Microwave: practical cost-effective method for sterilizing urinary catheters in the home

We used a standard microwave oven to sterilize red rubber catheters used for intermittent self-catheterization. Catheters were incubated for sixty minutes in a suspension of microorganisms isolated from the urine of patients with urinary tract infections. For each trial, 6 catheters were removed from their respective suspensions, placed in separate plastic freezer bags, distributed evenly in a microwave oven (avoiding cold spots), and microwaved simultaneously for twelve minutes. A control catheter was not microwaved. Two strains of each microorganism were tested. The urinary isolates were Escherichia coli, Klebsiella sp., Proteus sp., Enterobacter sp., Pseudomonas sp., Streptococcus sp., Staphylococcus sp., and Candida sp. In each experiment, all 6 catheters were sterilized. Repeat sterilization in the microwave oven did not affect the integrity of the catheters or the plastic bags. A water heat sink of constant volume was employed. A home microwave oven may be used as a method to sterilize red rubber catheters for reuse with a recommended time of twelve minutes at full power. This technique makes aseptic intermittent self-catheterization a practical possibility.     

Microwave sterilization: a method for home sterilization of urinary catheters

A standard microwave oven has been used to sterilize catheters used for intermittent self-catheterization. Catheters were incubated for 60 minutes in a suspension of microorganisms isolated from the urine of patients with urinary tract infections. Each catheter was removed from the suspension, placed in a paper bag and microwaved for 0 to 30 minutes. A control catheter was not microwaved. We tested 42 strains of microorganisms to determine the minimum microwaving time needed to sterilize the catheters. Representative urinary isolates of Escherichia coli, and Klebsiella, Proteus, Enterobacter, Pseudomonas, Staphylococcus, Streptococcus and Candida species were tested. Mean sterilization time for all strains was 13.0 minutes (standard deviation +/- 5.7 minutes), with a range of 4.0 to 28.6 minutes. Repeat sterilization in the microwave oven did not affect the integrity of the catheter. A water heat sink of constant volume was required. A home microwave oven may be used as a method to sterilize red rubber catheters for reuse. This technique makes aseptic intermittent self-catheterization a practical possibility.     

The physical and antimicrobial effects of microwave heating and alcohol immersion on catheters that are reused for clean intermittent catheterisation

INTRODUCTION: Due to worldwide different health insurance policies, patients are often forced to reuse the catheters when performing Clean Intermittent Catheterisation (CIC). We have compared the physical qualities and the antimicrobial effects of two methods of reusing catheters: microwave heating and storage of the catheters in a 70% alcohol solution. The studies were performed during different lengths of time. MATERIALS AND METHODS: Three types of catheters (a standard polyvinylchloride catheter, a special polyvinylchloride catheter with flexible Ergothan tip and a prelubrified catheter), normally intended for single use, were submitted to the effect of a microwave oven (Multitech 215 High Grade and Whirlpool M220 750 W and 1000 W with rotating plate) or preservation in a 70% alcohol solution. To study the effects of microwave heating, a recipient of water was placed in the oven to spread the microwaves and to absorb the heat. The catheters were placed in a resealable plastic bag (Ziploc. To study the effects of preservation in a 70% alcohol solution, the catheters were immerged in the solution for different lengths of time. Thereafter were the physical qualities of the catheters evaluated by using the technique of Differential Scanning Calorimetry (DSC). The antimicrobial effect of the method was evaluated after grafting the catheters with pathogenic E. coli, P. aeruginosa or S. aureus strains. RESULTS: Microwave heating up to 12 minutes at 750 W caused only minimal changes in the physical qualities of all the catheters. However, there was only an antimicrobial effect of the microwave heating on E. coli and not on P. aeruginosa or S. aureus. If the catheter remained longer than 45 minutes in a 70% alcohol solution, the physical qualities of the catheter changed either minimal in the special polyvinylchloride catheter with flexible Ergothan top but changed significantly in the prelubrified catheter). However, already after 5 minutes of immersion in the 70% alcohol solution there was a complete antimicrobial effect on E. coli, P. aeruginosa and S. aureus in all catheters. CONCLUSIONS: It should be recommended to patients on CIC to use a sterile packed and not previously used catheter. In this study we have shown that immersing the catheters in a 70% alcohol solution during 5 minutes can effectively disinfect the catheter without jeopardising the physical qualities. Thereafter, the catheters could be placed in a resealable (e.g. Ziploc bag without being rinsed under water, in order that the few drops of alcohol cause alcohol vapours within the closed plastic bag and maintain the antimicrobial effect.     

