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Vacine cold chain assessments conducted in various parts of the world indicate that maintaining equipment at the temperature range recommended by the World Health Organization (WHO) is not always observed. It has been also the case that staff rather prioritize protecting vaccine from heat damage, thus often exposing vaccines to freezing temperatures. As a result, inadvertent freezing of vaccines is a largely overlooked problem all over the world. In a recent systematic review, comparison of the occurrence of freezing temperatures during storage and transport were found to be a global problem occurring both in the resource-rich as well as the resource-limited settings. A vaccine cold chain temperature monitoring study was conducted using standard WHO study protocol with the objective to document potential problems and to identify appropriate control measures. Multiple temperature monitoring devices were used in the study to evaluate user friendliness of these devices and staff attitudes towards them. In general, majority of the time, temperatures were kept between recommended temperature range of 2–8 °C. Temperature variation got wider when products moved from 3PL Laboratory to service points. The wider variation is found at the service points. High temperature excursions were observed or short periods of time while exposures to freezing temperatures were more both higher in number and duration, however, shake test with these vaccines indicated no freeze damage. 91% of staff believed that they did not have the necessary tools to detect if a vaccine had been damaged by a temperature excursion outside the 2–8 °C range, and all staff believed that inclusion of such devices (e.g. vaccine vial monitor) in the system would improve cold chain operations as they have became aware of problematic areas through this study.

Aluminum-adjuvanted vaccines are freeze-sensitive products that require attentive cold chain adherence. Freeze/thaw events can be tested using "The World Health Organization Shake Test", a qualitative test whereby a vial from the batch suspected to have been frozen is checked to infer whether the whole batch has been frozen. In this paper, we present a noninvasive and quantitative method to detect whether a vial of liquid vaccine has experienced freeze/thaw using the water proton transverse relaxation rate by Nuclear Magnetic Resonance relaxometry (wNMR relaxometry). Importantly, wNMR relaxometry does not compromise the vial's integrity so the analyzed vial can be used for vaccination if it meets the quality specifications. Vial-to-vial variability in freezing susceptibility within a single carton of vaccine vials was also detected, both by visual observation and concurrently by wNMR relaxometry. This variability brings into question the practice of using one or a few vials in a batch of vaccines to infer about the quality of the whole batch.

Nettle is a cellulose plant fiber which enormously exists in tropical wasteland areas around the world. Various researchers throughout the world have studied the characteristics of nettle in different forms such as fibers, yarns and fabrics. In the present work, 100% nonwoven nettle fibrous assembly has been produced using needle punching machine and investigated for its suitability in oil spill cleanup applications. The oil sorption capacity of 100% needle-punched nonwoven nettle fibrous assembly against crude oil and diesel engine oil was 22.39 g/g and 19.29 g/g, respectively. Further, nonwoven nettle fibrous assembly was also subjected to tests such as reusability, burning tests, temperature test, shake test and extraction test. These test results confirm that 100% needle-punched nonwoven nettle fibrous assembly can be effectively used for oil spill cleanup applications.

Accidental exposure of a vaccine containing an aluminum-salt adjuvant to temperatures below 0°C in the cold chain can lead to freeze damage. Our study evaluated the potential for freeze damage in a licensed aluminum-salt-containing protein-D-conjugated pneumococcal vaccine (PHiD-CV; Synflorix, GSK) in conditions that included static storage, single subzero-temperature excursions, and simulated air-freight transportation. Several parameters were assessed including freezing at subzero temperatures, aluminum-salt-particle size, antigen integrity and immunogenicity in the mouse. The suitability of the WHO's shake test for identifying freeze-damaged vaccines was also assessed. During subzero-temperature excursions, the mean temperatures at which PHiD-CV froze (−16.7°C to −18.1°C) appeared unaffected by the type of vaccine container (two-dose or four-dose vial, or single-dose syringe), vaccine batch, rotational agitation, or the rate of temperature decline (−0.5 to −10°C/hour). At constant subzero temperature and in simulated air-freight transportation, the freezing of PHiD-CV appeared to be promoted by vibration. At −5°C, no PHiD-CV sample froze in static storage (>1 month), whereas when subjected to vibration, a minority of samples froze (7/21, 33%) within 18 hours. At −8°C with vibration, nearly all (5/6, 83%) samples froze. In these vibration regimes, the shake test identified most samples that froze (10/12, 93%) except two in the −5°C regime. Nevertheless, PHiD-CV-antigen integrity appeared unaffected by freezing up to −20°C or by vibration. And although aluminum-salt-particle size was increased only by freezing at −20°C, PHiD-CV immunogenicity appeared only marginally affected by freezing at −20°C. Therefore, our study supports the use of the shake test to exclude freeze-damaged PHiD-CV in the field.

