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Insulin injection technique has far greater bearing on glycaemic control than is often recognised. This article discusses the optimal needle length for different injection sites and highlights other crucial aspects, such as needle re-use, importance of adequate mixing of cloudy insulin, and the way pen devices should be stored.
BACKGROUND AND OBJECTIVES: Successful regional anesthesia involves a three-dimensional visualization of anatomy and an informed approach to needle placement and repositioning. This study trigonometrically examines the relationship between needle insertion angle and resultant needle position. METHODS: Needle position during advancement of 2-inch (5.1-cm), 3 1/2-inch (8.9-cm), and 5-inch (12.7-cm) needles was trigonometrically determined. Starting at 90 degrees, the angle of needle insertion theta (measured from the perpendicular) was decreased in 5 degrees and 10 degrees increments, and the resultant change in needle position was calculated by using a computer model. Needle depths relevant to the three needle lengths were studied and ranged from 0.5 to 11.0 cm. The effects of needle insertion angle, redirection angle, and depth on resultant needle position were evaluated. RESULTS: The mean change in needle position was significantly less with a 5 degree redirection of the needle than with a 10 degree needle redirection. In addition, the mean change in needle position was highly correlated with increasing needle depth and acute angle of needle insertion. CONCLUSIONS: Incremental needle redirection of 5 degrees allows a precise survey of neural and adjacent anatomy and results in approximately one half the change in needle position occurring with a 10 degree angle of redirection. However, a 10 degree angle of redirection may result in walking over the desired neural structure.
UNLABELLED: An in vitro examination of 25-gauge Quincke and 25-gauge and 27-gauge Whitacre spinal needles was performed after insertion in 210 consenting adult patients. In addition, 300 unused Quincke needles and 300 unused pencil-point needles were examined under a dissecting microscope. When the microscopic evaluation was performed on the needles after spinal blockade, burrs or blunting of the needle tip were noted in 24% of the Quincke needles compared with only 3% of the 25-gauge Whitacre needles and 10% of the 27-gauge Whitacre (P < 0.05). Bony contact with 25-gauge Quincke and 27-gauge Whitacre needles resulted in an increased incidence of microscopic tip damage (versus 25-gauge Whitacre). Needle-tip damage with the Whitacre needles was limited to blunting of the tip. The analysis of unused needles revealed significant differences among manufacturers of the cut-bevel needles with respect to stylet-to-needle length and burrs on the end of the stylet. The leading edge of the stylet protruded beyond the opening of the needle tip in 7% of the Quincke needles. However, only minor needle-tip abnormalities were noted with the pencil-point needles (i.e., variability in the side-port opening to needle tip distance, side-port opening integrity). In conclusion, bony contact produced more damage to the cut-bevel than to the pencil-point needle tips. In addition, fewer inherent manufacturing defects were noted with the pencil-point versus cut-bevel needles. IMPLICATIONS: It has been suggested that damaged needle tips may contribute to a higher incidence of headaches after spinal anesthesia. A microscopic examination revealed that the pencil-point (versus cut-bevel) needles had fewer manufacturing flaws and were less susceptible to tip damage when bony contact occurred during the placement of the spinal needle.
The mechanisms behind length regulation of prokaryotic surface structures has long eluded microbiologists. The recent identification of a protein that functions as a 'molecular ruler' to determine the physical length of a bacterial extracellular needle advances our understanding of surface structure biogenesis.
UNLABELLED: The purpose of this study was to evaluate four pencil-point spinal needles commonly used for combined spinal-epidural (CSE) anesthesia. Four hundred-seven consecutive parturients undergoing cesarean delivery or labor analgesia received a CSE block with a randomly selected pencil-point spinal needle (Becton-Dickinson [B-D] 27-gauge, 119-mm Whitacre; B-D 27-gauge, 120-mm Durasafe; B-D 25-gauge, 120-mm Durasafe; or International Medical Devices' 26-gauge, 124-mm Gertie Marx). Success in obtaining cerebrospinal fluid (CSF) and the incidence of transient paresthesias and postdural puncture headache (PDPH) were compared by using chi2 testing; P < 0.05 was considered significant. Failure to obtain CSF (3%-5%) was not significantly different among spinal needles. The Gertie Marx 26-gauge needle was associated with significantly more paresthesias (29%) than the Whitacre 27-gauge needle (17%). The combined incidence of paresthesias with the Durasafe 25-gauge and Gertie Marx 26-gauge spinal needles (28%) was greater than the combined incidence of paresthesias with the Durasafe 27-gauge and Whitacre 27-gauge needles (18%). The incidence of PDPH did not differ among the four pencil-point spinal needles. We conclude that longer spinal needles are associated with a significantly more frequent incidence of transient paresthesias without residual effects. IMPLICATIONS: The use of four pencil-point spinal needles in the combined spinal-epidural technique is associated with an inconsequential incidence of spinal headache, a low incidence of paresthesias that are transient with no long-term effects, and a high degree of success independent of spinal needle length.
