonal abnormalities in 10 of the cases. In the majority of tumors, cells with a normal karyotype coexisted with different abnormal clones and sporadic deviations. Numerical changes predominated and were found in all tumors, while structural rearrangements were detected in eight tumors. The most common abnormality was clonal or sporadic loss of chromosome 22, which was found in all cases. Other clonal abnormalities included loss of one sex chromosome found in five cases, -15 found in three cases, and -12, +5, +7, +20 found in two cases each. These results provide further evidence in support of a role for loss of chromosome 22 in the pathogenesis of schwannomas. Our findings also indicate that there exist several different evolutionary pathways for schwannomas, and that some of these are shared by several other types of benign and malignant tumors of the nervous system.

Binding of herpes simplex virus to cellular heparan sulphate, an initial step in the adsorption process

It has been suggested that heparan sulphate has a receptor function in the initial phase of the attachment of herpes simplex virus (HSV) to cells. We have studied the influence of glycosaminoglycans on cell adsorption of, and plaque formation by, HSV-1 and HSV-2, with regard to the role of saccharide structure, chain length and charge density. Heparin and highly-sulphated heparan sulphate (1.5 sulphate groups/disaccharide unit), but neither chondroitin sulphate nor dermatan sulphate, were found to compete with the cellular receptor for attachment of HSV. Heparan sulphate preparations of low sulphate content (0.5 and 0.7 sulphate groups/disaccharide unit) failed to show any significant interaction with HSV. Oligosaccharides generated by partial deaminative cleavage of heparin were used to determine the minimum molecular size required for the binding of virus; the smallest oligosaccharide which reacted with HSV was composed of 10 monosaccharide units. The importance of charge density was demonstrated more directly by subfractionation of the heparin dodecasaccharide fraction by anion-exchange HPLC. The virus-binding capacities of the four resulting dodecasaccharide subfractions increased from the least sulphated to the most heavily sulphated fraction. The results reported are discussed in relation to virus-receptor interactions involved in the attachment of HSV, including the reported binding of HSV to the fibroblast growth factor receptor.

Rearrangement of 9p13 as the primary chromosomal aberration in adenoid cystic carcinoma of the respiratory tract

Two adenoid cystic carcinomas, one of the nasal cavity, the other a bronchial tumor, were cytogenetically analyzed. The former had a t(6;9)(q21-22;p 13-21) as the sole karyotypic abnormality. The latter had two related abnormal clones, resulting in the mosaic karyotype 46,XY,t(9;17)(p13;p13)/46,Y,t(X;6)(p22;q23),t(9;17)(p13;p13). The karyotypic profiles of the two cases, the only respiratory tract adenoid cystic carcinomas that have been cytogenetically characterized, differ little from those of previously reported adenoid cystic carcinomas of the major salivary glands, underscoring the fundamental biologic similarity among these tumors even when they develop from different structures and in different anatomical sites and organs. Because in the second case the t(9;17) obviously must have preceded the t(X;6), we conclude that both tumors had rearrangement of 9p13 as the primary cytogenetic change. The data thus add to the evidence that 6q changes are frequent, albeit at least sometimes secondary, aberrations in malignant salivary gland tumors. A subset of adenoid cystic carcinomas instead have rearrangement of 9p as the primary, and presumably pathogenetically essential, abnormality.

Caries-preventive effect of dentifrices containing various types and concentrations of fluorides and sugar alcohols

The caries-inhibiting effect of unsupervised daily use of four different toothpastes was compared in a 3-year clinical and microbiological study: (1) 0.8% sodium monofluorophosphate (MFP) with 3% xylitol and 6% sorbitol; (2) 0.03% sodium fluoride with 3% xylitol and 6% sorbitol; (3) 0.8% MFP with 9% sorbitol, and (4) 0.03% sodium fluoride with 9% sorbitol. In all 284 children, 12-13 years old at baseline, took part in the study. After 3 years, no statistically significant differences were found between the different toothpaste groups concerning either development of initial or gross caries lesions or number of mutans streptococci and lactobacilli in saliva. However, children with no detectable approximal caries at baseline, who used the MFP toothpaste with the xylitol-sorbitol mixture, showed a lower (p less than 0.05) caries increment as compared with children who used the MFP toothpaste with sorbitol alone.