Background The morbidity and mortality of hyaline membrane dis- ease (HMD) are quite high due to delayed diagnosis and intervention. Commonly, HMD occurs in preterm infants with surfactant deficiency because of lung immaturity. Lung maturity test could be performed using biochemical, biophysical, and amniotic fluid turbidity test. Objective To find out HMD prevalence and the value of shake test and lamellar body concentration in diagnosing HMD in preterm infants. Methods This was a cross-sectional study carried out at Hasan Sadikin Hospital Bandung on preterm infants born during October- December 2001. The shake test was performed using gastric fluid and amniotic fluid while the lamellar body concentration was per- formed using amniotic fluid. Results During the 3-month period, 571 infants were born, of 64 (11.2%) preterm infants, only 41 (64%) fulfilled the inclusion crite- ria; among those preterm infants, 14 (34%) suffered from respira- tory distress and 7 suffered from HMD (prevalence 17%). All HMD cases occurred in infants less than 32 weeks for gestational age. In 7 preterm infants with HMD, the shake test of gastric fluid ob- tained by lavage showed negative results in 3 and +1 in 4 infants; while the shake test of amniotic fluid revealed negative result in 5 and +1 in 2 infants. Lamellar body concentration of amniotic fluid was ≤18,000/ml in all HMD infants. Among three infants less than 32 weeks for gestational age who did not suffer from HMD, +1 shake test of gastric fluid was found in 2 infants and +2 in 1 infant; while shake test of amniotic fluid showed negative result in 1 infant and +1 in 2; the lamellar body concentration of amniotic fluid was ≤18,000/ml in 2 infants and >18,000/ml in 1 infant. Conclusions We concluded that HMD occurred in 17% of preterm infants. The shake test of gastric and amniotic fluids revealed nega- tive or +1 results whereas lamellar body concentration had value of less than or equal to 18,000/mL. More extensive studies are warranted to assess the validity (sensitivity, specificity and predic- tive values) of these measurements

Introduction: The potency of vaccines depends on maintaining the cold chain, that is, a prescribed temperature range during distribution from manufacture to use. The paramedical staff of any hospital plays a pivotal role in cold chain maintenance. Hence, the study aims to assess knowledge and practice of cold chain maintenance of vaccines by paramedical staff. Materials and Methods: A cross-sectional questionnaire-based study was conducted among paramedical staff in a tertiary health care of western Maharashtra, from June 15, 2019, to August 30, 2019. The data were collected using interview schedule. Results:A total of 115 paramedics were enrolled. The final data analysis was done on 91 respondents. Participants' knowledge about maintenance of refrigerators with respect to place of vaccine storage (54; 59.34%), temperature recording in a day (54; 59.34%), and preferable place of deep freezer (62; 68.13%) was satisfactory. A total of 42 (46.15%) participants had knowledge about shake test; however, only 38 (41.75%) participants knew about demonstration of shake test, suggesting that awareness about testing the frozen vaccine was poor among paramedical staff. Full form and use of vaccine vial monitor (VVM) in participants were satisfactory, being 70 (76.92%) and 59 (64.83%), respectively. Participant's knowledge about correct site and route of administration of vaccines were satisfactory. Conclusion: The study demonstrates the gap in knowledge in cold chain maintenance of the paramedical workers. Regular training may be conducted for the paramedical workers to improve their understanding of the cold chain management.

