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Biomedical subjects

H Mikola

Publications and source records attributed to H Mikola.

At least 19 recordsLinked to original sources
PubMed2001

The balance of the autonomic nervous system is normal in colicky infants.

UNLABELLED: Excessively crying, hard-to-soothe infants are described as colicky. The self-limiting course of infantile colic during early infancy suggests an etiology of transient developmental dysmaturation. It has been proposed that emotional characteristics such as temperament and self-soothing ability are correlated with the balance of the autonomic nervous system. Heart rate variability (HRV) analysis was used for evaluating the balance of the autonomic nervous system in colicky and control infants during and after the colicky period. HRV analysis was carried out on 12 colicky infants and 14 control infants at the age of 2 mo, and repeated on 10 colicky and 11 normal infants at the age of 7 mo. Measurements were performed during polygraphically confirmed slow-wave sleep (sleep stages 3 and 4). Three HRV frequency bands were defined, including a high (0.2-1.0 Hz), middle (0.12-0.2 Hz) and low (0.025-0.12 Hz) frequency variability. There were no differences between the study groups in any of the three HRV frequency bands analyzed. The high frequency variability increased significantly with age in both study groups (p = 0.009). CONCLUSION: The findings suggest that imbalance between the parasympathetic and the sympathetic nervous system is not associated with infantile colic and that, in accordance with previous findings, control of HRV shifts in a parasympathetic direction with increasing age during the first year of life.

Autonomic Nervous System↗
PubMed2000

Production and characterisation of monoclonal antibodies against a very small hapten, 3-methylindole.

Monoclonal antibodies were produced against a very small (131.2 Da) hapten, 3-methylindole. Nine derivatives of 3-methylindole were synthesised with spacers ending in a carboxyl group, and coupled to immunogenic carriers and europium chelate labels. Almost all the antigens elicited an antihapten response, but the majority of the mAbs produced strongly recognised the spacer group and did not bind free 3-methylindole. However, specific antibodies were obtained with five immunogens. Specificity could be directed against the pyrrole ring by locating the bridging group to the aromatic moiety of the indole ring system. Any modification in the position 3 of the indole ring strongly hindered mAb binding to the compound, and the cross-reactivity of physiologically important compounds, such as tryptophan and tryptamine, was negligible for all of the mAbs. The developed hapten structures successfully focused antibody recognition to the important sub-determinants in the indole ring system. Similar constructs could also be useful in the development of antibodies against other indolic compounds.

Antibodies, Monoclonal↗
PubMed2000

Time-resolved fluoroimmunoassay of plasma daidzein and genistein.

We present a method for the determination of the phytoestrogens daidzein and genistein in plasma (serum). These weakly estrogenic isoflavones occur in soybeans and in smaller amounts in some other beans and plants. It has been suggested that they may afford protection against prostate and breast cancer. The method is based on time-resolved fluoroimmunoassay (TR-FIA) using a europium chelate as a label. After synthesis of 4'-O-carboxymethyl-daidzein and 4'-O-carboxymethyl-genistein the compounds are coupled to bovine serum albumin (BSA), then used as antigens to immunize rabbits. The tracers with the europium chelate are synthesized using the same 4'-O-derivative of the isoflavones. After enzymatic hydrolysis and ether extraction the immunoassay is carried out using the VICTOR 1420 multilabel counter (Wallac Oy, Turku, Finland). The antisera cross-reacted to some extent with some isoflavonoids but not with flavonoids. The cross-reactivity seems not to influence the results, which were highly specific for both compounds. The correlation coefficients between the TR-FIA methods and the reference method based on isotope dilution gas chromatography-mass spectrometry were high; r-values were about 0.95-0.99 depending on concentration. The intra-assay coefficients of variation (CV%) for daidzein and genistein at three different concentrations vary 3.2-4.5 and 3.2-4.1, respectively. The inter-assay CVs vary 5.0-6.3 and 4.5-5.3, respectively. The working ranges of the daidzein and genistein assays are 1.0-216 and 1.7-370 nmol/l, respectively. The plasma values (n = 80) of daidzein and genistein are very low in Finnish subjects (mean for daidzein, 3.8+/-6.8 and for genistein, 3.2+/-7.6 nmol/l; median value for daidzein 1.5 and for genistein 1.4 nmol/l).

