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PubMed1998

A miniaturized artificial mastoid using a skull simulator.

A miniaturized artificial mastoid of size and weight that allow calibration and measurement of bone conduction hearing aids in a conventional audiometric soundproof box has been developed. Its level of mechanical impedance corresponds to the standard IEC 373 (1990) within the frequency range 250 Hz to 8 kHz. The miniaturized artificial mastoid consists of three parts: coupler, skull simulator (TU-1000), and an external electrical correction filter. The coupler is a highly damped mass-spring system designed to give the miniaturized artificial mastoid mechanical impedance in accordance with the standard IEC 373 (1990). It was found that the miniaturized artificial mastoid yielded results that are in correspondence with results obtained with the Brüel & Kjaer type 4930 artificial mastoid for frequencies above 450 Hz. Thus, at these frequencies, the miniaturized artificial mastoid can be used for audiometer calibration as well as measurement of bone conduction hearing aids.

Bone Conduction↗
PubMed2004

Social capital, the miniaturization of community and assessment of patient satisfaction in primary healthcare: a population-based study.

AIMS: A study was undertaken to assess the impact of social participation, trust and the miniaturization of community, i.e. high social participation/low trust, on two measures of patient dissatisfaction in primary healthcare. METHODS: The Scania 2000 public-health survey is a cross-sectional, postal questionnaire study. A total of 3,456 persons aged 18-80 years who had a regular doctor within the primary healthcare system were included. A logistic regression model was used to investigate the association between the social capital variables and dissatisfaction. Multivariate analysis analysed the importance of confounders on the differences in lack of general openness and lack of information concerning treatment in accordance with social capital variables. RESULTS: Lack of openness is positively associated with low trust, the miniaturization of community and low social capital, while lack of information is not significantly associated with the miniaturization of community, but to a lesser extent with low trust and low social capital. CONCLUSIONS: Low levels of trust and the miniaturization of community may enhance non-specific patient dissatisfaction such as experience of lack of openness by the patient. In contrast, the miniaturization of community was not significantly associated with the more specific "lack of information". The results have implications for the evaluation of patient dissatisfaction.

Adolescent↗
PubMed2005

Rapid assignment of the swine major histocompatibility complex (SLA) class I and II genotypes in Clawn miniature swine using PCR-SSP and PCR-RFLP methods.

BACKGROUND: Inbred miniature swine with defined novel SLA haplotypes will be useful in allo- and xeno-transplantation studies, which can be carried out representing variable combinations of SLA haplotypes. METHODS: In Clawn miniature swine, two haplotypes (c1 and c2) and one crossover haplotype (c3) have been assigned by nucleotide sequence determination of RT-PCR products of the three SLA classical class I genes and two SLA class II genes. To select SLA class I and II homozygotes in Clawn miniature swine individuals, we developed a rapid and simple SLA-class I- and II-DNA typing method by a combination of polymerase chain reaction-sequence specific primer (PCR-SSP) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques. RESULTS: Seven allele specific primer pairs were designed for amplification of the second exons of three SLA class I genes, SLA-1, SLA-2, and SLA-3, and one SLA class II gene, DRB1. Furthermore, based on PCR-RFLP patterns in the SLA-DQB1 gene, two allelic variants were recognized in the second exon in the Clawn miniature swine. Three haplotypes, c1, c2 and c3, were simply identified by the combination of PCR-SSP and PCR-RFLP methods in 22 samples from five families. A single allele at each of the class I and II genes was also observed in seven samples as SLA class I and II homozygotes with either the c1 or c2 haplotype. CONCLUSIONS: The combination of PCR-SSP and PCR-RFLP methods facilitate the rapid identification of the three haplotypes and SLA class I and II homozygotes in individual Clawn miniature swine.

Alleles↗
PubMedDate not supplied

Inherited retinal dysplasia and persistent hyperplastic primary vitreous in Miniature Schnauzer dogs.