We compared urine microscopy and dipstick results for urine foam from 59 children in a Schistosoma haematobium-endemic area in a blinded manner. The sensitivity and specificity, respectively, for diagnosing S. haematobium compared with microscopy was: 74% and 72% for the shake test; 61% and 97% for microscopic hematuria; and 43% and 83% for proteinuria. When >17 eggs/10 mL urine was detected on microscopy, the sensitivity and specificity, respectively, were: 100% and 72% for the shake test; 90% and 97% for microscopic hematuria; and 80% and 83% for proteinuria. Urine foam height >34 mL was significantly more likely to have S. haematobium eggs detected on microscopy (P = 0.001) than urine foam ≤34 mL, indicating that S. haematobium-infected urine is associated with increased urine foam.

Objectives To assess depth of cure (DOC), degree of conversion (DC), and flexural strength (FS) of several resin composites with low-stress behavior. Methods SonicFill (Kerr), SureFil ® SDR™ (Dentsply), everX Posterior (GC), Kalore (GC), and Filtek Silorane (3M ESPE) were tested. DOC was measured with the Acetone Shake test. DC was assessed with Fourier Transform Infra-Red spectroscopy on top and at the bottom of 4 mm-thick disk-shaped specimens. Bottom to top ratios of DC percentages were calculated. FS was evaluated with the Three-Point Bending test. DOC, DC, and FS data were statistically analyzed. Results SureFil ® SDR™ and everX Posterior achieved significantly greater DOC than Kalore and Filtek Silorane. Also, SonicFill had significantly greater DOC than Filtek Silorane. Mean top DCs ranged between 71.46% and 52.44%. Kalore and everX Posterior had significantly lower top DCs than the other materials. Mean DC values at 4 mm ranged largely from 57.95% to 6.82%. Kalore and Filtek Silorane had the lowest values of bottom DC and the difference was statistically significant. EverX Posterior and SonicFill recorded significantly higher FSs than the other materials. Significance SureFil ® SDR™ and everX Posterior exhibited DOC over 4 mm, the maximum thickness recommended for bulk placement, while SonicFill recorded DOC values very close to the 4 mm threshold. SonicFill achieved the highest DC at the irradiated surface, as well as at 4 mm depth. SureFil ® SDR™ demonstrated similarly uniform curing through the bulk increment. All the tested composites complied with the requirements of FS established by ISO 4049/2009.

The need for the practice of dentistry in the digital (CAD/CAM) technologies have initiated the emergence of dental laboratories as a separate and independent legal entities. The choice of a strategy for the development of these laboratories is aimed at ensuring the achievement of the main goals in the long term. It is established that the type of innovation in terms of 'Shake test' J. Daya, in these organizations can be designated as an option 'C' - a strategy of gradual conquest of the market. The main components of the development are: work with staff, information support, financial optimization; material and technical support, marketing activities, organizational and legal support, the formation of the quality system.Потребность практической стоматологии в цифровых (CAD/CAM) технологиях изготовления зуботехнических конструкций инициировала появление зуботехнических лабораторий как самостоятельных юридических лиц. Выбор стратегии развития этих лабораторий нацелен на принятие решений, призванных обеспечить координированное и упорядоченное достижение основных целей в долгосрочном периоде. Установлено, что тип инноваций по показателям Шейк-теста Дж. Дэя в ряде этих организаций можно обозначить как вариант 'С' - стратегию постепенного завоевания рынка, когда основными компонентами развития являются работа с персоналом, информационное обеспечение, финансовая оптимизация, материально-техническое обеспечение, маркетинговая деятельность, организационно-правовое обеспечение, формирование системы качества.

