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At least 19 recordsLinked to original sources
PubMed1992

Isolated or phagocytosed miniature dyskeratotic cells in papilloma virus infection associated with cervical neoplasia.

Dyskeratotic cells that occur in squamous cervical epithelium under certain abnormal conditions appear in cervical smears in sheets or aggregates, or as miniature cells, either isolated or phagocytosed. In order to determine the tissue correlates of such cells, 116 cervical biopsies with a histopathologic diagnosis of papillomavirus (HPV) infection were reviewed and compared to previous findings in cytological smears; the patients were 18-65 yr of age. Eighty of the 116 cases had, in addition, cervical intraepithelial neoplasia (CIN). A much higher number of miniature dyskeratotic cells was recorded in the biopsies from patients with both HPV and CIN types of lesions (76.3% of the biopsies had isolated miniature cells and 41.3% showed phagocytosed miniature cells), compared to those with only HPV infection (19.4% with isolated and 5.5% with phagocytosed miniature cells). In addition, in the HPV plus CIN patients, the more advanced the neoplastic lesion, the higher the percentage of cases in which both types of dyskeratocytes are observed. These highly keratinized isolated miniature cells are found in, and are considered to arise from, the deeper layers of the epithelium; when phagocytosed they appear in the center of a concentric arrangement of cells. These cells constitute a pathological entity that can be distinguished from the sheets and aggregates of dyskeratotic cells that come from the superficial layers of parakeratotic epithelia.

Adolescent↗
PubMed1978

Further studies of periodic miniature response in squid giant axons.

Electric responses of extremely small amplitudes (1-30 muV peak-to-peak) repeating with more-or-less definite periodicity could be induced by a variety of chemical stimulants applied to squid giant axons either extracellularly or intracellularly. The chemical stimulants studied include allethrin, aminopyridines, N-bromosuccinimide, dimethylamino-pyridine, glutaraldehyde, osmium tetroxide, parachloromercuribenzoate, rose bengal, scorpion venoms and veratridine. With several mild stimulants, it was possible to evoke periodic miniature responses unaccompanied by a fall in the resting membrane potential. The frequency of miniature responses could be lowered by intracellular injection of TEA (tetraethylammonium). These miniature responses could readily be suppressed by external application of TTX (tetrodotoxin). The miniature responses evoked by 4-aminopyrine were characterized by a large variation in the frequency of responses. Cross-linking of the membrane proteins with a dilute solution of glutaraldehyde produced miniature responses repeating at progressively falling frequencies. Analyses of the processes of production of miniature responses with these and other stimulants have clarified several aspects of the physicochemical properties of the excitable sites of the axon membrane.

Animals↗
PubMed1976

Local anesthetic alteration of miniature endplate currents and endplate current fluctuations.

The effect of the local anesthetic QX222 on the kinetics of miniature endplate currents and acetylcholine induced endplate current fluctuations was studied in voltage clamped cutaneous pectoris muscle of Rana pipiens. Both the endplate current fluctuation spectra and the miniature endplate current decay consisted of two or three components depending upon the holding potential and local anesthetic concentration. The cutoff frequency of each spectral component was equal to the decay rate of its corresponding constituent of the miniature endplate current. Comparison of the relative amplitudes of the spectral and miniature endplate components indicated that QX222 did not act by creating two kinetically distinct populations of acetylcholine receptors. QX222 action could be explained by alteration of the acetylcholine receptors such that they sequentially change conformation form one open state to another. A specific case in which QX222 binds to the open state of the acetyl-choline receptor creating a blocked state, was found to account for the observed relationship between the relative amplitudes of the miniature endplate current and spectral components, as well as the previously observed voltage and concentration sensitivity of the decay rates of endplate current components.

Anesthetics, Local↗
PubMed1979

[Miniaturized methods to monitor intracranial pressure. Technical and clinical results (author's transl)].