Two daily subcutaneous injections of fragmin as compared with intravenous standard heparin in the treatment of deep venous thrombosis (DVT)

In a prospective, randomized, open study 119 consecutive patients with phlebographically verified deep venous thrombosis (DVT) of the leg (36% distal and 64% proximal) were treated either with a low molecular weight heparin (Fragmin, Kabi-Vitrum) subcutaneously (120 anti-FXa U/kg) twice daily or standard heparin (SH) as continuous intravenous infusion (480 IU kg-1 day-1). The Fragmin doses were adjusted to achieve an anti-FXa activity of 0.2-0.4 U/ml before injection and not greater than 1.5 U/ml 4 h after the morning injection. The SH dose was modified to prolong the APTT 2-3 times. Repeat phlebography after 5-7 days showed improvement in 34/45 patients (76%) in the Fragmin group and in 30/49 patients (61%) in the SH group and progress in 2/45 (4%) and 3/49 (6%), respectively. The mean Marder scores decreased from 18.7 +/- 12.1 to 15.7 +/- 12.7 in the Fragmin group and from 16.9 +/- 12.0 to 14.4 +/- 11.8 in the SH group (ns). Two patients in the SH group and none in the Fragmin group had major bleedings. After 22 +/- 7 months follow up 6 rethromboses had occurred in the SH group and 4 in the Fragmin group. Postthrombotic signs and symptoms were similar in both groups. We conclude that two daily sc Fragmin doses seem as effective and safe as continuous SH in the treatment of DVT of the leg.

Parathyroid adenoma with t(1;5)(p22;q32) as the sole clonal chromosome abnormality

Cytogenetic investigation of short-term cultures from a parathyroid adenoma revealed a t(1;5)(p22;q32) as the sole clonal chromosomal aberration. Karyotypic abnormalities have not previously been described in this tumor type.

Pharmacokinetics of oral noscapine

The relative bioavailability in 20 healthy volunteers of 100 mg, 200 mg and 300 mg tablets of noscapine and 200 mg as a solution has been assessed in a four-way cross-over study, with repeated administration of the 200 mg dose to assess intraindividual variability. There was a disproportionate increase in the AUC of noscapine tablets, as a 3-fold increase in dose produced a 9-fold rise in AUC. This dose-dependency could mainly be attributed to saturable first-pass metabolism of the drug. Administration of noscapine as a solution resulted in a significantly higher maximal concentration at an earlier time-point and a higher AUC than the corresponding dose as tablets. Repeated administration of noscapine tablets and solution yielded higher AUC on the second dosing occasion. No cause for this carry-over effect was found, and the contribution of remaining noscapine was negligible. The terminal half-life of noscapine, which was independent of formulation or dose size was 4.5 h. Both inter- and intraindividual variability in noscapine kinetics were very high, e.g. 73% and 51% CV of the AUC for the 200 mg tablet.

Effects of system peaks in a coupled column system for noscapine and its metabolites

System peaks created in a coupled column system, after transfer of the precolumn mobile phase to the analytical column have been investigated. Co-elution of an analyte with a system peak may affect the chromatographic performance of the analyte. The possibility of using the peak compression effect, in order to increase the detectability of the compounds noscapine, narcotoline and cotarnine, respectively, is studied. Three different mobile phases for the analytical column have been tested, the first contained a co-ion, the second a counter-ion and the last both a co-ion and a counter-ion. A compressed noscapine peak is obtained not only when it is eluted in a positive gradient of the co-ion in the first system, but also in a positive gradient of the counter-ion in the second system. Slightly compressed narcotoline and cotarnine peaks are obtained in the third system as long as they eluted before the deficiency peak of the counter-ion.

Determination of noscapine and its metabolites in plasma by coupled-column liquid chromatography

Noscapine, narcotoline and cotarnine were quantified in deproteinized plasma samples by using a coupled-column liquid chromatographic system. The drug and the metabolites were first separated into two groups on a short polar precolumn (-CN) with an acidic mobile phase, containing a low content of acetonitrile. The metabolites were transferred to a hydrophobic analytical column (C18) and separated with a mobile phase containing a counter ion and a co-ion in an acidic buffer with an high acetonitrile content. Noscapine was transferred to another hydrophobic analytical column (C18) with a mobile phase containing a counter ion in an acidic buffer with an high acetonitrile content. Ultraviolet detection at 310 nm was used for all three compounds. The limits of quantitation were 9 ng/ml for noscapine, 13 ng/ml for cotarnine and 20 ng/ml for narcotoline. The within-day precisions were better than 6% (relative standard deviation), and the absolute recoveries were above 82%.