The objectives of this study were to define the clinical syndrome of retinal dysplasia and persistent primary vitreous in Miniature Schnauzer dogs and determine the etiology. We examined 106 Miniature Schnauzers using a biomicroscope and indirect ophthalmoscope. The anterior and posterior segments of affected dogs were photographed. Four enucleated eyes were examined using routine light microscopy and scanning electron microscopy. A pedigree was constructed and related dogs were test-bred to define the mode of inheritance of this syndrome. Congenital retinal dysplasia was confirmed in 24 of 106 related Miniature Schnauzer dogs. Physical and postmortem examinations revealed that congenital abnormalities were limited to the eyes. Biomicroscopic, indirect ophthalmoscopic, and neuro-ophthalmic examinations confirmed that some of these dogs were blind secondary to bilateral retinal dysplasia and detachment (nonattachment) (n = 13), and the remainder had generalized retinal dysplasia (n = 11). Fifteen of these dogs were also diagnosed with unilateral (n = 9) or bilateral (n = 6) persistent hyperplastic primary vitreous. Nutritional, infectious, or toxic etiologies were not evident on physical, postmortem, light microscopic, or transmitting and scanning electron microscopic examination of four affected Miniature Schnauzers. We examined the pedigree and determined that an autosomal recessive mode of inheritance was most likely. Three test-bred litters including those from affected parents, carrier and affected parents, and carrier parents confirmed this mode of inheritance. This study confirms that retinal dysplasia and persistent hyperplastic primary vitreous is a congenital abnormality that is inherited as an autosomal recessive condition in Miniature Schnauzers.

Animals↗
PubMed1993

Intraoperative echocardiography by a new miniaturized epicardial probe: preliminary findings.

Miniaturized probes constitute recent progress in the field of epicardial echocardiography. We recently used a new miniaturized probe, derived from a standard transesophageal probe, in a series of 12 adult patients who underwent cardiac surgery in order to test the possibility of obtaining new views for epicardial imaging. This study demonstrates the feasibility and safety of performing intraoperative echocardiography when using a miniaturized epicardial probe. This probe may be placed on a broader epicardial and vascular area, thus overcoming the size limitations of the commonly used epicardial probes. The major limitation found with the miniaturized probe, however, was the inability to obtain a true four-chamber view from the ventricular apex, due to the difficulty of holding the probe motionless between the apex and the diaphragm while the heart is beating. Although extensive experience with larger groups of patients and different pathologies will be required to define the full potential of this new probe, the advent of the miniaturized probe may further expand the applicability of epicardial echocardiography in pediatric patients during surgery for congenital heart disease.

Adolescent↗
PubMed1990

Characteristics of miniature inhibitory postsynaptic currents in CA1 pyramidal neurones of rat hippocampus.

1. Recordings were made in vitro from chloride-loaded CA1 rat hippocampal pyramidal neurones in the presence of tetrodotoxin (TTX) to examine miniature inhibitory postsynaptic currents (IPSCs). 2. Most spontaneous synaptic events recorded before TTX was applied, and all events that were resolved in the presence of TTX, were blocked by the GABAA receptor antagonist bicuculline. 3. At 25 degrees C, averaged miniature IPSCs had time to peak of about 3 ms and in most cases decayed with a single time constant close to 25 ms. 4. With a driving force for chloride ions between 70 and 80 mV, the mean miniature IPSC amplitude was 19.6-27.9 pA, yielding a conductance of 258-326 pS. The mean amplitude of unitary IPSCs recorded before TTX was applied was in the range of 31-73 pA. 5. When intervals between miniature IPSCs were compared with an exponential distribution, there was an excess of events at intervals shorter than 5 ms. Some individual events appeared to represent the nearly simultaneous release of two inhibitory quanta. 6. Miniature IPSC amplitude distributions were better fitted with the sum of two Gaussians than with one Gaussian. The variance in amplitude of a single quantal event exceeded that of the baseline noise. 7. Comparison of the conductance changes corresponding to the first Gaussian distribution with single GABA channel data suggests that one inhibitory quantum opens twelve to twenty chloride channels and that GABA molecules bind once to a postsynaptic receptor.