Animals↗
PubMed2000

Rapid analysis of phytoestrogens in human urine by time-resolved fluoroimmunoassay.

A time-resolved fluoroimmunoassay (TR-FIA), with europium labeled phytoestrogens as tracers, was developed for the quantitative determination of enterolactone, genistein and daidzein in human urine. The aim was to create a method for the screening of large populations in order to assess the possible correlations between the urinary levels and the risk of Western diseases. After the synthesis of the 5'-carboxymethoxy derivative of enterolactone and 4'-O-carboxymethyl derivatives of daidzein and genistein, the respective compound was coupled to bovine serum albumin and then used as an antigen in the immunization of rabbits. The same derivatives of the phytoestrogen were used in preparing the europium tracers. After the enzymatic hydrolysis, the TR-FIA was carried out using the Victor 1420 multilabel counter. The method has sufficient sensitivity to measure the phytoestrogens at concentrations even below 5 nmol/l. The intra- and inter-assay coefficients of variation, at three different concentrations, varied from 1.9 to 5.3 and from 2.4 to 9.7, respectively. We measured urinary enterolactone, genistein and daidzein in 215 samples from Finnish healthy women and found that more than 50% of the values ranged between 1 and 7, <0.1 and 0.6 and below 0.6 micromol/24 h, respectively. The TR-FIA method including only a hydrolysis step gave higher values than those measured by gas chromatography-mass spectrometry (GC-MS). However, the assay results by the present method showed strong correlation with those obtained by GC-MS. It is concluded that the TR-FIA is suitable for population screening of urinary phytoestrogens.

4-Butyrolactone↗
PubMed1998

Time-resolved fluoroimmunoassay for plasma enterolactone.

We present a method for the determination of the lignan enterolactone in plasma (serum). This compound, produced by intestinal bacteria from matairesinol and secoisolariciresinol in fiber-rich food, is a biomarker related to the intake of a healthy diet. The method is based on time-resolved fluoroimmunoassay using a europium chelate as a label. After synthesis of 5'-O-carboxymethoxyenterolactone the compound is coupled to bovine serum albumin and then used as antigen in immunization of rabbits. The tracer with the europium chelate is synthesized using the same 5'-derivative of enterolactone. After enzymatic hydrolysis and ether extraction the immunoassay is carried out using the VICTOR 1420 multilabel counter (Wallac Oy, Turku, Finland). No antiserum cross-reactivity with available lignans, isoflavonoids, or flavonoids could be detected. The intraassay and interassay coefficients of variation at different concentrations vary 4.6-6.0 and 5.5-9.9, respectively. The working range of the assay is 1.5-540 nmol/liter. We measured enterolactone in serum/plasma of 224 Finnish subjects: 98.8% of the subjects had values <100 nmol/liter, 38.0% had 20-39.9 nmol/liter, and 34.4% had <20 nmol/liter.

4-Butyrolactone↗
PubMed1996

CT, MRI, and PET in a case of intractable epilepsy.

We report the case of a child with drug-refractory partial epilepsy in whom computed tomography showed no abnormality and magnetic resonance imaging showed a noninvasive cystic lesion in the left hippocampus. The finding in the positron emission tomography study with L-[methyl-11C]-methionine as a tracer suggested a tumor. This finding was confirmed histologically.

Brain Neoplasms↗
PubMed1996

Sleep in multiple pregnancy: breathing patterns, oxygenation, and periodic leg movements.

OBJECTIVES: Our goal was to study whether multiple pregnancy at the third trimester predisposes to breathing disturbances and arterial oxyhemoglobin desaturation during sleep. STUDY DESIGN: Nocturnal breathing, oxygenation, and movement activity were studied in 10 mothers: 8 with twins, 1 with triplets, and 1 with quadruplets. RESULTS: No obstructive and few central sleep apnea episodes were observed. Four subjects had episodes of increased respiratory resistance, but only one, the mother with quadruplets, was significantly affected. Arterial oxyhemoglobin saturation was always maintained above 90%. Periodic leg movements were present in all mothers, with a frequency range of 3.7 to 49.7 movements per hour. CONCLUSIONS: In spite of the large uterus in multiple pregnancy, nocturnal breathing and oxygenation are well maintained. Increased motor activity and frequent awakenings suggest poor sleep quality, which may be further compromised by intensive periodic leg movements.