This study was planned to evaluate structural damages in adsorbed vaccines affected by freezing using scanning electron microscopy and X-ray analysis of the elements. Randomly selected 42 vials of eight different types of WHO pre-qualified adsorbed freeze-sensitive vaccines from 10 manufacturers were included in the study. Vaccines were kept at 5 °C. Selected numbers of vials from each type were then exposed to −25 °C for 24 h periods. All samples were evaluated for their structure using scanning electron microscopy, X-ray analysis of the elements and precipitation time. Scanning electron microscopy of vaccines affected by freezing showed either smooth or rough surfaced conglomerates associated with phosphate content of the precipitate. These vaccines precipitated 2–15 times faster compared to non-frozen samples. Non-frozen samples showed uniform flocculent structure either dense or dispersed. X-ray analysis of precipitates in frozen samples confirmed that the precipitate is mainly aluminium clutters. Scanning electron microscopy confirmed that the lattice structure of bonds between adsorbent and the antigen is broken and aluminium forms conglomerates that grow in size and weight. The precipitation time of vaccines affected by freezing is 4.5 times faster on average compared to non-frozen samples. These facts form the basis of the "shake test".

Adjustment of the activity of adsorbents for chromatographic use (e.g. Al2O3 or CaHPO4 by the controlled take-up of water) can be done in a reproducible and accurate manner with the aid of the “shake-test”. It consists in shaking a weighed sample (2 g) of the adsorbent with a measured volume (10 ml) of the elution solvent in which the substance to be eluted (e.g. 1000 I.U. of vitamin-A) has been dissolved. The activity is suitable if about 50% is adsorbed. The following operations can be performed by means of the shake test. (1) determination of the activity of adsorbents; (2) adjustment of the activity of an adsorbent; (3) replacement of an adsorbent by another of the same activity; (4) finding the correct composition of the elution solvent; (5) replacement of one solvent by another of equal eluting power. The shake test has been developed for a 10 cm column containing 10 g of Al2O3; 40 % adsorption is satisfactory for rapid elution. If slower elution is wanted, or if thinner columns (containing less adsorbent) are employed, the percentage adsorption must be larger than 40%, up to 60%. The shake test is a purely practical test; no theoretical significance can be attached to it.

OBJECTIVE: To determine the validity of the shake test for detecting freeze damage in aluminium-based, adsorbed, freeze-sensitive vaccines. METHODS: A double-blind crossover design was used to compare the performance of the shake test conducted by trained health-care workers (HCWs) with that of phase contrast microscopy as a "gold standard". A total of 475 vials of 8 different types of World Health Organization prequalified freeze-sensitive vaccines from 10 different manufacturers were used. Vaccines were kept at 5 °C. Selected numbers of vials from each type were then exposed to "25 °C and "2 °C for 24-hour periods. FINDINGS: There was complete concordance between HCWs and phase-contrast microscopy in identifying freeze-damaged vials and non-frozen samples. Non-frozen samples showed a fine-grain structure under phase contrast microscopy, but freeze-damaged samples showed large conglomerates of massed precipitates with amorphous, crystalline, solid and needle-like structures. Particles in the non-frozen samples measured from 1 μm (vaccines against diphtheria-tetanus-pertussis; Haemophilus influenzae type b; hepatitis B; diphtheria-tetanus-pertussis-hepatitis B) to 20 μm (diphtheria and tetanus vaccines, alone or in combination). By contrast, aggregates in the freeze-damaged samples measured up to 700 μm (diphtheria-tetanus-pertussis) and 350 μm on average. CONCLUSION: The shake test had 100% sensitivity, 100% specificity and 100% positive predictive value in this study, which confirms its validity for detecting freeze damage to aluminium-based freeze-sensitive vaccines.