Animals↗
PubMed1998

Facilitation of miniature GABAergic currents by ruthenium red in neonatal rat hippocampal neurons.

The whole cell configuration of the patch-clamp technique was used to study the modulation gamma-aminobutyric acid (GABA)-mediated postsynaptic currents by ruthenium red in CA3 hippocampal neurons in slices obtained from postnatal (P) days P6-P10 old rats. In the presence of kynurenic acid (1 mM), ruthenium red (100 microM) completely blocked stimulus-elicited GABA-mediated postsynaptic currents and reduced by 50% the amplitude of the spontaneous ones. Ruthenium red (100 microM) increased the frequency but not the amplitude of miniature GABAergic currents recorded in the presence of tetrodotoxin (1 microM) and kynurenic acid (1 mM), an effect that was prevented by heparin (100 microM). Ruthenium red did not modify the kinetics of miniature postsynaptic currents and the currents induced by exogenous application of GABA (10 microM) in the presence of tetrodotoxin, suggesting that its action was presynaptic in origin. The effects of ruthenium red on quantal GABA release was independent of external calcium. In a nominally Ca2+-free solution the potentiating effect induced by this polyvalent cation on miniature postsynaptic currents was still present. Intracellular calcium stores were not involved in ruthenium red action, because this polyvalent cation was able to facilitate miniature currents also in the presence of thapsigargin (10-20 microM). These results indicate that ruthenium red has a dual action on GABA release from GABAergic interneurons: it reduces the amplitude of spontaneous events and increases the frequency of miniature currents. The former effect is calcium-dependent, whereas the latter is calcium independent.

Animals↗
PubMed1995

Brain size and morphology in miniaturized plethodontid salamanders.

In six miniaturized salamanders of the family Plethodontidae, including one of the smallest tetrapod vertebrates. Thorius pennatulus, the anatomical consequences of miniaturization for the brain were investigated. We determined (1) absolute and relative size of the brain, major parts of the brain, the tectum and tectal gray matter, (2) nerve cell size and density, and (3) the number of cells within the visual and visuomotor centers (thalamus, tectum/praetectum and tegmentum). No common compensatory strategy for the brain among the miniaturized salamanders was found. Except for the smallest species, T. pennatulus, only some of the expected compensatory processes (increase in relative size of the brain, relative size of visual centers, relative amount of gray matter or relative density of cell packing density) are found in any species, and these occur in different combinations and degrees. The most decisive factor for maximizing cell number was cell size. Miniaturized species with small cells also have many visual cells, regardless of the other factors. In contrast, the minimum number of visual neurons is found in miniaturized salamanders with large cells. It is concluded that the neuroanatomical traits investigated exert different degrees of resistance to adaptive compensatory processes. Cell size seems to be the most resistant parameter and is strictly dependent on genome size.

Animals↗
PubMed1982

Effects of acetylcholine on the tone and miniature contractions of isolated dog urinary bladder.

Effects of acetylcholine on the tone and miniature contractions of dog urinary bladder were investigated in vitro. In both dome and trigone preparations, cumulative administrations of acetylcholine produced dose-dependent increases in the tone, which were dose-dependently depressed by prior administration of atropine and augmented by neostigmine. The frequency of miniature contractions in the dome and trigone was dose-dependently increased by acetylcholine. The dose-response curves of the frequency for acetylcholine were shifted to the right by atropine and to the left by neostigmine in both preparations. The amplitude of miniature contractions in both preparations was not significantly changed by acetylcholine. A computer analysis showed that changes in the tone of the bladder had the positive correlation to the frequency of miniature contractions. The results indicate that acetylcholine would act on the urinary bladder through activation of muscarinic receptors, and that there is the positive correlation between changes in the tone and the frequency of miniature contractions.

Acetylcholine↗
PubMed2001

Calcification of the intervertebral discs and curvature of the radius and ulna: a radiographic survey of Finnish miniature dachshunds.

