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PubMedDate not supplied

For insulin infusion: a miniature precision peristaltic pump and silicone rubber reservoir.

This paper describes a miniature precision peristaltic pump and a silicone rubber reservoir developed for the infusion of insulin in diabetic subjects. The ability of the 100-ml reservoir to maintain sterility of its contents over 26 refilling cycles (48 days) is demonstrated. Accelerated bench tests on 10 pumps over 30 days indicate an accuracy of +/- 1% on flow rate whether measured over 10 min or 24 h and with or without 1 atm of outlet back pressure. Comparison of calibrations made before and after 58 animal and clinical tests of 6--71 days' duration showed a percentage difference in calibration that varied with a mean +/- SD of 0.05 +/- 3.09%. Microscopic examination of pump tube samples after 21 days of clinical use indicated redistribution of surface material without evidence of particle spallation. Samples subjected to accelerated wear equivalent to 620 days of clinical use showed extensive luminal surface modification and particulate deposits on downstream filters. These were identified by X-ray spectroscopy as silicon compounds.

Animals↗
PubMedDate not supplied

Glucose sensor characteristics for miniaturized portable closed-loop insulin delivery: a step toward implantation.

An implantable glucose sensor must be free of baseline and sensitivity drift. To our knowledge, a drift-free glucose sensor with fast response time is not currently available. We are therefore proposing a miniature extracorporeal glucose sensor with access to the vascular system as a practical step toward implantation. This sensor could use existing technology to form the basis of a patient-wearable closed-loop system.

Blood Glucose↗
PubMedDate not supplied

A miniature glucose sensor, implantable in the blood stream.

We have developed a miniature glucose sensor using an oxygen electrode with a glucose oxidase membrane. The special character of this sensor is that the electrodes can be placed in a blood vessel and can measure the glucose level directly from the arterial blood stream if placed into an external A-V shunt. Its second notable characteristic is that the enzyme membrane is covered with a semipermeable membrane, which partially allows passage of glucose but only sufficient oxygen. This sensor is able to respond to glucose concentrations of up to 700 mg/dl in blood. This sensor loses 10% of its activity at about 200 h of continuous use, and 30% after 400 h of use. While the sensor cannot be sterilized by conventional mechanical or gas methods, certain antibiotics can be used for sterilization. To shorten the response delay of the sensor during the decreasing phase of glucose concentration, a thinner membrane is under development.

Blood Glucose↗
PubMedDate not supplied

Fabrication of miniature PO2 and pH sensors using microelectronic techniques.

Miniature PO2 and pH sensors can be used in combination with enzymatic catalysts such as glucose oxidase and glucose dehydrogenase as the basis for the development of a small glucose sensor. The applications of microelectronic techniques such as photolithography techniques and thick- and thin-film metallization are novel approaches in fabricating highly uniform and reproducible sensors that are relatively simple to calibrate and operate.

Blood Glucose↗
PubMed2001

Comparison of urine composition of healthy Labrador retrievers and miniature schnauzers.

OBJECTIVE: To compare urine composition in Labrador Retrievers (LR) and Miniature Schnauzers (MS) fed the same dog food. ANIMALS: 8 healthy LR (mean [+/- SD] age, 3.1+/-1.7 years) and 8 healthy MS (mean age, 3.7+/-1.3 years). PROCEDURE: A nutritionally complete dry dog food was fed to the dogs for 24 days. Urinary pH, volume, specific gravity, frequency of urination, and urinary concentrations of 12 analytes were measured for each dog; urinary relative supersaturation (RSS) with calcium oxalate and brushite (calcium hydrogen phosphate dihydrate) were calculated from these values. RESULTS: MS urinated significantly less often and had a lower urine volume (ml/kg of body weight per d) and a significantly higher urine pH, compared with LR. Urinary calcium concentration and brushite RSS were significantly higher in the urine of MS. As a result of a high calorie requirement, primarily as a result of high surface area to volume ratio, MS had significantly higher intake (per kg body weight) of dietary minerals, compared with LR. CONCLUSIONS AND CLINICAL RELEVANCE: Differences in urine composition exist between breeds fed the same diet, some of which, including lower urine volume, higher calcium concentration, and higher brushite RSS, may contribute to the high prevalence of calcium oxalate uroliths observed in MS. Differences between breeds should be considered when evaluating strategies for controlling calcium oxalate stone formation.

Animals↗
PubMed1982

A novel miniature bite force recorder and its clinical application.

