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At least 1,765 records · Page 98Linked to original sources
PubMed1979

Serum electrolyte concentrations in Sinclair(S-1) miniature swine from 1 through 36 months of age.

Venous blood samples were collected monthly from 60 male and 60 female Sinclair(S-1) miniature swine from 1 through 36 months of age. The rate of serum urea nitrogen concentration decreased instantaneously for females and increased instantaneously for males as described in the equation y = aebt. Serum creatinine concentration decreased through 20 months of age and increased from 20 through 36 months of age. Serum calcium, inorganic phosphorus, potassium and sodium concentrations decreased instantaneously through 36 months of age. From 14 through 36 months of age, males had a greater mean serum urea nitrogen concentration than did females.

Age Factors↗
PubMed1968

Screening for bacteriuria by the miniature culture technique.

Two hundred and eighteen urine specimens were cultured in duplicate to compare the reliability of a miniature culture technique with a more standard, calibrated loop-method for quantitative urinary bacteriology. The new method appears to be reliable: the rate of false negative results was 2.5 percent and of false positive 3.6 percent. The correlation with the standard method was best in the ranges of 0 to 10,000 and greater than 100,000 colonies per milliliter. The technique is simple, quick, and easily applicable to the physician's office laboratory.

Bacteriological Techniques↗
PubMed1979

Regional cerebral blood flow in conscious miniature swine during high sustained +Gz acceleration stress.

The two major factors limiting performance during high +Gz acceleration stress are loss of vision, and loss of consciousness. These symptoms are believed to occur as a result of insufficient blood flow to the retina and brain. This study was conducted to determine the effects of +Gz stress on regional cerebral blood flow. Cerebral blood flow (CBF) was measured in 22 conscious, female, miniature swine with the radio-labeled microsphere technique. Acceleration exposures consisted of 60-S plateaus at +3Gz, +5Gz or +7Gz. Microsphere infusions were made before, during, 1.0-6.0 min after, and 10 min after +Gz. Blood flow to the retina was significantly decreased during exposure to +5Gz and ceased during exposure to +7Gz stress. Mean, resting control CBF was 34 +/- 4 ml/min/100 g. Exposure to +3Gz and +5Gz had no significant effect on CBF. Exposure to +7Gz appeared to cause a redistribution of CBF, with blood flow to the brain stem being preserved and flow to the cerebrum being diminished.

Acceleration↗
PubMed1977

[Test of combination of the agents coumarin and troxerutin for embryotoxic and teratogenic side-effects in Göttingen miniature pigs (author's transl)].

Göttingen miniature pigs were used to test a combination of the active principles coumarin and troxerutin (Venalot) for teratogenic and embryotoxiic side-effects. The experimental group consisted of 17 mother pigs with 95 fetuses, the control group of 6 untreated sows with 45 fetuses. The combination of coumarin and troxerutin was administered orally at a level of the 100-fold therapeutic dose (i.e. 25 mg coumarin + 150 mg troxertutin/kg/day) from day 6 to day 30 of gestation. The pathological and histological examinations of the uteri and fetuses revealed no indications of any embryotoxic or teratogenic damage caused by the tested combinations. Morphological and clinico-chemical investigations did also not result in any findings definitely attributable to the medication.

Animals↗
PubMed1980

[Statistical analysis of the structure of a train of miniature endplate potentials following different treatments of the process of transmitter secretion].

The process of transmitter release has been statistically analysed with the use of a rat phrenic nerve-diaphragm preparation in which spontaneous transmitter secretion had been changed by ouabain, 4-aminopyridine and tetanus toxin. In all cases significant deviations of the statistics of miniature end-plate potentials (MEPP) impulse flows from Poisson process and amplitude distributions of MEPP from normal have been obtained. By the statistical characteristics two groups of processes have been distinguished: 1) normal and ouabain where certain consistency of the processes suggests the organization of transmitter release sites and 2) 4-aminopyridine and tetanus toxin where the temporary characteristics of the process in conjunction with the appropriate transformation of MEPP amplitude distribution apparently suggests breakdown of the mechanism of spontaneous synchronization of transmitter quanta release.

Aminopyridines↗
PubMed1983

[Multimodality in the amplitude distribution of miniature endplate potentials due to the action of spatially discrete areas of transmitter release].