The prognosis of numerous diseases of the central nervous system is essentially determined by the intracranial pressure (ICP) and its therapeutic influencing. Long-term monitoring of the ICP must therefore be the objective in neurological and neurosurgical patients at risk. For this purpose, miniaturized methods were tested and developed. To monitor the intracranial pressure in patients who were not operated on, a miniature pressure transducer the size of a match head was used which was directly implanted 'percutaneously' in the intensive care unit: After a stab wound had been made in the skin, a 5-mm burrhole is made; the specially constructed miniature coaxial burr which disengages as soon as it touches the dura automatically enables coplanar epidural implantation of the transducer by means of an adapter capsule. The skin is closed without tension. For monitoring the pressure after trepanation, a spiralled miniature pressure transducer is implanted. The equally flattened receiver with lateral membranes is placed intracranially as desired, e.g., epidurally or subdurally, durin the operation. The zero point can be checked from outside without danger of infection. After the end of the measurements the recorder is easily extracted. Up to the present time, the epidural pressure has been reliably monitored for several weeks by this method in 86 patients. Ten comparative measurements showed corresponding cerebrospinal fluid pressures to within a few mm Hg with very good reproduction of frequency and amplitude. Small zero drift and the external zero control give an accuracy of measurement +/- 5 mm Hg independently of the time of measurement. The measurement permits early recognition of progressive intracranial space-occupying lesions. In 14 patients (16%) a measured rise in intracranial pressure was an essential basis for indication for neurosurgical operations. In addition, the pressure measurement provides an objective assessment of the effect of measures to lower the ICP; progressive increases in intracranial pressure which cannot be influenced conservatively can be brought for surgical decompression in good time before the brain has been irreversibly damaged by pressure. In craniocerebral traumata, monitoring the intracranial pressure permits the differentiation of primary damage to the brain stem with uniform, normal intracranial pressure from secondary constrictions of the brain stem with considerable rise of intracranial pressure and disturbed autoregulation. Only in chronic subdural haematomata are considerable displacements of intracranial masses to be seen with only slightly increased ICP ( less than 30 mm Hg). Besides space-occupying lesions, the measurement of pressure also detects generalised epileptic attakcs due to a considerable rise in intracranial pressure caused by hyperemia. Also disorders of respiration are recognised by supervision of ICP. The procedures described seem suitable for routine monitoring of ICP in patients at risk, with little operative effort and minimum danger...

Adolescent↗
PubMed1992

Unitary, quantal and miniature GABA-activated synaptic chloride currents in cultured neurons from the rat superior colliculus.

The aim of this study was to identify the conductance change induced by one quantum of gamma-aminobutyric acid from axonal release sites on cultured superior colliculus neurons. Unitary (single cell-activated) inhibitory postsynaptic currents and spontaneous synaptic activity were recorded with patch clamp techniques in the whole cell configuration while superfusing the entire neuron with normal saline. Miniature inhibitory postsynaptic currents were recorded in the presence of tetrodotoxin and in reduced [Ca2+]o/[Mg2+]o. In addition, the membrane area contributing to synaptic activity was limited to a narrow window of 50 microns. Smaller neurons were chosen for recording to render a standard deviation of the "instrumental" noise of less than 1.5 pA at a holding voltage of -80 mV. After two weeks in vitro, the percentage of synaptically connected tectal neurons exceeded 50%. At holding voltages of -80 mV (Cl- equilibrium potential -12 mV) minimal amplitudes of unitary inhibitory postsynaptic currents were as low as 7-10 pA, while maximal amplitudes exceeded 500 pA. The mean time to peak and time constant of decay were 3.0 and 34.4 ms, respectively (n = 31). Fluctuating unitary inhibitory postsynaptic currents were deemed to be compound postsynaptic responses. Multiple Gaussian equations could be fitted to the amplitude histograms of unitary postsynaptic currents. This procedure rendered a quantal size between 5.0 and 10.9 pA (mean 7.1 pA; S.D. 1.78 pA) in five neurons from mature cultures. The amplitudes of statistically determined quantal inhibitory postsynaptic currents were slightly smaller than the independent estimate from somatic miniature inhibitory postsynaptic currents. The latter had a mean amplitude of 9.1 pA (S.D. 3.3 pA, n = 23), a mean time to peak of 1.65 ms (n = 9), and a mean time constant of decay of 16.2 ms (n = 9). Single channel recording from outside-out patches showed three to four main conductance states ranging from 9 to 22 pS. Single channel closures at the 21-24 pS level were occasionally observed during relaxation of miniature currents. The small size of whole cell quantal inhibitory postsynaptic currents and somatic miniature currents indicates that one GABA quantum opened only 5-15 single Cl- channels.

Animals↗
PubMed1992

Dual-component miniature excitatory synaptic currents in rat hippocampal CA3 pyramidal neurons.