Type III secretion machinery (TTSM), composed of a needle, a basal body, and a C-ring compartment, delivers a subset of effectors into host cells. Here, we show that Shigella Spa33 is an essential component of the C-ring compartment involved in mediating the transit of various TTSM-associated translocated proteins. Electron microscopic analysis and pull-down assay revealed Spa33 to be localized beneath the TTSM via interaction with MxiG and MxiJ (basal body components). Spa33 is also capable of interacting with Spa47 (TTSM ATPase), MxiK, MxiN (required for the transit of MxiH, the needle component), Spa32 (required for determining needle length), and several effectors. Genetic and functional analyses of the Spa33 C-terminal region, which is highly conserved in the SpaO-YscQ-HrcQ(B)-FliN family, indicate that some of the conserved residues are crucial for needle formation via interactions with MxiN. Thus, Spa33 plays a central role as the C-ring component in recruiting/exporting TTSM-associated proteins.
Table bombardment by automated biopsy needle is an occasional technical problem during stereotactic core biopsy of the breast. It is most commonly encountered in small breasts and when lesions are close to the biopsy table. A reference chart is devised for stereotactic core biopsy using an add-on erect stereotactic biopsy table and automated spring-loaded biopsy gun. The chart serves as a reference for pre-biopsy assessment of the feasibility of core biopsy in the vertical approach due to the constraints of lesion depth and breast thickness. It allows easy and quick reference for the required needle length input for the stereotactic system to prevent table bombardment.
INTRODUCTION: Because transmission of HIV to health care workers after needlestick injury has occurred mainly a result of deep insertion of large gauge needles, blood and viable mononuclear cells transferred after needlestick injury were measured. METHODS: Needles of 20 to 27 gauge were filled with HIV-1 seropositive blood and inserted through extracorporeal human skin or parafilm covering physiologic saline solution modified Drabkin's solution, or culture medium, or inserted directly into one of these fluids, to a depth of one third of the needle length (0.5 inch) for 1 second. Volume of blood transferred was measured by both modified Drabkin's method and by chromium 51 labeling of red blood cells. Transfer of viable mononuclear cells was measured by growth in culture medium containing autologous feeder cells. RESULTS: The volume of blood transferred from a needle passed through skin varied from 312 +/- 69 nl from a 20-gauge needle to 14 +/- 4 nl from a 27-gauge needle, as measured by modified Drabkin's technique, and from 404 +/- 80 nl to 12 +/- 3.1 nl, as measured by chromium 51 labeling of red blood cells. The volume of blood transferred from a needle passed through parafilm was twice that transferred through skin. The volume of blood transferred through skin was 40% that transferred directly into fluid not covered by any barrier; blood transferred through parafilm was 80% of that transferred directly. When needles containing blood were inserted into culture medium for 1 second in the absence of a barrier, at least one viable mononuclear cell was almost always transferred to fluid from all gauges of needle tested. Insertion of needles through skin prevented transfer of all viable mononuclear cells from only 3% to 5% of 20- to 23-gauge needles, and from 12% to 32% of 26- and 27-gauge needles. Parafilm was an even less effective barrier than skin. Insertion of needles through parafilm completely prevented transfer of viable mononuclear cells from no 20- to 23-gauge needles and from only 5% to 10% of 26- and 27-gauge needles. CONCLUSION: The volume of blood transferred after needle insertion through skin for 1 second varied with the gauge of the needle and was 30-fold higher from a 20-gauge than from a 27-gauge needle. Variable mononuclear cells were transmitted after insertion through skin from more than 95% of 20- to 23-gauge needles and from 68% to 88% of 26- and 27-gauge needles. Parafilm was less effective than skin in reducing transmission of blood and viable mononuclear cells.