Miniature end plate potentials (MEPPs) were simultaneously recorded in frog sartorius muscle by two intracellular microelectrodes. Some isolated groups of points (clouds) were found on the diagram of MEPPs scatter. Several peaks each of which was composed of signals from certain clouds (or from several clouds) on the scatter diagram were found on the histograms of MEPPs amplitude distribution. It is assumed that the clouds on the scatter histogram and the peaks on the histogram of MEPPs amplitudes are formed at the cost of secretion of quantum acetylcholine from spatial separate areas of transmitter release. The data obtained do not correspond with the subquantum hypothesis of transmitter release in neuromuscular junctions.

Animals↗
PubMed1980

Alterations in cardiac rate and rhythm in miniature swine during simulated aerial combat maneuver +Gz stress.

Electrocardiograms (McFee-axial reference system) were recorded from 18 chronically instrumented, conscious, female miniature swine before, during, and after exposures to +Gz stress. The animals were exposed to five simulated aerial combat maneuver (SACM) type acceleration profiles which spanned approximately 106 s and included two 5-s +9Gz peaks. A 5-min rest period separated each SACM exposure. Maximum heart rates during +Gz decreased over the course of the 5 SACM's-241 +/- 4 b/m and 224 +/- 5 b/m for the first and last exposures, respectively. Resting heart rates obtained 5 min after each SACM exposure were steadily increased from a control of 86 +/- 5 b/m to a final of 129 +/- 8b/m. Of the 18 animals studied, 10 developed arrhythmias during +Gz, or within the first minute after +Gz exposure. Arrhythmias exhibited included premature atrial and ventricular contractions, intraventricular conduction defects, sinus arrhythmias, premature junctional contractions, atrial bigeminy, ectopic atrial and ventricular rhythms, complete A-V dissociation, left anterior arborization-block, and junctional rhythms with aberrant conduction. While arrhythmias were not uncommonly observed during +Gz, most occurred at the end of the SACM profile or immediately following the SACM.

Animals↗
PubMed1982

Transplantation in miniature swine. XII. N-terminal sequences of class I histocompatibility antigens (SLA) and beta 2-microglobulin.

Purified class I histocompatibility antigens (SLA) from three haplotypes were prepared by papain treatment of lymphoid cell membranes obtained from spleens and lymph nodes of miniature swine homozygous at their major histocompatibility complex. Antigens were purified by ion-exchange chromatography followed by gel filtration. Purity was analyzed by SDS-PAGE, and antigenic specificity by inhibition of complement-dependent, alloantiserum-mediated cytotoxicity. The SLA antigens were reduced and alkylated, and the component heavy and light chains were isolated by gel filtration under dissociating conditions. N-terminal amino acid sequences were obtained for SLAaa, SLAcc, and SLAdd heavy chains, as well as for the light chain, beta 2-microglobulin. The swine antigens showed high levels of homology with class I antigens from other animal species. Heterogeneity was observed among the swine haplotypes, and several of the positions at which substitutions were found are apparently invariant in other animal species. In contrast, only minimal sequence heterogeneity was detected within haplotypes, the basis of which may be of relevance to understanding the evolutionary development of these molecules.

Amino Acid Sequence↗
PubMed1982

Pathogenesis of progressive rod-cone degeneration in miniature poodles.

Visual cell pathologic changes and outer segment renewal were investigated in miniature poodles with progressive rod-cone degeneration. Early in this disease, visual cells in the posterior pole and equatorial regions show outer segment lamellar disorientation and vesicular profiles. Visual cells are normal in the periphery. Outer segment renewal determined after intravitreal injection of 3H-leucine was abnormally slower in affected animals than in controls. This renewal abnormality was similar in structurally normal and diseased photoreceptors, suggesting that the renewal defect is the earliest recognizable abnormality in the disease. The pigment epithelium was normal; the presence and density of pigment did not appear to affect the extent and severity of the disease or modify the abnormal renewal rate. As the disease progressed, photoreceptor outer segments were lost, and the remaining diminutive photoreceptors accumulated label in the inner segment and perinuclear zones. Sodium dodecyl sulfate gel electrophoresis of crude rod outer segment preparations showed no differences in opsin synthesis between normal and affected retinas early in the disease, but opsin synthesis decreased in the late stage of the disease.

Animals↗
PubMed1982

[Effect of carbacholine on miniature potentials and currents of rat skeletal muscle endplates].