1. Spontaneous miniature synaptic events were studied with tight-seal whole-cell recordings from CA3 neurons maintained in the hippocampal slice from immature rats (3-15 days). CA3 neurons suffer a constant, high-frequency barrage of inhibitory synaptic input. When inhibitory postsynaptic currents were suppressed by bicuculline, a smaller contribution from excitatory synapses was revealed. 2. Addition of tetrodotoxin (TTX) removed a persistent inward current and substantially reduced the baseline noise facilitating the detection of "miniature" excitatory currents. Addition of hyperosmotic media increased the frequency of spontaneous excitatory postsynaptic currents (EPSCs). 3. Under both physiological and elevated potassium conditions, individual spontaneous miniature EPSCs (10-30 pA amplitude) were composed of components mediated by N-methyl-D-aspartate (NMDA) and non-NMDA receptors as determined by their voltage dependence, time course, and sensitivity to selective antagonists. 6-Cyano-7-nitro-quinoxaline-2,3-dione (CNQX) or D-2-amino-5-phosphonovaleric acid (D-APV) shifted the amplitude distribution of miniature EPSCs to a smaller mode at both +40 mV and -40 mV. Similar to EPSCs recorded in CA1 neurons, the rise and decay times of the NMDA receptor component were slower than those of the non-NMDA component. The time course of the non-NMDA component was voltage independent. 4. In 13 of 21 neurons, no correlation existed between individual EPSC rise times and their corresponding halfwidth, peak amplitude, or decay time constant. This suggests that the large range of EPSC kinetics observed in each individual neuron was not due solely to cable attenuation of EPSCs widely distributed over the dendritic tree. Plots of the mean EPSC rise time against mean halfwidth for each cell, however, revealed a striking correlation, suggesting that in neonates, active synapses may be grouped in a restricted region of the dendritic tree and as such are subject to similar amounts of dendritic filtering. 5. The electrotonic length of CA3 neurons (L = 0.52) predicted that at this maturity the electrotonic compactness of the neuron facilitated voltage control over all but the most distal synapses. The reversal potential of the fast component of spontaneous events was close to 0 mV, whereas the reversal potential of exogenously applied kainate and NMDA was more positive. This discrepancy likely reflects a compromise of the voltage clamp by the activation of conductances distributed over the entire cell.(ABSTRACT TRUNCATED AT 400 WORDS)

2-Amino-5-phosphonovalerate↗
PubMed1992

Effect of free gingival grafts on naturally-occurring recession in miniature swine.

Miniature swine exhibit naturally-occurring, progressive recession on facial surfaces of the permanent mandibular incisors. The purpose of this study was to determine whether placing a free gingival graft to augment the width of keratinized gingiva of mandibular incisors in miniature swine would prevent or retard recession at the grafted site compared to an untreated contralateral control site. In 8 litter-mate miniature swine, free gingival grafts were placed on the facial surface of the permanent central and lateral incisors on one side of the mandible. The contralateral mandibular incisors did not receive any treatment and served as controls. Clinical measurements, including eruption, recession, pocket depth, attachment level, and keratinized gingival width were obtained preoperatively, 2 to 3 weeks after surgery to assess the success of gingival augmentation, and 3, 6, and 9 months postoperatively. Eight grafted sites were successful and showed significant augmentation of the keratinized gingival width, with a mean increase of 5.8 +/- 0.7 mm, while 6 grafts failed and showed a slight decrease in the mean width of -0.4 +/- 0.5 from the preoperative to postoperative examination. All sites showed significant recession during the experimental period. Successful sites showed no statistically significant or clinically major difference in the rate or amount of recession than contralateral control sites. By 9 months, the average increase in recession from the baseline examination was 2.8 +/- 1.5 mm for successfully grafted sites and 2.6 +/- 1.3 mm for contralateral controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

A practical miniature long-term bone marrow culture system for investigating early myelodysplasia.

A method was devised to grow haemopoietic cells in long-term bone marrow culture (LTBMC) which requires only 1 x 10(6) cells/culture. Such miniature cultures were used to study growth patterns of marrow from patients with myelodysplastic syndromes (MDS). Consistent differences in LTBMC cellularity and cellular composition were noted between MDS and normal marrow. These differences were accentuated by rGM-CSF. The criteria which distinguished between and MDS marrows were: cell count at weeks 1 and 4, % neutrophils and % blasts. In 10 patients with unexplained macrocytosis or pancytopenia miniature LTBMC results clearly segregated into either 'normal' or 'MDS' growth patterns. Miniature LTBMC with rGM-CSF may therefore be a useful diagnostic test for early MDS.

Adult↗
PubMed1992

Miniature postsynaptic currents recorded from identified rat spinal dorsal horn projection neurons in thin-slice preparations.