Rudin, NIBEM, lacing index, cylinder pour, and shake foam quality tests were comprehensively compared to evaluate their utility and responsiveness to beer components that are thought to influence foam quality. Each of the tests responded differently to beer characteristics that influence beer foam quality. The Rudin and shake tests responded positively to the level and content of foam-promoting proteins (i.e., protein Z4) and also to the level of isomerized hop α-acids in beer. However, the shake test did not differentiate between isomerized and hydrogenated hop α-acids, whereas the Rudin test did. The lacing index responded positively to isomerized hop α-acids, hydrogenated in particular, but possibly negatively to alcohol. Hydrogenation of hop α-acids and protein Z4 increased foam stability as measured by the cylinder pour test, whereas alcohol, higher pH, and CO 2 level tended to reduce foam stability. A positive association with the level of isomerized hop acids was not observed; however, further investigation is required to clarify this. Finally, the NIBEM test results were influenced positively by the level of isomerized hop acids and protein Z4, while they were negatively correlated with viscosity and final gravity. Hop α-acid hydrogenation substantially improved NIBEM foam stability compared with isomerized hop α-acids. The NIBEM test was correlated positively with the Rudin, cylinder pour, lacing index, and shake (foam quality generated) tests. These comparisons and observations suggest how these foam quality evaluation tests may be best used for quality control/assurance and beverage development.

Clinical relevance:Among the factors that significantly influence the depth of cure of resin composite restorations—the distance between the tip of the light source and the restorative material—as well as the geometry of the tip, are crucial parameters. Increasing the ratio between the entry and exit diameter of the tip will result in an improvement in the depth of cure for lower distances between the tip of the light source and the restorative material, while decreasing the ratio of the depth of cure, which will be higher for greater distances.Summary:This study investigated the influence of the light guide shape on the polymerization efficacy of a light-activated resin-based composite cured with LED units as a function of the distance between the tip and the restoration.Two different LED units, each with different light guides and shapes, were used. Their ability to cure a single restorative material was investigated. The efficacy of the light-curing system was evaluated by measuring the depth of cure using the Acetone Shake test.Considering the ratio (R) between the entry diameter and the exit diameter of the light guide, the tips with a higher R-value proved to be more efficient if the tip and composite distance (D) was less than 5 mm, while for D>5 mm, the tips with a lower R-value showed better results.The tip geometry of the tested light guide had a significant influence on the depth of cure of the tested resin composites. Therefore, depending on the distance, the more suitable light guide should be selected, based on the clinical situation. An R-value may be a better descriptor for the light guide shape than words such as "normal" or "turbo."

Industrial manufacturing of solid oral dosage forms require quality tests, such as friability, hardness, and disintegration. The United States Pharmacopeia (USP) disintegration test uses 900mL of water. However, recent studies of orally disintegrating tablets (ODTs) have shown that this volume does not accurately portray the oral environment. In our study, various tests were conducted with a more moderate amount of water that accurately resembles the oral environment. A simulated wetting test was performed to calculate the water absorption ratio. Results showed that wetting was comparable to disintegration. Although the wetting test worked for most types of ODTs, it had limitations that produced inaccurate results. This led to the use of a modified shaking water bath test. This test was found to work for all types of ODT products and was not subject to the limitations of the wetting test. The shake test could provide disintegration times rather than water permeation times; however, it could not be used to calculate the water absorption ratio. A strong correlation was observed between the standardized shake test and the USP disintegration times for the tablets. This shake test could be used during the development stages and quality tests for ODTs with relative ease.

This study was designed to test measurement error in a digital pedometer. Twenty-four Yamax MLS-2000 digital pedometers were tested using a walking test and a shake test before and after heavy use in a large study. The mean deviation from 100 steps for the walking test was 2.26 ± .80 (M ± SD) and 1.71 ± .88 on pretest and posttest, respectively. Mean deviation from 100 shakes for the shake test was 0.39 ± 0.29 and 0.60 ± 0.62 for the pretest and posttest, respectively. No pedometer exceeded 5% error (i.e., 5 steps out of 100) on any of the tests. No significant differences were found between the pretest and posttest, F(1, 46) = 1.49, p ⪈ .229, but significant differences were found between the walking and the shake tests, F(1, 46) = 109.04, p < .01. The interaction was significant, F(1, 46) = 7.76, p £ .008. This study demonstrated that very little measurement error existed in the Yamax MLS-2000 digital pedometer. Researchers can have confidence that the scores obtained using this pedometer are accurate.