In rat soleus muscle placed in solution with 13 mumol/l potassium chloride carbachol (10 mumol/l) caused a marked increase in miniature end-plate potentials frequency. Intensification of spontaneous mediator release was also observed under clamping of the membrane potential of the muscle fibre at potassium equilibrium potential level. It is concluded that carbachol presynaptic effect on spontaneous acetylcholine release is not connected with postsynaptic membrane depolarization and results from direct mimetic action on the motor nerve terminals.

Acetylcholine↗
PubMed1978

[Obtaining and rearing germ-free miniature piglets for biomedical research].

The method of obtaining and rearing germfree miniature piglets for medical-biological research is described. The gnotobiotes were reared in rigid organic glass isolation cells up to 3 months. Milk diets supplemented with minerals and vitamins were used for nutrition. The gnotobiotes gained weight well during the whole observation period.

Animal Husbandry↗
PubMed1983

Complex total hip replacement for dysplastic or hypoplastic hips using miniature or microminiature components.

We analyzed the preoperative and perioperative data on sixty-nine consecutive complex total hip replacements performed in fifty-seven patients using miniature or microminiature custom-made femoral components. The patients' average age was 45.7 years. The preoperative diagnosis was congenital dysplasia or dislocation of the hip in 72 per cent of the hips. Acetabular bone grafts were required in thirty-seven of the sixty-nine hips. Operative complications occurred in thirteen (19 per cent) and postoperative dislocation occurred in eleven (16 per cent) of the sixty-nine hips. Fifty-five hips in forty-seven patients were followed for a minimum of two years, the average follow-up being 4.8 years and the longest, 9.8 years. All acetabular grafts united. Loosening of one or both prosthetic components occurred in ten (18 per cent) of the fifty-five hips (twelve of the 110 components became loose). There were no instances of a stem bending or fracturing, despite the small size of the femoral components. Eight hips (14.5 per cent) had undergone revision, six for painful loose components and two for recurrent dislocation. For the forty-seven hips that were not revised, the average Harris hip score rose from 43 points preoperatively to 80 points postoperatively.

Adolescent↗
PubMed1981

Natural killing (NK) and antibody-dependent cellular cytotoxicity (ADCC) in specific pathogen-free (SPF) miniature swine and germfree piglets. III. Two distinct effector cells for NK and ADCC.

Effect of "anti-NK" sera on NK and ADCC activities was examined to study further the relationship between the effector cells for NK and ADCC in specific pathogen-free miniature swine. An appropriate dilution of "anti-NK" sera that had no effect on ADCC activity not only inhibited NK activity but also eliminated NK cells in the presence of C which supports the presence of NK cells distinct from K cells for ADCC.

Animals↗
PubMed1984

[Failures with screwed miniaturized plates. Apropos of 4 cases].

It is exceptional for surgery to become necessary after the use of miniaturized plate and screws. When it is required it is because of faulty reduction or contention, mucosal disunion or an infective focus, or a combination of these factors. Surgery provides good final results, but 2 to 4 supplementary months of immobility are needed, and it can be avoided by respecting the indications and practical necessities of this method.

Adult↗
PubMed1983

[Experimental studies on the genesis of low-frequency vibrations (M-sound) of the first heart sound using a miniature accelerometer].

We studied eight mongrel dogs, weighing 15 to 35 kg, in which an initial low-frequency vibration of the first heart sound (M-sound) was recognized on the chest wall. A miniature accelerometer weighing 0.5 gm was used to record surface velocity signals and surface acceleration signals as well as phonocardiograms over the cardiac apex of the closed chest wall and over the pericardium or epicardium. The frequency response of accelerometer was essentially flat (+/- 1.5 dB) from 1 to 200 Hz. The accelerometer mounted was such that its sensitive axis was perpendicular to the recording surface. Equisensitive phonocardiograms were obtained to compare the signal size of M-sound on the epicardium at several positions including the cardiac apex, the left ventricular anterior wall near the interventricular septum, the left ventricular antero-lateral wall and the right ventricular anterior wall. Intraventricular phonocardiograms and pressure curves were obtained by a Millar catheter directly inserted through the left ventricular wall near the apex to keep the tip near the apex. Furthermore, the relationship between M-sound and the shortening of the myocardium at the apex was investigated by means of ultrasonic dimension system and phonocardiography. Studies of M-sound were performed not only in sinus rhythm, but also in atrio-ventricular dissociation and ventricular pacing after crushing sinus node or electrical vagus stimulation. The results were as follows: The M-sounds over the chest wall, pericardium and epicardium were recorded coincidentally with the onsets of the left ventricular pressure curve, its dP/dt, low-frequency vibration of the first heart sound of intraventricular phonocardiogram, positive velocity, and acceleration of myocardial surface. The M-sound on the epicardium was maximal in intensity at or near the cardiac apex, in comparison with those recorded on the left ventricular anterior wall near the interventricular septum, left ventricular antero-lateral wall, and right ventricular anterior wall. The M-sound was observed between A and C points of the mitral valve echogram. There was no effect of atrial contraction on the M-sound in cases of atrio-ventricular dissociation. The onset of the M-sound on the epicardium at the apex was not always coincident with the onset of shortening of the myocardium at the same position.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