Determination of bromhexine in plasma by reversed-phase liquid chromatography. Interference of lipoproteins on extraction

Extraction of the hydrophobic tertiary amine bromhexine from plasma using cyclohexane-heptafluorobutanol (99.5:0.5, v/v) was studied at different pH values. The extraction yield from buffer solutions was quantitative at pH greater than 4.1, but from plasma the extraction yield decreased with increasing pH. Furthermore, at pH 8.4 the extraction yield varied greatly (56-99%) in different human plasma. The addition of lipoproteins to phosphate buffer, at pH 8.1, decreased the extraction yields considerably. Quantitative extraction from plasma was obtained by using a very long extraction time at pH 8.4 or by decreasing the pH to 5.4. The chromatographic system consisted of a reversed-phase column (Nucleosil C18, 5 microns) with an acidic mobile phase (methanol-phosphate buffer, pH 2) containing an aliphatic tertiary amine. UV detection at 308 or 254 nm was used. The limit of quantitation was 5 ng/ml using 3.00 ml of plasma and detection at 254 nm. The intra-assay precision for bromhexine was better than 3.6% at 5 ng/ml.

Effects of system peaks in ion-pair reversed-phase liquid chromatography for noscapine and metabolites

System peaks were generated in an ion-pair reversed-phase system by co-injection of an alkylsulphate with the analytes. The acidic mobile phase contained acetonitrile and an aliphatic tertiary amine as a co-ion. The retention time of the system peak was regulated by the concentration and hydrophobicity of the co-ion and the alkylsulphate. The peak performance of the analytes was affected by co-elution with a system peak. Both peak distortions and improvements appeared, and the principles for the latter could be applied in a dual-column system involving trace enrichment and column switching.

Gas chromatographic analysis of flunixin in equine urine after extractive methylation

A quantitative method for the analysis of flunixin, 2-(2-methyl-3-trifluoromethylanilino) nicotinic acid, in equine urine by gas chromatography with nitrogen-phosphorus detection has been developed. Flunixin and the internal standard, mefenamic acid, N-(2,3-xylyl) anthranilic acid, were analysed after extractive methylation of the carboxylic acid group using methyl iodide. The extraction and alkylation conditions of flunixin and mefenamic acid have been studied. The detection limit of the method was 0.25 mumol/l flunixin in urine (74 ng/ml). Flunixin was found to be conjugated to 96.5% in equine urine, and the conjugate was spontaneously hydrolysed to free flunixin. This approach can also be used to confirm the presence of flunixin or mefenamic acid in horse urine in the doping control of racehorses.

Detection of an immunoglobulin M response in the elderly for early diagnosis of respiratory syncytial virus infection

The indirect fluorescent-antibody technique was compared with indirect and mu-capture enzyme-linked immunosorbent assays for the detection of respiratory syncytial virus (RSV) immunoglobulin M (IgM) in the elderly. Sera from 47 patients (mean age, 70 years) with acute lower respiratory tract infections caused by RSV were investigated. Specific IgM was detected in 81% (38 of 47) of the patients. The fluorescent-antibody technique, which gave 70% positive results, proved to be the most sensitive of the three methods. An IgM response was seldom seen in sera from the elderly within the first week of disease, but was present in 85% of sera (33 of 39) collected between days 11 and 30 of disease. In some patients it persisted for more than 6 weeks. Detection of IgM was found to be a useful tool for the diagnosis of RSV infections in elderly patients.

Herpes simplex virus infection of the human sensory neuron. An electron microscopy study

Herpes simplex virus (HSV) type 1 was used to infect cultures of human embryonic dorsal root ganglion cells. Infected cultured were studied by electron microscopy. Viral nucleocapsids were observed to be internalized into neuronal cells bodies and neuritic extensions by fusion of the viral envelope and the plasma membrane. No signs of internalization by endocytosis were noted. Nucleocapsids were transported in neurites and were within 2 hrs postinfection found located near the microtubules and close to the nuclear pores in the perikaryon. A primary envelopment of nucleocapsids occurred at the inner lamina of the nuclear membrane and virions appeared between the two laminae. Presence of non-enveloped nucleocapsids outside the nuclear membrane and in close contact with the endoplasmic reticulum suggested that nucleocapsids could pass to the cytoplasmic side probably by de-envelopment at the outer nuclear membrane. A secondary envelopment occurred at the endoplasmic reticulum where the virions also became enclosed in transport vesicles. Enveloped virus appearing in the cytoplasm of neurons and neuritic extensions was always found only inside these transport vesicles. During their passage through the cytoplasm the virion-transport vesicle complexes were surrounded by smaller lysosome-like vesicles possibly derived from the Golgi apparatus. Fusion reactions between vesicles with virions and the smaller vesicles seemed to occur. We discuss if in this way the virion-transport vesicle complexes might be provided with glycosyl transferases and substrates necessary for maturation and completion of glycosylation of the viral envelope glycoproteins. The transport vesicles seemed essential for egress of virions from the infected cell by releasing virus when fusing with the plasma membrane.