Whole-cell voltage-clamp recordings were made from spinothalamic and spinomesencephalic tract neurons in thin-slice preparations of rat spinal cord. In the presence of tetrodotoxin, spontaneous inward and outward postsynaptic currents were observed near the resting membrane potential. These currents were divided into miniature excitatory postsynaptic currents (mEPSCs) mediated by glutamate, and miniature inhibitory postsynaptic currents (mIPSCs) mediated by glycine or gamma-aminobutyric acid (GABA). Glutamatergic mEPSCs had two components mediated by NMDA and non-NMDA receptors. Analyzing these miniature synaptic currents, valuable information concerning the pre- and postsynaptic mechanisms underlying modulation of synaptic transmission in the spinal dorsal horn could be obtained.

Action Potentials↗
PubMed1992

Rapid-time-course miniature and evoked excitatory currents at cerebellar synapses in situ.

Neurotransmission from mossy fibre terminals onto cerebellar granule cells is almost certainly mediated by L-glutamate. By taking advantage of the small soma size, limited number of processes and short dendrite length of granule cells, we have obtained high-resolution recordings of spontaneous miniature excitatory postsynaptic currents (m.e.p.s.cs) and evoked currents in thin cerebellar slices. Miniature currents have a similar time-course and pharmacology to evoked currents and consist of an exceptionally fast non-NMDA (N-methyl-D-aspartate) component (measured rise-time, 200 microseconds; estimated pre-filtered rise-time less than 100 microseconds; decay time constant, tau = 1.0 ms), followed by 50 pS NMDA channel openings that are directly resolvable. We could find no evidence for the recent proposal that miniature currents in granule cells are mediated solely by NMDA channels with a novel time course. The non-NMDA receptor component of m.e.p.s.cs has a skewed amplitude distribution, which suggests potential complications for quantal analysis. The difference in time course between the m.e.p.s.cs reported here and other synaptic currents in the brain could reflect differences in synaptic function or electrotonic filtering; the relative contribution of these possibilities has yet to be established.

Animals↗
PubMed1979

The disposition of [14C]iprindole in man, dog, miniature swine, rhesus monkey and rat.

1. Absorption of a single oral dose of [14C]iprindole was rapid in rats, rhesus monkeys, miniature swine, dogs and human volunteers. In all species except the rat, most of the radioactivity in the blood resided in the plasma. Small amounts of unchanged iprindole were detected in the plasma of rats and rhesus monkeys but not in man and miniature swine. 2. Radioactivity was excreted mainly in the urine of man, miniature swine and rhesus monkey, but in the faeces of rat and dog. 3. Urinary radioactivity was associated with basic (free and conjugated), acidic and highly polar, water soluble metabolites. At least 20 metabolites as well as small amounts of unchanged drug were detected in the basic fractions of each species' urine. 4. Many of these metabolites were common to all species; however, qualitative as well as quantitative differences were apparent. Mass-spectrometric analysis of several metabolites indicated N-demethylation and oxidation of the alicylic ring or a combination of both pathways.

Animals↗
PubMed1975

Restraint, venipuncture, endotracheal intubation, and anesthesia of miniature swine.

Miniature swine are useful as experimental animals for investigations involving major surgical procedures, provided that proper restraint and anesthetic methods are employed. The methods and drugs described herein are not intended to be all-inclusive but rather those found most applicable to a wide variety of studies with miniature swine at this laboratory. This report is intended primarily to guide those unfamiliar in handling miniature swine during initiation of studies with that species. For chemical restraint during minor procedures, diazepam, at a dose of 5.5-8.5 mg/kg im, has become the drug of choice. For surgical anesthesia, optimal results have been obtained using thiamylal sodium iv for induction of anesthesia and maintained by 0.5-1.5% halothane administered via an endotracheal cannula. Pentobarbital sodium may be used to produce surgical anesthesia but is generally unsatisfactory except for terminal procedures. Electroanesthesia, even with concomitant use of tranquilizing drugs, is difficult to control and results in very poor muscle relaxation.

Anesthesia↗
PubMed1975

Hypotrichosis in Miniature Poodle siblings.

Progressive hypotrichosis was detected in 2 silver male Miniature Poodle siblings at 5 weeks of age. A male and 2 female siblings had normal black coats. The sire, a 3-year-old black Miniature Poodle, and the dam, a 2-year-old silver Miniature Poodle, also had normal coats. Microscopically, the hypotrichotic skin had accumulations of keratotic debris and melanin in dilated hair canals and melanin deposits in and around inactive hair bulbs. Sex-linked or sex-limited inheritance may have been involved, inasmuch as both affected dogs were males.

Alopecia↗
PubMed1978

Use of vectorcardiography for the detection of +Gz-related cardiac pathology in miniature swine.