Solid state components were used to construct a miniature bite force recorder suitable for registrations in large study groups. A semiconductor was chosen as the sensory unit. The complete recording system included a power supply, the bite force recorder, a chart recorder and a millivoltmeter. Laboratory calibration tests were performed to screen the limitations of the recorder. Series of loads were applied in the range from 10 to 1000 N. Eight females and eight males, 20 to 25 years old, were asked to produce a succession of maximum bites at three second intervals for as long as possible. The bite force recorder was positioned between the first molars on the left side. The laboratory tests showed that loads in the range from 10 to 1000 N were recorded with an error less than four percent. In the clinical tests, the mean maximal bite force was 500 N ranging from 330 to 680 N. The number of maximum bites varied from 5 to 27. No statistically significant differences were observed between the sexes as regards the maximal bite force and the number of bites.

Adult↗
PubMedDate not supplied

Evaluation of heating patterns of microwave interstitial applicators using miniature electric field and fluoroptic temperature probes.

The SAR patterns were determined for four commercially available microwave (915 MHz) interstitial applicators. Values of SAR were determined using a miniature (3 mm diameter) implantable isotropic electric field probe or a custom 0.25 mm diameter fluoroptic temperature probe. These are the smallest such probes that are currently available. Similar radial variation of SAR was found at the axial position of the gap in the outer conductor for each applicator. Electric field probe measurements are much faster and avoid some of the errors caused by the rapid spatial variation of SAR with interstitial applicators. The major limitation on the electric field probe is its size; it is larger than the applicators being tested.

Electronics, Medical↗
PubMed1993

The use of hydrophobic adhesive tape to produce miniature wells on microscope slides.

Hydrophobic adhesive tape was used to produce miniature wells on microscope slides for staining several sections of tissue with minimal amounts of cytochemical reagents. The wells could be tailored to individual specifications and the method allowed coverslips to be mounted close to the sections using either aqueous or xylene based mounting media. This method was especially useful for multiple immunolabelling of serial semithin cryosections.

Adhesiveness↗
PubMed1975

Miniature intravascular pCO2 sensors in neurosurgery.

In this study the authors compared PaCO2 measurements from a newly developed miniature intravascular pCO2 sensor for continuous on-line monitoring with those from a Radiometer bench instrument. In 10 patients undergoing craniotomy procedures, 84 paired comparisons were made. At the same time it was possible to follow continuously the trend of PaCO2 during deliberate hyperventilation, during the apneic period following hyperventilation, and during spontaneous respiration in the postoperative period. The comparisons showed an average difference in pCO2 of 1.62 +/- SE 0.15 torr. The apneic threshold for PaCO2 after passive hyperventilation was lower than in the awake patient. After the period of apnea no hypoxemia occurred. In the recovery room the PaCO2 increased and the PaO2 decreased. The latter decreased to subnormal levels in two patients more than an hour postoperatively.

Apnea↗
PubMed2003

A new, miniature ultrasonic surgical aspirator with a handpiece designed for transsphenoidal surgery. Technical note.

The authors describe an innovative surgical instrument designed to remove hard fibrous masses from the pituitary region, which cannot be completely removed using standard transsphenoidal surgical procedures. The innovative features of the instrument include a miniature ultrasonic surgical aspirator and an extra-long bayonet handpiece with a 1.9-mm-diameter translucent tip. Intraoperative use of this refined device may increase the effectiveness of the removal of fibrous lesions within a narrow operative field, while also preserving surgical safety.

Craniopharyngioma↗
PubMed1975

Effect of chronic ethanol ingestion on mitochondrial protein synthesis in Sinclair(S-1) miniature swine.

The effect of chronic ethanol ingestion on hepatic mitochondrial protein synthesis in miniature swine was investigated. After 3 wk on test, there was no decrease in the rate of amino acid incorporation between livers of control and ethanol consuming pigs. After 6 wk on test, there was a 33% decrease in rate of hepatic mitochondrial membrane protein synthesis in livers of experimental pigs, as compared with controls. When analyzed by SDS-gel electrophoresis, a decrease in labeling of the 40,000 mol wt peak, from both whole membrane protein and proteolipid protein profiles, was observed for livers from ethanol consuming pigs as compared with controls.

Animals↗
PubMed1989

Mucus transport in a miniaturized simulated cough machine: effect of constriction and serous layer simulant.

