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The overall objectives of this thesis were (1) to evaluate a filter system to harvest plasma for identification of failure of passive transfer in newborn calves, (2) to evaluate 2 different treatment procedures after calving to improve harvesting of high-quantity and high-quality colostrum, and (3) to evaluate different analytical methods to assess failure of passive transfer in neonatal calves. To validate a filter system to harvest plasma for the assessment of failure of passive transfer (FPT) in neonatal calves, venous blood samples (serum and plasma) were withdrawn from 227 Holstein Friesian calves aged 1 to 7 d. Serum IgG concentrations were determined using a sandwich enzyme-linked immunosorbent assay (ELISA) (gold standard), and failure of passive transfer was defined as IgG concentrations below 10 mg/mL. Serum was obtained through centrifugation, and plasma was extracted either through centrifugation or a disposable filter system (2-Drop-Filter, Pharmadoc, L��beck, Germany). To assess the total proteins (TP) and total solids (TS) in serum and plasma, a handheld optical refractometer (Euromex Holland, Arnhem, the Netherlands) and 2 digital Brix refractometers (device 1: HI 96801 digital refractometer, Hanna Instruments, Woonsocket, RI; device 2: Misco PA201, Misco, Solon, OH) were used. The optimal threshold for each device and each medium, i.e centrifuged serum, centrifuged plasma, and filtered plasma, was calculated using the receiver operating characteristic (ROC) curve analyses. The prevalence of failure of passive transfer in neonatal calves was 30% (67/227). The optimal threshold for the handheld optical refractometer using serum was 5.6 g/dL [sensitivity (Se) 70.1%; specificity (Sp) 80.0%; area under the curve (AUC) 0.85]. For centrifuged plasma, the optimal threshold was higher at 6.3 g/dL (Se 82.1%; Sp 68.1%; AUC 0.84), and for filtered plasma, the threshold was 6.0 g/dL (Se 56.7%; Sp 90.0%; AUC 0.80). The digital Brix refractometer (device 1: HI 96801) had the optimal threshold at 8.9% Brix using serum (Se 82.1%; Sp 63.8%; AUC 0.81), and at 9.4% Brix (Se 76.1%; Sp 73.7%; AUC 0.80) using centrifuged plasma, respectively. The device 2 (Misco PA201) determined the optimal threshold at 8.7% Brix (Se 74.6%; Sp 76.2%; AUC 0.83), 9.5% Brix (Se 80.6%; Sp 70.6%; AUC 0.83), and 9.2% Brix (Se 58.2%; Sp 87.5%; AUC 0.80) using serum, centrifuged plasma, and filtered plasma, respectively. All the three devices with the different media had comparable test characteristics to assess calves with FPT, based on the AUC determined with ROC curve analyses. Plasma samples (centrifuged and filtered plasma) revealed higher optimal thresholds to assess FPT compared with serum. Furthermore, the three different devices had comparable AUC irrespective of the used medium (centrifuged serum, centrifuged plasma, or filtered plasma). The results demonstrate that a filter system is suitable as a point-of-care analysis for FPT assessment, but further research is necessary. The aim of the second study was to evaluate two different treatment procedures at first milking after calving to increase colostrum quantity and to improve colostrum quality in dairy cows. We assumed that exogenous treatment with oxytocin or the presence of the calf at harvesting the first colostrum would lead to higher colostrum quantity and higher IgG concentrations. For the study, a total of 567 dairy cows were enrolled. For the final analyses, only 521 animals were considered and 46 dairy cows were excluded due to several reasons, such as lameness, bloody or mastitic colostrum, gestation length of less than 265 d, twin births and missing data. Three groups were built in which the cows were randomly assigned on a daily basis: (1) control group (CON; n = 177), (2) application of 20 IU of oxytocin i.m. (OXY; n = 163), and (3) presence of the calf (CA; n = 181) before and during milking. The milking of the first colostrum took place in a separate milking parlor. Dairy cows in the control and oxytocin group had no contact with their calves after calving. Three minutes before manual stimulation, the cows in the oxytocin group were injected with 20 IU of oxytocin i.m. into the neck region. Cows in the CA group got their calf presented three minutes before milking, whereby the calf was placed into a calf cart and located in front of the cow. Colostrum quantity (kg) was recorded