Vectorcardiograms were recorded from anesthetized, adult miniature swine 1-2 weeks before high sustained +Gz exposure and 2-6 h after exposure. Each +Gz run consisted of one 60-s exposure, respectively, to 3, 5, 7, and 9 +Gz, with 3 min rest between each +Gz plateau. The full range, from severe to minor, of +Gz-induced cardiac pathology was observed in this group of miniature swine. In spite of the large variation in the amount and degree of cardiac pathology, there were no post-exposure vectorcardiographic changes which might be diagnostic of +Gz-induced cardiac pathology. The results of this study indicate that vectorcardiography, performed after +Gz exposure, is not a reliable technique for detecting the presence of +Gz-induced cardiac pathology in miniature swine.

Aerospace Medicine↗
PubMedDate not supplied

A miniature segment-length strain gauge arch for the assessment of myocardial function.

A miniature myocardial segment-length strain gauge arch utilizing solid-state strain gauge elements is described. The arch weighs 0.25 g, has a frequency response flat to 30 Hz, requires simple circuitry, and is stable in situ for periods exceeding 6 hours. Its miniaturization and ease of insertion offer distinct advantages over similar devices previously described. Miniature arches have been applied simultaneously to multiple sites to assess left ventricular function in dogs. The response of these arches to a variety of interventions indicates that this device may be used to follow localized segment-length and velocity changes. The study also clearly demonstrates that the orientation of strain gauge arches with respect to muscle fiber direction in the ventricular wall qualitatively and quantitatively affects the recorded segment-length alterations.

Animals↗
PubMed1992

Morphologic and clinical study of the retinal circulation in the miniature pig. B: Fluorescein angiography of the retina.

The retinal blood circulation was examined in 20 porcine eyes by studying fluoangiograms before and after occlusion of the temporal choroidal circulation. The use of a small intravenous bolus of 2.5 ml fluorescein provided high-resolution angiograms with detailed information of the retinal vascular bed. The lobular filling pattern of the choriocapillaris very closely resembles the human pattern. The intrinsic retinal vasculature of the miniature pig also has numerous characteristics in common with the human retina with regard to the extent of the vascular bed, the size of the blood vessels and the presence of radial peridiscal capillaries. Unlike the central fovea in the human eye, the porcine retina has a streak-like macular area which extends both temporally and nasally and which, although it is free of major blood vessels, is not completely avascular. This fluoangiographic study substantiates the results of the accompanying paper. It may be concluded that the miniature pig is a suitable experimental animal for applied research on the retinal vasculature.

Animals↗
PubMed1979

The free focus concept in dental and maxillofacial radiography. The present status of the miniaturized dental x-ray machines.

"Free focus" radiography has shown promise in the examination of complex anatomy in many parts of the body, where conventional and tomographic exposures provide limited information. The approach was introduced in dentistry three decades ago and applied clinically from the time the miniaturized x-ray machines with rod anodes became available in the early 1960's. Yet it has received little attention in the international literature. Recent generations of the unique machines allow free focus surveys of the dentition in two exposures with a film quality comparable to or better than conventional periapical surveys and with a fraction of the radiation load. There is a need for evaluation of such procedures for use in dental practice. Additional applications of free focus radiography promise unusual flexibility in the use x-ray examinations in endodontics, pedodontics, periodontics, and oral surgery, which may justify further development of the miniaturized equipment for such new approaches. Specific suggestions for technical improvements are discussed.

Dental Equipment↗
PubMed1992

Antibody avidity in swine lymphocyte antigen-defined miniature pigs.

Antibody avidity to hen egg white lysozyme (HEWL) was measured by thiocyanate ion elution enzyme-linked immunosorbent assay (ELISA) in swine lymphocyte antigen (SLA) defined miniature pigs. Serum antibody avidity was evaluated on day 14 and 30 after primary (day 0) and secondary (day 14) immunizations in eight to ten week old miniature pigs previously typed for swine lymphocyte antigen genotype. The effect of SLA genotype, litter, and gender on anti-HEWL antibody avidity was determined by least squares. Antibody avidity varied amongst individuals. Antibody avidity maturation was observed as a mean rise in antibody avidity from primary response (0.89 +/- 0.64) to secondary response (1.23 +/- 0.54) (p < 0.0005). Overall, SLA genotype did not significantly influence antibody avidity or avidity maturation, but pigs of dd genotype had greater avidity maturation between primary and secondary responses than other genotypes. Litter effects significantly affected antibody avidity and maturation.

Analysis of Variance↗