The vertebral column of 124 randomly selected miniature dachshunds, representing 4.5% of the population registered by the Finnish Kennel Club during the years 1988 to 1996, were radiographed. The front legs were also radiographed in order to evaluate the curvature of the radius and ulna. Calcified discs were found in 75.9% of the longhaired miniature dachshunds and in 86.7% of the wirehaired ones. The occurrence of signs associated with IDD was 16.5% in longhaired and 15.6% in wirehaired miniature dachshunds. The occurrence of signs of IDD in dogs with calcified discs was 20.0% and 17.9% in longhaired and wirehaired miniature dachshunds, respectively. In dogs without calcifications only one dog showed signs of IDD. The curvature of the radius and the ulna did not differ between the dogs with signs of IDD and the healthy ones, or between the dogs with and without intervertebral calcifications. Our results indicate that radiographic eradication based on the presence of intervertebral calcifications is not suitable for breeding purposes for the Finnish miniature dachshund population because the percentage of dogs without calcifications is small.

Animals↗
PubMed2006

Miniature synaptic events elicited by presynaptic Ca2+ rise are selectively suppressed by cannabinoid receptor activation in cerebellar Purkinje cells.

Activation of cannabinoid receptors suppresses neurotransmitter release in various brain regions. In cerebellar Purkinje cells (PCs), cannabinoid agonists suppress both EPSC and IPSC evoked by stimulating the corresponding inputs. However, cannabinoid agonists suppress miniature IPSC (mIPSC) but not miniature EPSC (mEPSC) at normal external Ca2+ concentration ([Ca2+]o). Therefore, cannabinoid agonists are thought to suppress release machinery for IPSCs but not that for EPSCs. Here we investigated the possible cause of this difference and found that cannabinoid agonists selectively suppressed Ca2+-enhanced miniature events. A cannabinoid agonist, WIN55,212-2 (5 microM), did not affect mEPSC frequency with 2 mM extracellular Ca2+ (Ca2+(o)). However, WIN55,212-2 became effective when mEPSC frequency was enhanced by elevation of presynaptic Ca2+ level by perfusion with 5 mM Ca2+(o) or bath application of A23187, a Ca2+ ionophore. In contrast, WIN55,212-2 suppressed mIPSC frequency with 2 mM Ca2+(o), but it became ineffective when the presynaptic Ca2+ level was lowered by perfusion with a Ca2+-free solution containing BAPTA-AM. Experiments with systematic [Ca2+]o changes revealed that mIPSC but not mEPSC regularly involved events elicited by presynaptic Ca2+ rise with 2 mM Ca2+(o). Importantly, Ca2+-enhancement of mEPSC and mIPSC was not attributable to activation of voltage-dependent Ca2+ channels. Activation of GABAB receptor or group III metabotropic glutamate receptor, which couple to G(i/o)-protein, also preferentially suppressed Ca2+-enhanced miniature events in PCs. These results suggest that the occurrence of Ca2+-enhanced miniature events at normal [Ca2+]o determines the sensitivity to the presynaptic depression mediated by cannabinoid receptors and other G(i/o)-coupled receptors in PCs.

Animals↗
PubMed2003

Assessment of corneal thickness, intraocular pressure, optical corneal diameter, and axial globe dimensions in Miniature Horses.

OBJECTIVE: To determine corneal thickness, intraocular pressure (IOP), and horizontal and vertical corneal diameter (HCD and VCD) and to obtain axial measurements of the anterior chamber depth (ACD), crystalline lens thickness (CLT), vitreous chamber depth (VtCD), and axial globe length (AGL) in eyes of Miniature Horses. ANIMALS: 41 healthy Miniature Horses. PROCEDURE: Ocular component measurements were obtained via ultrasonic pachymetry, applanation tonometry, ultrasound, and by use of a Jameson caliper. RESULTS: Mean IOP and corneal thickness for all eyes were 26.0 mm Hg and 785.6 microm, respectively. There was no correlation of age with IOP or corneal thickness and no difference in these variables between right and left eyes or between females and males. Mean HCD andVCD were 25.8 and 19.4 mm, respectively; although there were no differences between sexes or between right and left eyes, there was positive correlation of optical corneal diameters with increasing age. Mean ACD, CLT, VtCD, and AGL were smaller in Miniature Horses (5.6, 10.0, 18.1, and 33.7 mm, respectively), compared with values for full-sized horses; there was no difference in these variables between sexes or between right and left eyes in Miniature Horses, but they were correlated with increasing age. CONCLUSIONS AND CLINICAL RELEVANCE: In Miniature Horses, corneal thickness and IOP are similar to values reported for full-sized horses and do not increase with advancing age. Vertical corneal diameter, HCD, and AGL increase until 5, 7, and 2 years of age, respectively.