A miniaturized agar culture system for cloning human erythropoietic progenitor cells.

The micro-agar-culture technique for cloning early and late erythropoietic progenitor cells (BFU-E and CFU-E) was further modified and miniaturized in order to study the optimal growth conditions with a minimal consumption of erythropoietin (EP). Using microtiter plates, the total incubation volume was lowered from 0.5 to 0.1 ml and thus reduced the necessary amount of EP and cells by a factor of 5. The method consists of a 50 microliter agar layer, in which the mononuclear cells are suspended, and a 50 microliter liquid overlayer containing bovine serum albumin (BSA), transferrin (TF), and EP. After a seven- or 14-day incubation, the whole agar layers were fixed, transferred to microscopic slides, dried, stained using the Pappenheim method, and permanently preserved. The influences of FCS, BSA, and TF in the presence of EP were studied on the proliferation of human bone marrow CFU-E and BFU-E. The variation of FCS concentration showed an optimum at 10%. The addition of BSA in the presence of optimal concentrations of EP markedly increased the number of BFU-E, but not CFU-E. Furthermore, the threshold concentration of EP required for the initial burst formation could be reduced by half in the presence of BSA. By the addition of TF, a further increase in the number of BFU-E was obtained.

Agar↗
PubMed1981

Tyrosinase activity and isoenzyme distribution corresponding to growth and regression of melanoma in Sinclair miniature swine.

Malignant melanomas have been shown to contain high levels of monophenol monooxygenase (tyrosinase) enzyme activity; the enzyme is responsible for melanin synthesis. The melanoma of Sinclair miniature swine has a high incidence of spontaneous regression and thus provides a unique system for analyzing changes in tyrosinase activity at various tumor stages. Three tumor stages (progressively growing tumors, partially regressed tumors, and fully regressed tumors) were analyzed for tyrosinase activity. The progressing tumors were 34-fold higher than were the partially regressed lesions and 400-fold higher than were the fully regressed tumors. Histologically, the decrease in enzyme activity correlated with a loss of tumor cells. Sequential biopsies of tumors during the course of tumor development showed a positive correspondence between tumor volume and tyrosinase activity for the early and late stages of tumor growth and regression. Electrophoretic separation of tyrosinase preparations revealed three major tyrosinase "isoenzymes" whose relative abundance fluctuated during developmental increases and decreases in enzyme activity.

Age Factors↗
PubMed1981

Transplantation in miniature swine. X. Evidence for non-SLA-linked immune response gene(s) controlling rejection of SLA-matched kidney allografts.

The survival of renal allografts between SLA-matched swine has been found to be subject to non-SLA-linked Ir gene control. Using three herds of miniature swine, each homozygous for a different SLA haplotype (designated aa, cc, and dd, respectively), we initially observed that all animals of the c haplotype rejected SLA-matched renal allografts. In contrast, the subset of dd animals which were the product of continuous homozygous matings since establishment of the dd herd (ddR) accepted SLA-matched grafts indefinitely without any immunosuppression. A formal backcross study was therefore performed in which offspring of (cd x ddR) matings (designated cdbc and ddbc) were bilaterally nephrectomized and transplanted with SLA-matched renal allografts. Acceptors and rejectors were found among both backcross types, with a total of 6 of 17 (35%) of the animals dying of renal failure secondary to rejection. When ddbc animals were used as donors for ddR recipients, all grafts were accepted, ruling out the possibility that rejection was attributable to strong non-SLA antigens segregating within the cc herd. These results are consistent with a model in which rejection of SLA-matched renal allografts is controlled by either one or two non-SLA-linked immune response genes. These findings raise the possibility that the observed 5 to 15% frequency of rejection of HLA-identical living related donor renal allografts in man could involve similar immune response gene control.

Animals↗