Distal forearm tourniquet for hand surgery

To evaluate the usefulness of the tourniquet placed at the distal forearm, 30 patients were operated with the tourniquet set at the distal forearm using nerve-block anaesthesia. Pain during surgery, flexion of the fingers, bloodless field, and general complications during surgery and 18 months thereafter were recorded. The mean time of ischemia was 19.6±7.5 (10–50) min. A bloodless field was achieved in all cases, and pain during operation was low. Flexion of the fingers were found in most cases but was reducible and not annoying for the surgeon. There were no serious complications during surgery or at follow-up. The tourniquet placed at the distal forearm is painless, safe, and useful in hand surgery.

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Résumé Pour évaluer lutilité du garrot placé à la partie distale de lavant-bras, 30 malades ont été opérés avec le garrot dans cette position et une anesthésie par bloc nerveux. La douleur pendant la chirurgie, la flexion des doigts, l exsanguinité du champ opératoire et les complications générales pendant la chirurgie et 18 mois ensuite ont été enregistrées. Le temps moyen dischémie était de 19,6±7,5 min (10–50). Un champ exsangue a été obtenu dans tous les cas. La douleur pendant lopération était faible. La flexion des doigts a été notée dans la plupart des cas, mais était réductible et ne gênait pas le chirurgien. Il ny avait pas de complication sérieuse. Seulement une blessure nerveuse a été suspectée. Le garrot placé à la partie distale de lavant-bras est indolore, sûr et utile dans chirurgie de la main.

     

Variability in catheter microwave sterilization techniques in a single clinic population

PURPOSE: We designed a survey to assess the microwave sterilization technique practiced by patients at our clinic who perform clean intermittent catheterization. MATERIALS AND METHODS: A 23-question survey addressing urinary catheter use and home sterilization techniques was mailed to 129 patients. A followup survey was mailed to 47 respondents who reported using a microwave oven to sterilize the catheters to assess the microwave technique further. RESULTS: Of the 129 initial surveys 84 (64%) were returned, while 40 (85%) of the 47 followup questionnaires on microwave sterilization were returned. All patients surveyed have used clean intermittent catheterization for at least 1 year and 75% have used it more than 5 years. Of the respondents 80% perform clean intermittent catheterization 4 to 5 times daily, although sterilization frequency varies from daily to less than once weekly. Of the respondents 71% reported no difficulty with microwave sterilization, although 31 (63%) reported a history of catheter melting during microwaving. Of the respondents 35% reported using a rotation table, all used a heat sink containing 1/2 to 4 cups of water, 39% used 500 to 1,000 W., 37% used greater than 1,000 W., 73% set the microwave for 6 minutes, others set it for 3 to 30 minutes and 98% used a power setting described as high, full, 10 or 100%. CONCLUSIONS: Significant variation exists in the cleaning and sterilizing techniques used by our patients, although they were given uniform written and verbal instructions. It is unclear from the data in the literature how this variation affects sterilization.     

Continuous venovenous haemofiltration in the acute treatment of inborn errors of metabolism

The accumulation of toxic metabolites in children with inborn errors of metabolism may cause acute metabolic crises and result in long-term neurological dysfunction or death. Peritoneal dialysis often provides insufficient clearance to protect against these complications, while intermittent haemodialysis cannot prevent reaccumulation of metabolites between dialysis sessions. We describe the use of continuous venovenous haemofiltration (CVVH) or haemodiafiltration (CVVHD) in three infants with maple syrup urine disease (MSUD) and one child with carbamyl phosphate synthetase (CPS) deficiency. All children with MSUD had a satisfactory reduction in branchedchain amino acids within 24 h of onset of haemofiltration, and are now neurologically normal. The child with CPS deficiency had an ammonia level of <100 mol/l within 24 h of onset of therapy, but died 3 days later from unrelated cardiovascular complications. Complications of the therapy included the clotting of one haemofilter and the replacement of two vascular access catheters per patient on average per therapy. Two patients required blood transfusion. We report the successful use of CVVH and CVVHD in the acute management of metabolic crises associated with inborn errors of metabolism, and believe that these may be the optimal techniques for the acute clearance of toxic metabolites.     