Aging↗
PubMed2006

[Genetic diversity of seven miniature pig breeds (strains) analyzed by using microsatellite markers].

Twenty-seven microsatellite markers recommended by the Food and Agriculture Organization (FAO) and the International Society for Animal Genetics (ISAG) were used to analyze the genetic diversities of 7 Chinese native miniature pig breeds/strains (Jiuyang Xiang Pig, Jianbai Xiang Pig, Congjiang Xiang Pig, Huanjiang Xiang Pig, Black Xiang Pig, Wuzhishan Pig, and Diannan Small Ear Pig) and 3 western pig breeds (Duroc, Large White, and Landrace). The results indicate that there exists, in general, a high degree of genetic variability within the 7 miniature pig breeds. However, the genetic variability in Jiuyang Xiang Pig, Jianbai Xiang Pig, Huanjiang Xiang Pig, and Congjiang Xiang Pig (average PICs being 0.61-0.64) was significantly lower than that in the other three miniature pig breeds (average PICs being 0.60-0.84). The genetic divergence among Jiuyang, Jianbai, Huanjiang, and Congjiang was very small (Nei's standard genetic distances being 0.12-0.22), but it was large between them and the other three miniature pig breeds (Nei's standard genetic distances being 1.61-1.96), and even larger between them and the three foreign breeds (Nei's standard genetic distances being 1.99-3.30). Cluster analysis reveals three obvious clusters for the 10 breeds: Jiuyang, Jianbai, Huanjiang, and Congjiang are in one cluster, the other three miniature pig breeds in the other, and the three foreign breeds in the third. These results are consistent with the geography distribution and origin of these breeds.

Animals↗
PubMed2000

Identification and characterization of the miniature pig Huntington's disease gene homolog: evidence for conservation and polymorphism in the CAG triplet repeat.

Huntington's disease (HD) is associated with a significant expansion of a CAG trinucleotide repeat, which results in a lengthened polyglutamine tract in the single gene product, huntingtin, on human 4p16.3. We isolated cDNA clones that encompassed the entire coding sequence of the miniature pig HD gene (Sus HD) from two porcine testis cDNA libraries. The cDNA contig revealed a 12,749-nucleotide transcript coding for a 345-kDa protein (3139 amino acid residues), which exhibited 96% peptide sequence homology to human huntingtin. Northern blot analysis revealed that the Sus HD gene was ubiquitously expressed as two large transcripts of approximately 11 and 13 kb in size in all the tested tissues, much like the human HD gene. The CAG trinucleotide repeat was found to be interrupted by CAA triplets and to encode 17 or 18 consecutive glutamine residues. In our laboratory stock of miniature pig, three allotypes in the triplet repeat sequence were found. Thus, the Sus HD gene closely resembles its human counterpart in terms of sequence and expression pattern. In particular, human-miniature pig similarities in the normal length of the CAG triplet repeat as well as its repeat-number polymorphism may indicate that miniature pig would provide a good animal model for Huntington's disease.

3' Untranslated Regions↗
PubMed2004

Low-severity metacarpal and phalangeal fractures treated with miniature plates and screws.