PURPOSE: To estimate the accuracy of the determination of tip position of MR compatible biopsy needles based on signal voids and artifacts in MR guided biopsies. METHOD: In a nylon grid phantom an MR compatible 18G needle (E-Z-EM) was measured in a 1.0 T imager using TSE- and FFE-sequences of 20 s and 40 s duration in 34 different orientations of needle versus B0, frequency and slice selection gradient. 4 radiologists with no experience in the evaluation of signal void artifacts estimated the needle tip positions from needle tip artifacts. The readers determined the needle tip before and after a 15 minute training session based on high resolution images with explanation of size and shape of specific artifacts of biopsy needles in 12 different orthogonal or parallel orientations to B0 and frequency encoding gradient that are possible if the needle lies parallel to the slice, i.e. orthogonal to the slice selection gradient. The values obtained before and after the training session were compared to the real position of the needle tip. RESULTS: Mean distance of actual needle tip and tip position as determined from images was 1.8 +/- 2.3 mm in TSE-versus 2.5 +/- 1.2 mm in FFE-images, with the needle length overestimated. After a 15 minute training session the positioning error decreased significantly to 0.2 +/- 1.8 mm for TSE-sequences and to 1.0 +/- 1.8 mm for FFE-sequences. A higher accuracy of tip localization was obtained with TSE sequences. CONCLUSION: In MR guided biopsies using FFE- and TSE-sequences the needle position can be more accurately determined if the reader is familiar with the 12 orthogonal or parallel positions of the needle with respect to B0 and frequency encoding gradient and the corresponding artifacts.
We evaluated the long-term efficacy of laparoscopic Burch urethropexy performed in 35 consecutive women (average age 45.5 yrs, average weight 67.7 kg, average parity 2.3) between May 1992 and July 1994. Preoperative evaluations included cotton swab testing, urinalysis, dynamic urethrocystoscopy, and multichannel urodynamic testing. All subjects had genuine stress incontinence and a positive cotton swab test. Urethropexy was performed with curved needle suturing in 7 women, straight needle suturing in 5, and Stamey needle suturing in 23. Outcome variables were operative time, concomitant surgery, suture needle, length of hospital stay, need for catheterization, and subjective success. Women were divided into groups based on surgical success. Wilcoxon two-sample, chi2, and Fisher's exact tests were used to determine which variables were significantly associated with surgical success. Twenty-five women (71.4%) had concomitant pelvic surgery at the time of urethropexy. Average time of surgery was 190 minutes, length of stay 1 day, and length of time for catheterization 5 days. The cure rate of stress incontinence was 89% at 3 months and 86% at 1 year. At an average follow-up of 30 months, only 68.6% of women reported complete or almost complete cure, 11.4% were improved, and 20% were complete failures. The only variable approaching statistical significance for predicting surgical success was type of suture needle used (p = 0.07), with the Stamey needle group having the highest cure rate. The success rate of laparoscopic Burch urethropexy compares with that of open Burch procedure at 1 year but drops considerably thereafter.
PURPOSE: To test the value of the nonaspiration, or capillary, biopsy technique by experimental comparison with the conventional fine-needle aspiration technique using various needle gauges and lengths. METHODS: On fresh hepatic and renal tissue from five autopsies, multiple biopsy specimens were taken with 20, 22, and 23-gauge Chiba needles of 5, 10, 15, and 20-cm length, using the aspiration technique and the capillary technique. The resultant specimens were graded on the basis of a grading scheme by a cytopathologist who was blinded to the biopsy technique. RESULTS: The capillary technique obtained less background blood or clot which could obscure diagnostic tissue, although not significantly different from the aspiration technique (p = 0.2). However, for the amount of cellular material obtained, retention of appropriate architecture, and mean score, the capillary technique performed statistically worse than aspiration biopsy (p < 0.01). In addition, with decreasing needle caliber (increasing needle gauge) and increasing length, the capillary biopsy was inferior to the aspiration biopsy. CONCLUSION: The capillary biopsy technique is inferior to the aspiration technique according to our study. When the capillary technique is to be applied, preference should be given to larger caliber, shorter needles.