Background: Immunization is the effective method of preventing childhood diseases. One of the important elements for improving the immunization is cold chain and vaccine logistics management which are the left and right hands of immunization programme. Keeping this in mind, the present study was done with the objectives a) to ascertain the status of cold chain equipment and logistics management using GOI monitoring format and b) to ascertain the awareness and practice of cold chain handlers about cold chain equipment and logistics management in Durg district of Chhattisgarh, India.Methods: A cross sectional study was conducted among randomly selected 20 cold chain points (CCPs) of Durg district using standard GOI structured questionnaires.Results: Out of 20 cold chain points (CCPs), 20% CCPs, vaccine were found in frozen state. Functional thermometer was available in 75% CCPs, out of which 65% had temperature in the recommended range. Twice daily recording of temperature was found only in 95 % CCPs. Record of power failures and defrosting was noted in temperature log books in 70% CCPs. The correct placement of ice packs inside Deep freezer was observed in only one CCPs. T-series vaccine vials were placed properly in ILR in 85% CCPs. With respect to knowledge on freeze sensitive vaccine and shake test, 74 % and 53% of cold chain handlers had correct knowledge.Conclusions: The quality of immunization programme can be increased by proper maintenance of cold chain and management of vaccine logistics at every designated cold chain points. There is need to improve the knowledge level of CCHs regarding cold chain maintenances and handling practices.

Respiratory failure secondary to pulmonary surfactant deficiency is an important cause of severe respiratory distress in term and preterm infants. The aim of this study was to evaluate the specificity and sensitivity of gastric aspirate shake test (GAST) to predict surfactant deficiency in newly born premature infants in Arash Hospital (Iran) during 2012-13.In this case-control study, the case group comprised 69 premature infants (gestational age37 weeks) who were admitted to the neonatal intensive care unit due to respiratory distress. The control group included 50 healthy infants .GAST test was done. The subjects were finally categorized as healthy or surfactant-deficient based on clinical and radiological assessments.Using statistical methods the sensitivity, specificity, and positive and negative predictive values of GAST were 60%, 75%, 15%, and 52%, respectively. There was a significant difference between respiratory distress syndrome (RDS) scores and receiving surfactant in neonates with gestational age below 34 weeks. Moreover, there were significant differences between GAST results and both radiological findings of RDS and receiving oxygen in premature infants (gestational age34 weeks). Negative GAST results were more prevalent in neonates who were born to mothers with hypothyroidism, preeclampsia, diabetes mellitus, and premature rupture of membranes. However, this difference was not significant.According to our findings, the application of GAST on gastric aspirate secretions is not a useful method to predict surfactant deficiency. Therefore, decisions for RDS management must be made based on clinical and radiological findings.

Die innovative “Canning”-Technologie von Gillet, einem der weltweit fuhrenden Abgassystemhersteller, bietet hohe technische Zuverlassigkeit bei gutem Preis-Leistungs-Verhaltnis.

In this text we introduce The Ruili wave method to measure compound groundsill resistance shake. And compare with result of static load and power touch method. Through comparing with the spot test result, The Ruili wave method to measure compound groundsill resistance shake is dependable, but also can be used to measure many points. It may give result by layering and test result is more representational.

Shake table tests are evaluating how well the unreinforced masonry structures in New York City known as row houses would withstand even a moderate earthquake.