INTRODUCTION: The results reported in the literature of metacarpal and phalangeal fractures treated with miniature plates and screws are scarce and contradictory. The aim of our study was to evaluate the functional results after low-severity metacarpal and phalangeal fractures treated by miniature plates and screws. MATERIALS AND METHODS: We retrospectively reviewed 44 patients of a consecutive series with 56 low-severity metacarpal and/or phalangeal fractures stabilized with miniature plates and screws with a mean follow-up of 24 months to assess objective and subjective outcomes and complications. The objective assessment included measurement of the range of motion (ROM) of the involved finger, prehension, sensory function and strength. The subjective evaluation assessed the impairment and pain felt by the patient. RESULTS: At the final check-up, average total active movement of the involved digit was 256 degrees (range 175 degrees -260 degrees ), and average score for prehension was 49.3 (range 30-50), with 41 patients with a full score. The Jamar test pointed to a significant reduction in grip strength (-5.2%) of the injured hand compared with the other hand. Average subjective impairment score for all the fractures was 15.5 (range 10-16), with 39 patients having a score between 16 and 14 (no impairment). Fracture reduction was anatomic in 42 fractures (75%), satisfactory in 11 (19.6%) and unsatisfactory in 3 (5.4%). There were no contractures, non-unions, infections or tendon ruptures. Twenty patients (45%) presented with one or more complications in 23 fractures (41.1%). CONCLUSION: These very favourable results suggest that miniature plates and screws are a possible choice in the treatment of these fractures.

Adolescent↗
PubMed2005

Miniature robots can assist in laparoscopic cholecystectomy.

Laparoscopy reduces patient trauma but eliminates the surgeon's ability to directly view and touch the surgical environment. Although current robot-assisted laparoscopy improves the surgeon's ability to manipulate and visualize the target organs, the instruments and cameras remain constrained by the entry incision. This limits tool tip orientation and optimal camera placement. This article focuses on developing miniature in vivo robots to assist surgeons during laparoscopic surgery by providing an enhanced field of view from multiple angles and dexterous manipulators not constrained by the abdominal wall fulcrum effect. Miniature camera robots were inserted through a small incision into the insufflated abdominal cavity of an anesthetized pig. Trocar insertion and other laparoscopic tool placements were then viewed with these robotic cameras. The miniature robots provided additional camera angles that improved surgical visualization during a cholecystectomy. These successful prototype trials have demonstrated that miniature in vivo robots can provide surgeons with additional visual information that can increase procedural safety.

Animals↗
PubMed2005

Miniaturization of absorbance assays using the fluorescent properties of white microplates.

Miniaturization of high-throughput screening (HTS) assays has several obvious advantages, including increased throughput and lower cost by reduction in reagent consumption. Although absorbance assays are widely used in research laboratories, their application for HTS in a low-volume format has been met with mixed success because they are difficult to miniaturize. Challenges for the miniaturization of absorbance assays include low signal due to short path lengths and meniscus distortions in small well sizes. Here we describe a method to miniaturize absorbance assays to standard, white, low-volume 384-well and 1536-well microplates using a fluorometric plate reader for detection. The premise of this absorbance assay is based on the fluorescent properties of white microplates and the ability of a colored product to quench the fluorescence signal from the plate by absorbing either the excitation light or the emission light. This method was applied to the detection of inorganic phosphate using Quinaldine red and Malachite green dyes and to the monitoring of alkaline phosphatase hydrolysis of p-nitrophenyl phosphate. These assays can be carried out in low volumes, give robust screening statistics, and can be accomplished with a simple, inexpensive fluorometric plate reader.

Combinatorial Chemistry Techniques↗
PubMed2005

Miniaturized thermal lens and fluorescence detection system for microchemical chips.

We have developed a miniaturized two-way detection system using thermal lens and fluorescence spectroscopies for microchip chemistry. The system was composed of laser diode (LD) modules, fiber-based optics combined with a gradient index lens, and miniaturized detection units for thermal lens and fluorescence signals. The detection limits in the thermal lens and fluorescence spectroscopies were 6.3 x 10(-9)M for Ni(II) phthalocyanine tetrasulfonic acid and 3.0 x 10(-9)M for cy5, respectively. The performance of the system with the miniaturized thermal lens was equivalent to that of a conventional thermal lens microscope. The fluorescence sensitivity was comparable to sensitivities offered by conventional miniaturized systems.

Miniaturization↗