and colostrum quality was determined by Brix refractometry and ELISA. To evaluate the data a generalized linear mixed model (GENLINMIXED) was constructed using SPSS (SPSS Inc., IBM, Ehningen, Germany). The mean colostrum quantity was 4.17 �� 0.30 kg (means �� SE). The treatment procedures and the harvesting time after calving did not affect colostrum quantity, but parity, calf birth weight, and calving time had an influence on colostrum quantity. The lowest quantity of colostrum had cows in second parity (3.74 �� 0.37 kg). Whereas cows in parity 1 (4.75 �� 0.34 kg) and cows in parity 3 or greater (4.75 �� 0.38 kg) had higher colostrum quantities. Further, cows calving at night (22:00 until 06:00 h; 4.93 �� 0.37 kg) had the highest quantity of colostrum. Cows calving in the morning (06:00 until 14:00 h; 4.17 �� 0.38 kg) or afternoon (14:00 until 22:00 h; 4.14 �� 0.34 kg) had a reduced amount of colostrum. Forty-eight percent of the colostrum samples assessed by ELISA contained ��� 50 mg IgG/mL (54.6 �� 2.80 mg IgG/mL). The treatment procedures had an effect on colostrum quality, as well as colostrum quantity, parity, calving time, harvesting time after calving, and the calving day during the week. The treatment procedures achieved on mean higher IgG concentrations in colostrum (OXY: 57.0 mg IgG/mL; CA: 56.0 mg IgG/mL) compared with the control group (50.7 mg IgG/mL). High colostrum quantity and a longer time lag between calving and milking decreased the colostrum quality. Cows in parity 3 or greater (64.6 �� 2.59 mg IgG/mL) had higher IgG concentrations compared with cows in parity 1 (48.5 �� 2.86 mg IgG/mL) and cows in parity 2 (50.7 �� 2.89 mg IgG/ mL). Calving at night resulted in greater IgG concentrations (60.4 �� 2.92 mg IgG/mL) compared to calving at the morning or afternoon time (51.9 �� 2.98 and 51.3 �� 2.71 mg IgG/mL). Calving on Sundays increased the colostrum quality (61.4 �� 3.70 mg IgG/mL). The treatment procedures and the harvesting time after calving had no effect on colostrum quality assessed by Brix refractometry. Nevertheless, a negative association was observed between colostrum quantity and quality as with ELISA testing. Cows in parity 3 or greater showed higher Brix readings (27.7 �� 0.26% Brix) compared with cows in parity 1 (25.3 �� 0.30% Brix) and cows in parity 2 (25.0 �� 0.32% Brix). The purpose of the third study was to evaluate different analytical methods [i.e., ELISA, capillary electrophoresis (CE), refractometry] and three different media (i.e., centrifuged serum, centrifuged plasma, filtered plasma) to assess FPT in neonatal calves. As gold standard, radial immunodiffusion (RID) was chosen, and as before, FPT was defined by serum IgG concentrations < 10 mg/mL. Blood samples were collected from Holstein Friesian calves (n = 216) aged 1 to 7 days, from two commercial dairy herds in Northeast Germany. Serum was gained through centrifugation, and plasma extraction was performed either through a filter system or through centrifugation, as in the first study. For plasma filtration a disposable plasma filter was used (2-Drop-Filter, Pharmadoc, L��beck, Germany). The laboratory methods, RID, ELISA, and CE, determined the IgG concentration in serum samples. For refractometry, two refractometers were used, a handheld optical refractometer (RF.5612 Handheld refractometer, Euromex Holland, Arnhem, Netherlands), assessing the TP concentration in all three media, and a digital Brix refractometer (Misco PA201, Misco, Solon, OH), assessing the TS, respectively. The RID analysis showed a prevalence of FPT of 27% (59/216) and 73% (157/216) with successful passive transfer. The Pearson correlation coefficient between RID and CE in serum was r = 0.97, and between RID and ELISA, it was r = 0.90, respectively. In addition, a high correlation between CE and ELISA could be identified (r = 0.89). Refractometry results were highly correlated with RID using either centrifuged serum, centrifuged plasma, or filtered plasma (Brix refractometer: r = 0.84; r = 0.80; r = 0.78; handheld optical refractometer: r = 0.83; r = 0.81; r = 0.80). The test characteristics to identify calves with FPT (optimal thresholds, Se, Sp, positive predictive value [PPV], negative predictive value [NPV], and AUC) for all methods and the three different media were determined by ROC curve analyses by using RID as the reference value. In summary, all four different analytical methods were suitable to assess