Effective local delivery to the heart remains an obstacle to successful therapeutic application of a number of drugs and biological agents. This study was designed to study and optimize the delivery characteristics of transendocardial intramyocardial (IM) administration, determine myocardial deposition and retention over time, and compare it to transepicardial IM injection. Thirty-nine pigs were used for the study (15 for catheter optimization, 15 for transendocardial IM delivery, and 9 for transepicardial IM delivery). (125)I-Fibroblast growth factor-2 (FGF2) (25 microCi) was used as the prototype molecule. Tissue and myocardial distribution was determined at 1 and 24 h and 7 days. Using 1-h (125)I-FGF2 myocardial deposition as a parameter for delivery efficiency, the optimal needle length and delivery volume for transendocardial based delivery were determined to be 6 mm and 0.1 ml, respectively. Using these parameters for endocardial delivery, (125)I-FGF2 cardiac activity was 18.01 +/- 3.84% of delivered activity at 1 h, 11.65 +/- 5.17% at 24 h, and 2.32 +/- 0.87% at 7 days in ischemic animals. Studies in nonischemic animals produced similar results. For transepicardial delivery, (125)I-FGF2 cardiac-specific activity was 23.14 +/- 12.67% for the 6-mm needle, declining to 12.32 +/- 8.50% at 24 h, and did not significantly differ from values obtained following transendocardial delivery. Thus, optimized transendocardial intramyocardial delivery using Biosense guidance results in efficient delivery of FGF2 to the target myocardium that is comparable with transepicardial delivery, both providing markedly higher myocardial deposition and retention and lower systemic recirculation of FGF2 than intracoronary, intrapericardial, or intravenous delivery. However, myocardial distribution is limited to injection sites.
Eastern white pines (Pinus strobus L.) in their 3rd year of growth photoassimilated 35, 110, 220, or 400 microcuries of (14)CO(2) on a single occasion in the spring when needle expansion was occurring. Once assimilated into organic products and translocated to various sinks, the retained (14)C represented an internal chronic source of ionizing radiation to the plant. About 2.5 months later, the pines were harvested, and the distribution of (14)C activity was determined. In addition, new needle lengths, fresh weights, and rates of processes involving CO(2) exchange were measured.All parameters measured were affected in those pines which initially assimilated 220 or 400 microcuries of (14)CO(2), whereas no significant differences were observed between control plants and those initially assimilating 35 microcuries. Plants incorporating 110 microcuries were intermediate in their responses. The percentage of assimilated (14)C retained by the plants decreased as the initial activity of assimilated (14)C increased, with the losses of (14)C occurring through both respiration and the shedding of needles. The pines which assimilated 35 microcuries of (14)CO(2) retained about 70% of the (14)C; those which assimilated 400 microcuries retained only about 28%. The distribution of the (14)C activity recovered from all the plants was essentially the same; about 65% of the total (14)C recovered was in the new needles and 13% in the roots.
Periocular anesthesia is a proven alternative to retrobulbar anesthesia. A prospective evaluation of 1,000 cases was done to study the advantages of single point, low volume periocular anesthesia. This method is efficacious and has an excellent safety profile. The small needle length and the low volume of injected anesthetic enhance the safety. Supplemental anesthesia was needed in only 0.2% of cases. Chemosis was noted in 12.7%. In no case did surgery have to be postponed because of anesthesia-related complications. We believe this method is superior to other multipoint high volume methods of periocular anesthesia.
In this study, we demonstrate the feasibility to use microneedle arrays manufactured from commercially available 30G hypodermal needles to enhance the transport of compounds up to a molecular weight of 72 kDa. Piercing of human dermatomed skin with microneedle arrays was studied by Trypan Blue staining on the SC side of the skin and transepidermal water loss measurements (TEWL). Passive transport studies were conducted with Cascade Blue (CB, Mw 538), Dextran-Cascade Blue (DCB, Mw 10 kDa), and FITC coupled Dextran (FITC-Dex, Mw 72 kDa). Microneedle arrays with needle lengths of 900, 700 and 550 micro m are able to pierce dermatomed human skin as evident from (a) the appearance of blue spots on the dermal side of the skin after Trypan Blue treatment and (b) elevated TEWL levels after piercing compared to non-treated human dermatomed skin. Microneedles with a length of 300 micro m did not pierce human skin in vitro. Transport studies performed with model compounds ranging from 538 Da to 72 kDa revealed that pretreatment with microneedle arrays enhanced the transport across dermatomed human skin. However, some degradation was also observed for FITC-Dex and DCB. We conclude that assembled microneedle arrays can be used to deliver compounds through the skin up to a molecular weight of at least 72 kDa.