Adult↗
PubMed1996

In vitro establishment of lytic and nonproductive infection by herpes simplex virus type 1 in three-dimensional keratinocyte culture.

The F strain of herpes simplex virus type 1 (HSV-1) was tested for its ability to produce lytic or nonproductive infection in squamous epithelial cells cultured in a three-dimensional organotypic tissue culture. For the tissue culture, we used HaCat cells (immortalized skin keratinocytes) and normal fibroblasts derived from the skin. The cultures were infected with HSV-1 (5 PFU) either when the epithelial cells had grown as a monolayer with a confluence of 80% on the collagen fibroblast gel or 30 min after lifting of the epithelial cells into the air-liquid interface. The cultures were collected 1 week after inoculation. Typical cytopathic effects of HSV infection (ballooning and reticular degeneration with multinucleate giant cells) were seen only in those cultures in which the epithelial cells were infected before lifting. The presence of HSV was confirmed by DNA and RNA in situ hybridization and PCR. No morphological changes were found in cultures infected after lifting into the air-liquid interface. No infectious virus was recovered either from cells or culture supernatant. However, these cultures were positive for HSV DNA on PCR and showed expression of the LAT gene by in situ hybridization and Northern blot (RNA) hybridization. The present results indicate that both nonproductive and lytic HSV infection can be produced in vitro and the outcome of the infection depends on the time of viral inoculation in relation to epithelial maturation.

Animals↗
PubMed1995

Inhibition of herpes simplex virus type 1, respiratory syncytial virus and echovirus type 11 by peroxidase-generated hypothiocyanite.

The human mouth is an important route of viral transmission and evidence exists that human saliva can neutralize some viruses, e.g. herpes simplex type 1 (HSV-1) and human immunodeficiency virus (HIV) in vitro. However, little is known of the actual antiviral agents in saliva. We have analyzed how hypothiocyanite (HOSCN/-OSCN) ions, present in human saliva and generated by salivary peroxidase systems, affect the viability of three different types of viruses; HSV-1 (capable of inducing oral lesions), respiratory syncytial virus (RSV, respiratory infections), and echovirus 11 (EV 11, enteric diseases). Viral suspensions were pretreated (30 min) with HOSCN/-OSCN concentrations up to 180 microM both at pH 6.0 and 7.1 and inoculated into human gingival fibroblasts. The cultures were incubated at 37 degrees C for 18-48 h, fixed and the infected cells were counted after immunoperoxidase staining. HSV-1 was most sensitive to HOSCN/-OSCN with an IC50 of 8.5 microM at pH 6.0 and an IC50 of 20 microM at pH 7.1, respectively. RSV was inhibited by HOSCN/-OSCN only at pH 6.0 with an IC50 of 8.0 microM. EV 11 was also resistant at neutral pH, but sensitive at pH 6.0 with an IC50 of 68 microM. In contrast to HSV-1 and RSV, the inhibition of EV 11 was not dependent on the concentration of HOSCN/-OSCN. The inhibition was in all cases stronger at pH 6.0 than at neutral pH. Our results suggest that hypothiocyanite, a normal component of human whole saliva, in physiological concentrations effectively inhibits HSV-1 and RSV at acidic pH, whereas EV 11 is more resistant in vitro.

Adult↗
PubMed1994

Syntheses of europium-labeled digoxin derivatives and their use in time-resolved fluoroimmunoassay.

A simple and efficient method of derivatizing and labeling the terminal sugar ring of digoxin (and other steroid glycosides) is described. The terminal sugar ring was oxidized by periodate to dialdehyde, followed by a reaction with the aminooxy group of heterobifunctional spacer reagent. Usually, reductive amination is needed to stabilize the Schiff base-type compounds produced in reactions between amino and aldehyde groups. Here the oxime compounds produced are stable wherefore the reductive amination step can be avoided and the reaction gives high yields without significant side reactions. After characterization the digoxin dioxime derivatives formed were labeled with europium chelates. These labeled digoxin derivatives bearing one or two europium-containing chelates, coupled via different spacers, were purified and tested in a competitive time-resolved fluoroimmunoassay. Several digoxin-specific monoclonal antibodies were also tested to determine the most suitable antibody-tracer combination, which was then employed to develop a simple competitive time-resolved fluoroimmunoassay for digoxin.