MICROWAVE STERILIZATION OF POLYETHYLENE CATHETERS FOR INTERMITTENT SELF-CATHETERIZATION

A standard household 650 W microwave oven was used to sterilize polyethylene catheters of the type used for intermittent self-catheterization. The Catheters were infected with Proteus sp. bacteria and microwaved at 650 W for periods of 2, 4, 6 and 8 minutes. The effect of microwaving was assessed by determining the resultant colony counts following catheter culture. It was determined that 6 minutes of microwaving were required to achieve sterility. It is suggested that use of a microwave oven is a reliable and cost-effective method of sterilizing polyethylene catheters for intermittent self-catheterization.     

Stoß- und schlagbelastung des menschlichen schienbeins im drehversuch

Zusammenfassung Die menschliche Tibia wurde bei mittlerer und schneller Drehgeschwindigkeit bis zum Bruch des Knochens belastet. Die Ergebnisse der Zehntel- und Hundertstelsekundenfraktur werden mit denen bei langsamer Drehung (Sekundenfraktur) verglichen.Beim Drehstoß ( = 236°/sec) steigen die Frakturdrehmomente durchschnittlich um 17%, beim Drehschlag ( = 597°/sec) um 25% gegenüber der langsamen Drehung ( = 6°/sec). Die Elastizitätsgrenze, die die Verletzungsgrenze der Tibia darstellt, zeigt jeweils einen noch etwas höheren Anstieg. Die menschliche Tibia ist also gegenüber Stößen und Schlägen weniger empfindlich als gegenüber langsamen Belastungen, bei Drehung noch mehr als bei Biegung. Der Durchmesser des Schienbeinkopfes korrelierte im Vergleich zu zahlreichen weiteren Parametern am besten mit den Bruchwerten. Energieaufnahme, Form, Lage und Länge der Fraktur änderten sich auch bei schneller Drehung nicht, der Frakturdrehwinkel nahm bei Schlagbeanspruchung leicht ab.Für die Verletzungsprophylaxe beim alpinen Skilauf sind bei kurzer Krafteinwirkung die Trägheitsmomente des gesamten Beines zu berücksichtigen und erhöhen die o. g. Werte der Verletzungsgrenze erheblich.Aus den Ergebnissen werden Folgerungen für den Schutz vor typischen Skiverletzungen durch die Skibindung abgeleitet und können dazu beitragen, die passive Sicherheit beim Skilauf weiter zu erhöhen.

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Hit and blow endurance of the human tibia in torsion testing

Summary Whole human tibiae were fractured with rapid loading rates of tenths and hundreds of a second for torsional fracture. Results were compared with data of experiments in slow loading during seconds.Loading time of 100 msec ( = 236°/s) increased the mean maximum torque of 17%, loading time of 10–40 msec ( = 597°/s) showed increase of 25%. In dynamic twisting the applied torque at the elasticity threshold, which represents the injury threshold of the tibia, has relatively higher values than the data at failure. The best correlation to the maximum torque exists at the frontal diameter of the tibia head.In dynamic twisting energies, site, figuration and length of fracture did not differ from those in quasistatic twisting procedures. With loading time of hundreds of a second the angle of fracture diminished.To prevent injuries in alpine skiing it is important to consider inertial effects of the whole leg in dynamic twisting. These effects raise the values of injury threshold distinctly. Practical conclusions are drawn from the results to get better passive safety in alpine skiing by perfecting release bindings.