The transport of mucus gel simulant (MGS) in a constricted simulated cough machine, using blood plasma as a serous layer simulant (SLS), was investigated. MGS was prepared from locust bean gum solutions crosslinked with varying amounts of added borate to produce gels of varying spinnability (filance). The model trachea was a plexiglass channel of rectangular cross-section with the plane bottom surface. The upper surface included a sinusoidal protrusion which provided a flow convergence with minimum gaps of 6, 4 and 2 mm. Experiments for mucus transport were conducted for these minimum gaps, as well as for the non-convergent case (12 mm gap). Miniaturization of sample quantity was achieved by keeping the MGS layer depth constant (0.5 or 1 mm) but reducing the zone of loading from 13.4 cm to 1 cm, thus reducing the sample requirement to as little as 0.2 ml. MGS transport was determined as the minimum displacement of a line of marker dye placed in the MGS layer at the point of minimum constriction gap. It was shown that in all cases (dry as well as with SLS), MGS transport increased as the minimum constriction gap between the plane and the convergent top surface decreased. This increase was further enhanced if an SLS of lesser viscosity was used. It was also found that the transport of MGS increased as the depth of MGS layer increased or as the filance decreased in both non-constricted and constricted cases. The relationship between MGS transport and filance was maintained even in the presence of an SLS layer.

Airway Obstruction↗
PubMed2006

Different sensitivity of miniature endplate currents of the rat extensor digitorum longus, soleus and diaphragm muscles to a novel acetylcholinesterase inhibitor C-547.

A novel derivative of 6-methyluracil, C-547, increased the amplitude and prolonged the duration of miniature endplate currents (MEPCs) which is typical for acetylcholinesterase inhibition. In the soleus and extensor digitorum longus significant potentiation was detected at nanomolar concentrations. In contrast, in the diaphragm muscle, the increase in the amplitudes of the MEPCs and the decay time constant appeared only when the concentration of C-547 was elevated to 1 x 10(-7) M. Possible consequences for the exploitation of this drug, which can selectively inhibit AChE in particular synapses, are discussed.

Animals↗
PubMedDate not supplied

Disseminated Mycobacterium avium--intracellulare complex infection in a miniature schnauzer.

A two-year-old, spayed female, miniature schnauzer was evaluated for respiratory distress associated with a compressive cervical mass. Generalized mycobacterial infection was diagnosed from aspirates of several enlarged lymph nodes. Tissue specimens further identified Mycobacterium avium--intracellulare using polymerase chain reaction followed by nucleic acid hybridization. Treatment with enrofloxacin, clofazamine, rifampin, and interferon did not result in long-term success.

Animals↗
PubMedDate not supplied

Bone plate fixation of distal radius and ulna fractures in small- and miniature-breed dogs.

Bone plate fixation was reviewed in 29 distal radial fractures of small- and miniature-breed dogs. Twenty-two fractures in 18 dogs were available for follow-up. Number of complications and return to function were evaluated. Complications occurred in 54% of the fractures. Catastrophic complications occurred in 18% of fracture repairs with follow-up, while minor complications occurred in 36%. Sixteen (89%) of 18 dogs had a successful return to function. Bone plate fixation is a successful repair method for distal radius and ulna fractures in small-breed dogs, compared to previously reported methods.

Animals↗
PubMed2006

Identification and characterisation of five novel miniature inverted-repeat transposable elements (MITEs) in amphioxus (Branchiostoma floridae).

As the sister group to vertebrates, amphioxus is consistently used as a model of genome evolution for understanding the invertebrate/vertebrate transition. The amphioxus genome has not undergone massive duplications like those in the vertebrates or disruptive rearrangements like in the genome of Ciona, a urochordate, making it an ideal evolutionary model. Transposable elements have been linked to many genomic evolutionary changes including increased genome size, modified gene expression, massive gene rearrangements, and possibly intron evolution. Despite their importance in genome evolution, few previous examples of transposable elements have been identified in amphioxus. We report five novel Miniature Inverted-repeat Transposable Elements (MITEs) identified by an analysis of amphioxus DNA sequence, which we have named LanceleTn-1, LanceleTn-2, LanceleTn-3a, LanceleTn-3b and LanceleTn-4. Several of the LanceleTn elements were identified in the amphioxus ParaHox cluster, and we suggest these have had important implications for the evolution of this highly conserved gene cluster. The estimated high copy numbers of these elements implies that MITEs are probably the most abundant type of mobile element in amphioxus, and are thus likely to have been of fundamental importance in shaping the evolution of the amphioxus genome.

Animals↗
PubMed1976

Miniature chromatography of haemoglobin A2 and heterozygous beta thalassemia.

172 beta thalassemias are detected by applying a new method of haemoglobin A2 determination: Miniature chromotography on DEAE cellulose. This procedure is simple, fast, accurate and there is no significant difference with macro-chromatography. It is proposed as standard method for determination of hemolgobin A2. This study was made on 400 patients suspected of beta thalassemia, the majority of which presented with a considerable microcythemia.

Adolescent↗