An infant asphyxiated when a machine screw detached from a crib, the headboard separated from the crib rod, and the infant’s head stuck in the opening. The evaluation of infant cribs by inanimate standard test protocols is enhanced by live child crib shake testing. This live testing provides data for quantifying the horizontal push and pull forces that children actually apply to the sides of a crib. Comparisons are made between the live child shake test results and the inanimate test requirements contained in crib safety standards. Although the inanimate standard test protocols are inconsistent, the machine screw did not fail from normal use because the inanimate test requirements far exceed the maximum live results.Copyright © 2002 by ASME

Summary. The reliability of two rapid bedside tests of fetal lung maturity was investigated in 80 amniotic fluid samples. The results of the ‘tap’ test and those of the shake test were compared with the results of laboratory measurements of phospholipid profiles for fetal lung maturity. The tap test was found to be more reliable with a positive predictive value of 91% and a negative predictive value of 63%, whereas the shake test had a positive predictive value of 79% and a negative predictive value of 31%. The tap test was also more reliable in identifying fetuses with borderline lecithin/sphingomyelin ratios in the range 3.2–3.7:1.

Objective: The aim of the study was to determine the sensitivity, specificity and predictive value of two simple and cheap diagnostic tests of fetal pulmonary maturity (FPM) and compare them with the more complex and expensive phospholipid profile (PP), which includes the determination of phosphatidyl glycerol (PG) and the lecithin/sphingomyelin ( L S ) ratio. Methods: Samples of amniotic fluid were obtained from 70 patients between the 26th and 38th weeks of pregnancy. The PP, shake test and tap test at 2, 5 and 10 min were determined. All patients gave birth within 12 h following these tests and none received corticoids during this period. The neonates were observed for 72 h. The results of the tests were compared with the incidence of neonatal respiratory distress syndrome. Results: The sensitivity of the shake test was 92% for FPM, as was the sensitivity of PP, while for the tap test at 2, 5 and 10 min it was between 96 and 100%. In terms of specificity, the 5- and 10-min tap test diagnoses were 100% correct for immaturity while all other tests were 60–78% correct. The predictive value for maturity was 100% for the tap test (5 and 10 min), 67% for the 2-min tap test, 64% for PG, 60% for L/S and 56% for the shake test. Conclusion: The tap test is a good alternative to other diagnostic methods of FPM. Its use at the bedside, its rapidity and low cost enhance its value.

945 Gastric Aspirate Shake Test for Predicting of Surfactant Therapy in Premature Neonates with Hyaline Membrane Disease

A short history is traced of the work done at Sikorsky Aircraft under the NASA/industry DAMVIBS program. This includes both work directly funded by the program as well as work which was internally funded but which received its initial impetus from DAMVIBS. The development of a finite element model of the UH-60A airframe having a marked improvement in vibration-predicting ability is described. A new program, PAREDYM, developed at Sikorsky, which automatically adjusts an FEM so that its modal characteristics match test values, is described, as well as the part this program played in the improvement of the UH-60A model. Effects of the bungee suspension system on the shake test data used for model verification are described. The impetus given by the modeling improvement, as well as the recent availability of PAREDYM, has brought for the first time the introduction of low-vibration design into the design cycle at Sikorsky.

Neonatal pulmonary maturity was studied by the Clements shake test in gastric aspirate of 52 newborn infants and their results were compared with those of the same shake test performed in amniotic fluid. Visual assessment, acidity, cytology and the shake test showed marked similarities between gastric aspirate and amniotic fluid obtained immediately before delivery. No infants with a positive shake test in amniotic fluid or gastric aspirate developed RDS while 4 of 5 infants with intermediate or negative shake test results developed RDS.

Objective: The purpose of this study was to evaluate the new method called MMBT (modified microbubble rating test) for the early detection of respiratory distress syndrome in neonates in comparison with the SMR test (stable microbubble rating test) and the Shake test on the same gastric aspirates.

Summary One hundred and six samples of amniotic fluid were analyzed independently by four clinicians for surfactant content, using the shake test and the palmitic acid content of the amniotic fluid. The variation of the results in the 424 shake tests were examined and the shake tests correlated with the palmitic acid levels. A positive shake test to a dilution of 1:4 had a 100 per cent correlation with a mature palmitic acid level over 35 pg./ml., while a positive test at a dilution 1:2 gave a 5.6 per cent false positive rate. A high false negative rate was found, however, and estimates of the chance of a mature surfactant level in relation to the range of shake tests results are given. Eleven patients had low palmitic acid levels in the amniotic fluid prior to delivery and three of the infants developed the respiratory distress syndrome.