Aldehydes↗
PubMed1993

Labeling of estradiol and testosterone alkyloxime derivatives with a europium chelate for time-resolved fluoroimmunoassays.

O-Carboxymethyl, O-(4aminobutyl)-, and O-(6-aminohexyl)-oximes of 6-oxoestradiol and testosterone were labeled using a described general labeling method with a europium chelate. A stable amide or thiourea bond was formed between the europium label and carboxyl or amino derivative of the steroid, respectively. These labeled "tracers" were purified and briefly tested in a competitive time-resolved fluoroimmunoassay using monoclonal antibodies raised against O-(carboxymethyloxime)-bovine serum albumin derivatives of estradiol and testosterone. Only buffer-based standards were used in a model system for the testing. These studies indicate only minor functional differences while using these antibodies due to the length of the spacer arm, and a higher sensitivity in the clinically relevant standard range was reached with the longer spacers.

Antibodies, Monoclonal↗
PubMed1993

Effects of a lactoperoxidase system-containing toothpaste on levels of hypothiocyanite and bacteria in saliva.

Lactoperoxidase (LPO)/H2O2/SCN(-)-system-generated hypothiocyanite ions (OSCN-) and hypothiocyanous acid (HOSCN) are inhibitory against a number of oral bacteria, including mutans streptococci. A commercially available toothpaste (Biotene) comprises the complete LPO system. Generation of HOSCN/OSCN- by Biotene was studied in vitro both in sterilized and nonsterilized saliva of 10 healthy subjects. The HOSCN/OSCN- yield ranged from 100 to 300 microM with Biotene, while the salivary levels of HOSCN/OSCN- before the addition of Biotene were 30.1 +/- 25.1 microM. Two in vivo trials were carried out. In the first study, resting saliva was collected from 12 individuals before, immediately after, and 2, 5, 10 and 20 min after brushing with Biotene to evaluate the in vivo generation and decomposition of HOSCN/OSCN-. In the second study, 26 healthy individuals attended a 1-month crossover trial with Biotene and a control toothpaste, Vademecum (no LPO system), both containing F- and xylitol. The salivary counts of total streptococci, mutans streptococci (MS), lactobacilli and the total flora (TF), as well as the peroxidase, thiocyanate ion and HOSCN/OSCN- levels were determined before and after 2 and 4 weeks daily use of the toothpastes. Twice-a-day use of Biotene for 1 month resulted in an elevation of 'resting levels' of HOSCN/OSCN-. No such effect was found with the control toothpaste. No significant changes were found in the salivary levels of total streptococci, MS, lactobacilli or TF after 1-month use of either toothpaste. The results show the capability of the LPO-system-containing toothpaste to elevate the salivary levels of HOSCN/OSCN-, although no bactericidal effect was observed.

Colony Count, Microbial↗
PubMed1992

Simultaneous quadruple-label fluorometric immunoassay of thyroid-stimulating hormone, 17 alpha-hydroxyprogesterone, immunoreactive trypsin, and creatine kinase MM isoenzyme in dried blood spots.

We describe a quadruple-label fluorometric immunoassay for simultaneously measuring four analytes: thyroid-stimulating hormone (TSH), 17 alpha-hydroxyprogesterone (17 alpha-OHP), immunoreactive trypsin (IRT), and creatine kinase MM (CK-MM). The assay is based on immunoreagents labeled with four different lanthanide ions (Eu3+, Tb3+, Sm3+, and Dy3+), on dissociative fluorescence enhancement applying the principle of co-fluorescence, and on time-resolved fluorometry. The monoclonal anti-alpha-TSH and anti-IRT antibodies and the polyclonal anti-CK-MM antibody were labeled with Eu3+, Sm3+, and Dy3+, respectively; 17 alpha-OHP was labeled with Tb3+. The assay was performed in microtitration strip wells coated with a mixture of monoclonal antibodies against beta-TSH, IRT, and CK-MM and a polyclonal goat anti-rabbit IgG for capture of the rabbit anti-17 alpha-OHP antibodies. After completion of the immunoreactions, the bound fractions of the lanthanides were dissociated into the co-fluorescence enhancement solution, creating highly fluorescent chelates. The four lanthanide-specific signals were subsequently measured in a time-resolved fluorometer. The detection limits of the assay were 0.1 mIU/L for TSH, 2 nmol/L for 17 alpha-OHP, 2 micrograms/L for IRT, and 4 U/L for CK-MM.