     

Collagen distribution in human membranous glomerulonephritis

In membranous glomerulonephritis (MGN), thickening of the glomerular basement membrane (GBM) is partly due to the accumulation of basement membrane material between and around immune deposits located on the epithelial aspect of the GBM. We investigated the distribution of type IV collagen chains (1/2, 3, 4, 5, 6) and of types I, III, V, and VI collagen in the glomeruli from 16 patients, by indirect immunofluorescence in 13 and the high-resolution immunogold technique in 6. No changes were detected in stage I MGN. The spiky projections of the GBM in stage II MGN and the basement membrane layers encircling immune deposits in stage III contained the 3, 4, and 5 chains of type IV collagen. In contrast, the 1/2 chains of type IV, as well as type VI collagen accumulated in the subendothelial aspect of the GBM. No significant staining for types I, III, and V collagens or for the 6 chain of type IV collagen was detected. The results show that, as in the normal glomeruli, the different chains of type IV collagen are not co-distributed in the glomerular extracellular matrix in MGN. They also indicate that type IV collagen chains and type VI collagen play an important role in the thickening of the GBM in human MGN.     

Enolase isozymes in seminoma

Summary We determined concentrations of and -enolases in normal testis and in seminoma tissues by enzyme immunoassay. Concentrations of -enolase were 4,170±2,040 ng/mg protein in normal testis (n = 8) and 8,140±4,480 ng/mg protein in seminoma (n = 8). Concentrations of -enolase in seminoma (460±571 ng/mg protein) were significantly higher than those of normal testis (59±15 ng/mg protein). Immunohistochemistry showed positive tumor cells for -enolase in 6 of 8 seminoma cases (75%). Serum -enolase levels were elevated (> 6.0 ng/ml) in 9 of 12 patients (75%) with seminoma: 60% of stage I, and 100% of stages II and III. In 10 patients treated by surgical excision and chemotherapy, serum -enolase was significantly reduced after the treatment. These findings indicate that elevated serum -enolase is derived from enhanced -enolase in seminoma tissues, and that serum -enolase could be a useful biomarker for staging and monitoring clinical course in patients with seminoma.     

In vitro evaluation of percutaneous drainage catheters: Flow related to connections and liquid characteristics

Purpose

To evaluate the effect of catheter connections on drainage catheters’ flow rate.

Identification of α1-adrenoceptor subtypes in the dog prostate

Summary The ₁-adrenoceptor subtypes of dog prostate were characterized in binding and functional experiments. In saturation experiments, [³H]prazosin bound to ₁-adrenoceptors with high affinity. In the displacement experiments, unlabelled prazosin and WB4101 biphasically inhibited the binding of 400 pM [³H]prazosin, suggesting the presence of at least two distinct affinity sites for prazosin or WB4101. The proportion of high-affinity sites was approximately 10%. HV723 also recognized two distinct affinity sites but the proportion of high-affinity sites was approximately 20%. From these results the presence of three distinct ₁-adrenoceptor subtypes was suggested: presumably subtypes _1A (high affinity for prazosin and WB4101), _1N (high affinity for only HV723) and _1L (low affinity for the three antagonists) according to the recently proposed ₁-adrenoceptor subclassification. The density of subtype _1L was much higher than that of subtypes _1A and _1N subtypes. In the functional experiments, prazosin, WB4101 and HV723 competitively antagonized the contractile response to noradrenaline with low affinities close to those estimated for the _1L subtypes. These results suggest that the contractile response to noradrenaline in the dog prostate is mediated predominantly through _1L subtype -adrenoceptors.     

Use of a pericardial fat pad flap for preventing bronchopleural fistula: An experimental study focusing on the angiogenesis and cytokine production of the fat pad

An experimental study was conducted to determine whether pericardial fat tissue could induce neovascularization and produce cytokines related to tissue repair. Neovascularization was examined using chick chorioallantoic membranes. Pieces of pericardial fat tissue, omentum, and intercostal muscle were individually placed on a number of chorioallantoic membranes and neovascularization induced by each material was assayed 6 days after the implantation. The intensity of neovascularization was in the order of pericardial fat omentum > muscle. Cytokines, such as interleukin 1 (IL-1) and , tumor necrosis factor- (TNF), interferon- (IFN-), and interleukin 6 (IL-6) were assayed in a culture supernatant of pericardial fat tissue. The latter was obtained 24h after the addition of lipopolysaccharide (LPS) following various incubation times. All cytokines other than IFN are known to play a part in tissue repair, whereas IFN is negatively related to tissue repair because it inhibits fibroblast growth. The pericardial fat tissue incubated with LPS produced a certain amount of IL-1 on day 1, and TNF on days 1 and 8, whereafter these values decreased to an undetectable level. Irrespective of the addition of LPS, a large amount of IL-6 was observed in the supernatant of pericardial fat tissue and it was detectable until day 29. On the contrary, INF was not detected at any assay time. These observations suggest that a pericardial fat pad flap could possibly be beneficial in the prevention of bronchopleural fistula after pulmonary resection.     