Phosphatidylglycerol and the lecithin/sphingomyelin (L/S) ratio were determined, and the shake test was performed, as indicators of fetal lung maturity, in more than 600 patients. A clinical review of the outcome was made in all patients who underwent delivery within 2 days after collection of amniotic fluid. Correlation was made between phosphatidylglycerol, shake test, and L/S ratio results. L/S ratio had a false positive rate of 5%, and a false negative rate of 58.1%. The shake test had a false positive rate of 1.1%, and a false negative rate of 63.5%. Phosphatidylglycerol determination had a false positive rate of 1.8%, and a false negative rate of 26.9%. Phosphatidylglycerol determination is an accurate predictor of fetal lung maturity, and predicts lung immaturity more correctly than do the L/S ratio and shake test.

Summary A new rapid test of fetal lung maturity (the AmnioStat-FLM) was compared with two currently available rapid tests and with 2-dimensional thin-layer chromatography (2-d TLC). Forty-nine specimens of liquor obtained within 72 h of delivery were assessed, 27 of which were contaminated with blood or meconium. The AmnioStat-FLM compared well with spectrophotometry, the shake test and with 2-d TLC. Only the Amniostat-FLM and the 2-d TLC were reliable in the presence of contamination. The results suggest that the AmnioStat-FLM is a reliable, rapid test and unaffected by the presence of contamination.

Results of the "Amniostat-FLM" assay, a rapid semiquantitative test for phosphatidylglycerol, were compared with determinations of the lecithin/sphingomyelin (L/S) ratio, with phosphatidylglycerol measured by two-dimensional thin-layer chromatography, and with results of the "shake test" for 94 specimens of amniotic fluid. Correlation between results with the Amniostat and the other tests was excellent. All four tests are very accurate when predicting lung maturity. The predictive value of a negative test, i.e., that hyaline membrane disease would not occur, was between 92 and 100%. However, the accuracy of predicted lung immaturity is poor. For all four tests, predictions of lung immaturity were incorrect in more than 50% of the cases. Of the 49 infants born within 72 h of testing, none developed hyaline membrane disease when phosphatidylglycerol was detectable by either method or when the shake test indicated fetal lung maturity, but three infants with L/S ratio greater than 2/1 did develop the disease. The Amniostat provides a rapid screening method for detecting phosphatidylglycerol in amniotic fluid, which could well replace the thin-layer chromatographic method for measuring phosphatidylglycerol in the panel of diagnostic tests for fetal lung maturity.

A simplified, single-step shake test has been performed on gastric aspirate samples from 85 preterm infants and a control group of 214 term infants. Respiratory symptoms were seen in 25 of 30 preterm infants with a negative or intermediate test, but in only 2 of 55 infants with a positive test (P less than 0-001). No infant with a positive test developed respiratory distress syndrome (RDS) while RDS developed in 66% of those preterm infants with a negative test. False-negative results were not seen in the preterm group. The gastric aspirate shake test had better sensitivity and selectivity in prediction of clinical outcome than did the amniotic fluid lecithin/sphingomyelin ratio in 37 preterm infants in whom both results were available. Serial shake tests were performed on samples from a number of infants with RDS and the results were seen to change in parallel with clinical recovery. This and other observations suggest that the result of the gastric aspirate shake test depends more upon direct swallowing of fetal lung liquid than on swallowing of amniotic fluid.

Summary One hundred and ninety samples of amniotic fluid were analyzed for their surfactant content by measuring the lecithin-sphingomyelin ratio and performing the simple “shake test”. The value of these tests in predicting the respiratory performance of the baby at delivery is discussed and the limitations of the tests is evaluated. It was concluded that the shake test is valuable only as a screening procedure for deter-mining fetal lung maturity.