17-alpha-Hydroxyprogesterone↗
PubMed1991

Preparation of europium-labeled derivatives of cortisol for time-resolved fluoroimmunoassays.

Cortisol 3-(O-carboxymethyl)oxime, 6- and 21-hemisuccinoxycortisol, and cortisol 7-carboxyethyl thio-ether were synthesized. These carboxyl derivatives were labeled using a described general labeling method with a europium chelate. The labeled steroids were tested in a competitive time-resolved fluoroimmunoassay using antibodies raised against cortisol. Only the site-homologous antigen-antibody pairs underwent immunoreaction and gave satisfactory calibration curves.

Europium↗
PubMed1990

SCSB method compared to EEG-based polygraphy in sleep state scoring of newborn infants.

Knowledge of the sleep state is important in physiological studies since many physiological variables show different properties in different sleep states. The recently developed static charge sensitive bed (SCSB) method allows long-term recordings of body movements, respiration and ballistocardiogram without electrodes attached to the subject. The recordings are easy to carry out and they do not disturb the subject in any way. The recorded variables are basic characteristics of different sleep states. SCSB-recordings and electroencephalography (EEG) based polygraphy as well as blind sleep state scoring were carried out in 8 newborn infants. The positive correlation between SCSB-scoring and EEG-based polygraphy scored by two clinical neurophysiologists was 68.1 and 64.1%. Only in 2% of all epochs was active sleep scored as quiet sleep or vice versa. The results indicate the usefulness of the SCSB method in sleep state scoring of newborn infants.

Ballistocardiography↗
PubMed1989

The synthesis and use of activated N-benzyl derivatives of diethylenetriaminetetraacetic acids: alternative reagents for labeling of antibodies with metal ions.

A series of bifunctional chelating agents--substituted benzyl derivatives of diethylenetriaminetetra acids--was synthesized. These agents were used to label antibodies with a lanthanide, Eu3+. The stabilities of their antibody conjugates were evaluated under different conditions and the dissociation rates of Eu3+ were measured at pH 3.2, which is used for fluorescence enhancement in time-resolved fluoroimmunoassays. The synthesized complexing agents were also compared to other reagents used for metal labelings, to diethylenetriaminepentaacetic acid-dianhydride, and to p-isothiocyanatophenyl-EDTA. The asymmetric p-isothiocyanatobenzyl derivative of diethylenetriaminetetraacetic acid-Eu3+ showed reasonably good stability at neutral pH but released Eu3+ rapidly in the acidic fluorescence enhancement solution. This makes it an optimal choice for chelate labeling in dissociation-based time-resolved fluoroimmunoassays.

Animals↗
PubMed1989

The development of non-separation time-resolved fluoroimmunoassays for the measurement of urinary metabolites.

We describe the principles of a new generation of sequential or simultaneous time-resolved fluoroimmunoassays, namely, simple, rapid, liquid-phase non-separation procedures which may be applied to the measurement of urinary steroid and drug metabolites. As an example, a method for the measurement of estrone-3-glucuronide in undiluted urine is reported. This method has a similar sensitivity, specificity and accuracy to a conventional separation fluoroimmunoassay or radioimmunoassay but in terms of speed, convenience, precision, reliability and clinical utility the new method has many advantages. The labelled antigen is a novel fluorescent europium chelate covalently linked to estrone-3-glucuronide. The antibody-binding reaction involves the incubation of the labelled antigen (2ng) with a limited concentration of polyclonal or monoclonal antibodies to estrone-3-glucuronyl-6-BSA and an aliquot of standard or sample (undiluted urine; 10 microliters) in microtitre wells. After a 10 min incubation, the fluorescence which emanates from the antibody-free label is measured in a time-resolved fluorometer and is proportional to the concentration of estrone-3-glucuronide in the standard or sample. The method may be applied for the monitoring of ovarian function in women.

Estrone↗