Elevated concentrations of the β-subunit of S100 protein in renal cell tumors in rats

Concentrations of and -subunits of S100 protein (S100- and S100-) in rat kidney neoplasms, including renal cell and mesenchymal tumors, were determined using a highly sensitive enzyme immunoassay, and both types immunohistochemically localized in tissue sections. Concentration of S100- in each histological type of rat tumor were lower than in normal kidney, whereas levels of S100- (mean±SE: 29.7±14.2 ng/mg protein, n=15) in renal cell tumors were significantly higher than in normal kidneys (0.55±0.06 ng/mg protein, n=7), or mesenchymal tumors (1.21±0.43 ng/mg protein, n=9). In normal rat kidney tissues S100- was immunohistochemically positive in epithelial cells of the distal tubules, the thin limbs of loops of Henle, and the collecting ducts. No appreciable immunostaining for S100- was found in any nephron segment. Both S100- and S100- were positive for renal cell tumors, indicating new appearance of the latter during renal carcinogenesis in rats.     

Effects of Nd-YAG laser on platelet function in vitro: A comparative study using the spectraprobe, ‘hot tip’ and bare fibres

The effects of Nd-YAG laser irradiation on platelet function in vitro were studied using platelet rich plasma obtained from the blood of healthy volunteers. Laser delivery was effected via the bare optical fibre, thermal hot tip fibre and spectraprobe and the effects of these probes on platelet function were compared. Fall in platelet count and mean platelet volume (MPV) were proportional to increasing energy delivery with all three probes, the effect being maximal with the spectraprobe, moderate with the hot tip and least with the bare optical fibre. A significant decrease in percentage aggregation of platelets in response to added ADP, collagen and ristocetin with increasing energy delivery was also observed with all three probes. The formation of preformed aggregates, however, showed an increase proportional to energy delivery with all three probes.The differential effects of the various probes used in this study on platelet function may enhance our understanding of the complex role played by platelets in the pathogenesis of complications such as arterial thrombosis and re-occlusion after laser angioplasty.     

TNFα-stimulated gene product (TSG-6) and its binding protein, IαI, in the human intervertebral disc: new molecules for the disc

Inflammation and irritation of the nerve roots has been indicated as an important factor in the pain associated with symptomatic disc herniations. Tumour necrosis factor (TNF) is now believed to be involved in this pathway. TNF causes connective tissue cells in culture to synthesise a glycoprotein, TNF-stimulated gene-6 (TSG-6). TSG-6 is found in inflammatory diseases of related connective tissues, such as articular cartilage in rheumatoid arthritis, but is not present in unaffected individuals. In order to determine if TSG-6 occurred in intervertebral disc (and cartilage endplate), we have investigated the presence of TSG-6 and its binding protein, inter--inhibitor (II), in 58 herniated and 15 non-herniated discs. Immunostaining for the cytokines, IL-1, IL-1 and TNF, has also been carried out. We have demonstrated that both TSG-6 and II occur commonly in human intervertebral disc matrix with at least some TSG-6 in 98% of discs studied and II in all of them. Staining for TSG-6 was greatest in herniated discs, particularly close to blood vessels. II immunostaining was frequently widespread throughout the disc but there was little in the cartilage endplate. It has been proposed that these molecules have widespread effects, including extracellular matrix stabilisation, down-regulation of the protease network and reduction of inflammation. Hence, the occurrence of TSG-6 and II in disc tissue could have implications in the aetiopathogenesis and future therapeutics of intervertebral disc disease.     