To overcome the skin's barrier properties that block transdermal delivery of most drugs, arrays of microscopic needles have been microfabricated primarily out of silicon or metal. This study addresses microneedles made of biocompatible and biodegradable polymers, which are expected to improve safety and manufacturability. To make biodegradable polymer microneedles with sharp tips, micro-electromechanical masking and etching were adapted to produce beveled- and chisel-tip microneedles and a new fabrication method was developed to produce tapered-cone microneedles using an in situ lens-based lithographic approach. To replicate microfabricated master structures, PDMS micromolds were generated and a novel vacuum-based method was developed to fill the molds with polylactic acid, polyglycolic acid, and their co-polymers. Mechanical testing of the resulting needles measured the force at which needles broke during axial loading and found that this failure force increased with Young's modulus of the material and needle base diameter and decreased with needle length. Failure forces were generally much larger than the forces needed to insert microneedles into skin, indicating that biodegradable polymers can have satisfactory mechanical properties for microneedles. Finally, arrays of polymer microneedles were shown to increase permeability of human cadaver skin to a low-molecular weight tracer, calcein, and a macromolecular protein, bovine serum albumin, by up to three orders of magnitude. Altogether, these results indicate that biodegradable polymer microneedles can be fabricated with an appropriate geometry and sufficient strength to insert into skin, and thereby dramatically increase transdermal transport of molecules.
The nature of intermolecular interactions between halogen atoms, X...X (X = Cl, Br, I), continues to be of topical interest because these interactions may be used as design elements in crystal engineering. Hexahalogenated benzenes (C6Cl(6-n)Br(n), C6Cl(6-n)I(n), C6Br(6-n)I(n)) crystallise in two main packing modes, which take the monoclinic space group P2(1)/n and the triclinic space group P1. The former, which is isostructural to C6Cl6, is more common. For molecules that lack inversion symmetry, adoption of this monoclinic structure would necessarily lead to crystallographic disorder. In C6Cl6, the planar molecules form Cl...Cl contacts and also pi...pi stacking interactions. When crystals of C6Cl6 are compressed mechanically along their needle length, that is, [010], a bending deformation takes place, because of the stronger interactions in the stacking direction. Further compression propagates consecutively in a snakelike motion through the crystal, similar to what has been suggested for the motion of dislocations. The bending of C6Cl6 crystals is related to the weakness of the Cl...Cl interactions compared with the stronger pi...pi stacking interactions. The triclinic packing is less common and is restricted to molecules that have a symmetrical (1,3,5- and 2,4,6-) halogen substitution pattern. This packing type is characterised by specific, polarisation-induced X...X interactions that result in threefold-symmetrical X3 synthons, especially when X = I; this leads to a layered pseudohexagonal structure in which successive planar layers are inversion related and stacked so that bumps in one layer fit into the hollows of the next in a space-filling manner. The triclinic crystals shear on application of a mechanical stress only along the plane of deformation. This shearing arises from the sliding of layers against one another. Nonspecificity of the weak interlayer interactions here is demonstrated by the structure of twinned crystals of these compounds. One of the compounds studied (1,3,5-tribromo-2,4,6-triiodobenzene) is dimorphic, adopting both the monoclinic and triclinic structures, and the reasons for polymorphism are suggested. To summarise, both chemical and geometrical models need to be considered for X...X interactions in hexahalogenated benzenes. The X...X interactions in the monoclinic group are nonspecific, whereas in the triclinic group some X...X interactions are anisotropic, chemically specific and crystal-structure directing.
The Swiss Federal Office of Public Health and the Swiss Advisory Board on Immunisation recommended that universal vaccination against hepatitis B be introduced in January 1998. The target population for immunisation are youngsters between 11 and 15 years of age. This recommendation does not preclude ongoing selective vaccination of individuals in high risk groups, nor the routine immunisation of individuals younger or older than the target age (if needed). Injections should be given in the deltoïd area and needle length is critical to ensure proper resorption of the antigen and adequate immune response. Three doses are recommended at times 0, 1 month and 6 months with no booster dose. The time interval between the second and third dose should not be shorter than 2 months but can be longer than 5 months. Vaccination initiated with one commercial brand can be completed with a different brand. The simultaneous administration of immune globulin with the initiation of vaccination and the measurement of serum antibodies after completion of vaccination are unnecessary.