Pharmacokinetics and bioavailability of reduced and oxidized N-acetylcysteine

The pharmacokinetics and bioavailability of N-acetylcysteine (NAC) have been determined after its intravenous and oral administration to 6 healthy volunteers. According to a randomized cross-over design each subject received NAC 200 mg i.v. and 400 mg p.o., and blood samples were collected for 30 h. Reduced NAC had a volume of distribution (VSS) of 0.59 l.kg-1 and a plasma clearance of 0.84 l.h-1.kg-1. The terminal half-life after intravenous administration was 1.95 h. The oral bioavailability was 4.0%. Based on total NAC concentration, its volume of distribution (VSS) was 0.47 l.kg-1 and its plasma clearance was 0.11 l.h-1.kg-1. The terminal half-life was 5.58 h after intravenous administration and 6.25 h after oral administration. Oral bioavailability of total NAC was 9.1%.

Determination of dextromethorphan and its metabolites in plasma by dual column liquid chromatography and fluorimetric detection

Dextromethorphan and its metabolites were determined in plasma by a dual column liquid chromatographic switching system, after a prepurification on Sep-Pak C(18) cartridges. A polar precolumn (CN) and two hydrophobic analytical columns (C(18)) were used with mobile phases optimised regarding trace enrichment, selectivity and speed by the content of organic modifier. Dextromethorphan and its metabolites could be quantified at 5 ng ml(-1) with an intra-assay precision better than 6% (RSD).

Determination of N-acetylcysteine, intact and oxidized, in plasma by column liquid chromatography and post-column derivatization

N-Acetylcysteine in plasma may exist as intact N-acetylcysteine (NAC) or be oxidized to disulphides, either as a dimer or mixed with other thiol-containing compounds. To prevent oxidation of NAC, whole blood was immediately centrifuged after collection and the plasma proteins were precipitated with perchloric acid. NAC was measured by direct injection of the supernatant into the chromatographic system and the oxidized forms, coupled to small sulphides (ONACS), were determined after reductive cleavage of all NAC disulphides in the supernatant with dithiothreitol before injection. The total plasma concentration of the compound, i.e., including the fraction coupled to proteins (ONACP), was assayed after an initial reduction of the disulphide linkages in plasma. After subsequent precipitation of proteins, the supernatant was directly injected. The chromatographic system was a reversed-phase column (C18) with an acidic mobile phase. After a fast (less than 6 s) post-column reaction with pyrenemaleimide, NAC was detected by fluorimetry. The contribution to the band broadening by the reactor was about 10%. The limit of quantification of NAC in plasma was 240 nM, with an intra-assay precision of 14%.

Fetal heart rate pattern before and after paracervical anesthesia. A prospective study

A prospective study of the fetal heart rate pattern during labor before and after paracervical blockade (PCB) was performed. The material comprised 469 women in labor, or 28% of 1673 women delivered during a 6-month period. The majority of the anesthesias (87%) were administered by specially trained midwives. Bupivacain (Marcain) was the anesthetic used. The injections were made at four different points at a cervical diameter of 3-9 cm. The concentration of the anesthetic was 0.25 or 1.25% generally in 10 ml of normal saline. A second PCB was administered in 54 patients at least one hour after the preceding one. Fetal heart rate (FHR) was recorded via a scalp electrode and the pattern studied 15 min before and 30 min after the injection of the anesthetic. Bradycardia was defined as a persistent deceleration exceeding 3 min and occurring within 30 min of the PCB. Variability and acceleration pattern persisted independently of the PCB. Following PCB, decelerations of all types increased, while the basal rhythm decreased by on average 1.5 beats/min. Following PCB fetal bradycardia occurred in 1.9%. The bradycardia persisted on average for 6.5 min with a lowest average FHR of 73 beats/min. Retrospectively, 6 out of 9 infants exhibited recognized risk factors for bradycardia. All infants with bradycardia scored 9-10/5 min, according to the Apgar rating scale and all had a normal development with regard to growth, motor and speech development at the age of 2 years. There were no significant differences in vaginal operative deliveries between the PCB and the non-PCB group.(ABSTRACT TRUNCATED AT 250 WORDS)