Biological activity of tissue flaps in the treatment of complicated irradiation wounds

Within the last ten years, 79 patients were treated for 114 chronically contaminated, intractable irradiation wounds using various methods of the modern plastic surgery. Radical excision of the devitalised contaminated tissue has been impracticable in 25 cases due to the risk of life-threatening complications or significant functional loss. Different types of flaps such as cutaneous, fasciocutaneous, musculocutaneous, split muscle, isolated vascularised fascia and greater omentum have been used. Despite the incomplete excision, 84% of wounds healed primarily. The essential factor for good wound healing seems to be the biologic activity (BA) of the flap's deep tissue layer that directly contacts the wound bed. BA includes density of the vascular net, ability of neovascularisation, plasticity and specific immunological capacities. It seems to be possible to classify the flaps according to the BA level. Tissue defects in which the chances for radical debridement are poor need the highest BA level in the flap reconstruction.Presented to the European Congress on Wound Healing and Skin Physiology, Bochum, Germany, 1992     

Comparison of adrenoceptor subtype expression in porcine and human bladder and prostate

We have quantified and characterized ₁-, ₂-and -adrenoceptor subtypes in porcine bladder detrusor and bladder neck, human bladder detrusor, and porcine and human prostate. ₁-, ₂- and -adrenoceptor were identified in radioligand binding studies using [³H]prazosin, [³H]RX 821002 and [¹²⁵I]iodocyanopindolol, respectively, as the radioligands. In porcine male and female detrusor and bladder neck and male prostate, adrenoceptors were detected in the order of abundance > _{2 1} (not detectable), with no major differences between the sexes or between detrusor and bladder neck. In human detrusor and prostate the order of abundance was > _{2 1} (not detectable) and ₁ > ₂. respectively. The ₂-adrenoceptors in all tissues were homogeneously of the _2A-subtype as evidenced by competition binding studies with yohimbine, prazosin, ARC 239 and oxymetazoline. The -adrenoceptors represented a mixed population with a dominance of the ₂-subtype in all tissues as demonstrated by competition binding with ICI 118,551 and CGP 20,712A. We conclude that pigs may be a suitable model for studies of detrusor function with respect to adrenoceptor expression. They may be less suitable for studies of bladder neck or prostate function.     

Mechanical loading of peripheral nerves during remobilisation of the affected member after end-to-end anastomosis

Summary Our study involved simulating end-to-end neurorrhaphy of the sciatic nerve in a number of rabbits and analysing in vivo the mechanical loads acting on the nerve while the affected member was being remobilised. We found both the suture and mobilisation loads to be related to the size of the nerve defect. In each case, traction force, strain, and stress were proportional. The effect which these experimental findings may have on the future use of flexing neighbouring joints as a manipulative measure to achieve a tension-free nerve suture will be discussed.     

Comparison between the Klemetti index and heel DXA BMD measurements in the diagnosis of reduced skeletal bone mineral density in the elderly

Osteopenia/osteoporosis affect many elderly people and might not be detected until symptoms of fractures occur. Early detection of osteopenia/osteoporosis is important and would allow preventive measures and treatment. Access to screening for osteopenia/osteoporosis is often limited, whereas panoramic radiography is commonly used in dentistry. The aim of this study was to determine the validity of the Klemetti index (KI), measured on panoramic radiographs, in the diagnosis of osteopenia/osteoporosis as defined by a bone mineral density (BMD) measurement below –1.5 standard deviations (SDs) of a community based sample. In total, 211 consecutive participants (102 men and 109 women) 60–96 years in the SNAC–Blekinge study (Swedish National Study on Ageing and Care) underwent bone densitometry [by dual-energy X-ray absorptiometry (DXA)] of both heels. A panoramic radiograph was taken of each participant, and mandibular cortex on a panoramic radiograph was classified as 0 or normal (even and sharp endosteal margin), 1, moderately eroded (evidence of lacunar resorption or endosteal cortical residues), or 2, severely eroded (unequivocal porosity). From logistic regression, the odds ratio of having a BMD measurement below –1.5 SD was 8.04 (95% CI 2.39 to 27.12, P<0.001) in the osteopenic (KI category 2), compared with the normal group (KI categories 0 and 1). Receiver operating characteristic (ROC) curve analysis was used to measure the validity of the KI indicating osteopenia (KI category 2) in predicting reduced BMD. This point provided a sensitivity of 50% and a specificity of 89%. Positive and negative predictive values were 21% and 97%, respectively. There were 87% correctly classified subjects. The area under the ROC curve was 0.64. The present study demonstrated that a negative finding (KI category <2) is highly predictive of the absence of osteopenia/osteoporosis as defined by the DXA measurements.