FPT (ELISA, CE, and two refractometry methods). The test accuracy within the direct laboratory methods and within the indirect on-farm devices was very good, as the 95% CI for AUC overlapped, regardless of the three different media (centrifuged serum and plasma, or filtered plasma). However, different cutoff values for each analytical method must be considered, in particular if different media were used. The results demonstrate again, as in the first study, that optimal thresholds using plasma were higher compared with serum. In conclusion, all methods can be used for the assessment of FPT, and serum and plasma samples can be used interchangeably if the different cutoff values are taken into consideration. Overall, this thesis shows that (1) a disposable plasma filter system is appropriate as a point-of-care system for FPT analysis, but further research is required, (2) exogenous oxytocin and the presence of the calf improve the IgG concentration in colostrum at the first milking, but do not have an influence on colostrum quantity, and (3) different analytical methods are suitable to assess FPT if different cutoff values are taken into account. These results have the potential to improve colostrum management and calf health on dairy farms., Die Ziele dieser Arbeit waren (1) ein Filtersystem zur Gewinnung von Plasma zu evaluieren, um eine fehlerhafte passive Immunisierung von neugeborenen K��lbern bedingt durch mangelhafte Kolostrum-Versorgung zu beurteilen. Des Weiteren (2) zwei verschiedene Behandlungsverfahren nach dem Abkalben zu untersuchen, um die Kolostrum-Menge und Kolostrum-Qualit��t zu verbessern. Sowie (3) verschiedene Analysemethoden zur Beurteilung der fehlerhaften passiven Immunisierung durch mangelhafte Kolostrum-Versorgung von neugeborenen K��lbern zu bewerten. Um ein Filtersystem zur Plasmagewinnung f��r die Beurteilung der fehlerhaften passiven Immunisierung bzw. Transfers (FPT) bei neugeborenen K��lbern zu validieren, wurden ven��se Blutproben untersucht. Serum- und Plasmaproben wurden von 227 K��lbern der Rasse Holstein Friesian im Alter von ein bis sieben Lebenstagen entnommen. Die IgG-Konzentration im Serum wurde als Goldstandard mittels Sandwich Enzyme-linked Immunosorbent Assay (ELISA) bestimmt. Alle K��lber mit IgG-Konzentrationen < 10 mg/mL im Serum waren von FPT betroffen. Serum wurde durch Zentrifugation gewonnen und Plasma wurde entweder durch Zentrifugation oder durch ein Einweg-Filtersystem (2-Drop-Filter, Pharmadoc, L��beck, Deutschland) extrahiert. Um das Totalprotein (TP) und die Gesamtfeststoffe (TS) im Serum und Plasma zu bestimmen, wurden ein tragbares optisches Refraktometer (Euromex Holland, Arnhem, Niederlande) und zwei digitale Brix-Refraktometer (Ger��t 1: HI 96801 digitales Refraktometer, Hanna Instruments, Woonsocket, RI; Ger��t 2: Misco PA201, Misco, Solon, OH) verwendet. Der optimale Grenzwert f��r jedes Ger��t und jedes Medium, d.h. f��r zentrifugiertes Serum, zentrifugiertes und gefiltertes Plasma, wurde anhand der ROC-Kurven-Analyse (Receiver Operating Characteristics) berechnet. Die Pr��valenz von FPT bei neugeborenen K��lbern befand sich bei 30 % (67/227). Der optimale Grenzwert f��r das optische Refraktometer betrug 5,6 g/dL im Serum (Sensitivit��t [Se] 70,1 %; Spezifit��t [Sp] 80,0 %; Fl��che unter der Kurve [AUC] 0,85). F��r zentrifugiertes Plasma lag der optimale Grenzwert h��her, bei 6,3 g/dL (Se 82,1 %; Sp 68,1 %; AUC 0,84) und f��r gefiltertes Plasma lag er bei 6,0 g/dL (Se 56,7 %; Sp 90,0 %; AUC 0,80). Das digitale Brix-Refraktometer (Ger��t 1: HI 96801) zeigte den optimalen Grenzwert von 8,9 % Brix im Serum (Se 82,1 %; Sp 63,8 %; AUC 0,81) und 9,4 % Brix (Se 76,1 %; Sp 73,7 %; AUC 0,80) im zentrifugierten Plasma an. Das zweite Ger��t (Misco PA201) hatte den optimalen Grenzwert von 8,7 % Brix im Serum (Se 74,6 %; Sp 76,2 %; AUC 0,83), 9,5 % Brix im zentrifugierten Plasma (Se 80,6 %; Sp 70,6 %; AUC 0,83) und 9,2 % Brix im gefilterten Plasma (Se 58,2 %; Sp 87,5 %; AUC 0,80). Alle drei Ger��te mit den verschiedenen Medien hatten vergleichbare Testeigenschaften, um K��lber mit FPT zu beurteilen, basierend auf der AUC, die mit der ROC-Kurven-Analyse bestimmt wurde. Plasmaproben (zentrifugiertes und gefiltertes Plasma) hatten h��here optimale Grenzwerte zur Beurteilung von FPT im Vergleich zu Serumproben. Dar��ber hinaus zeigten die drei verschiedenen Ger��te unabh��ngig vom verwendeten Medium (zentrifugiertes Serum, zentrifugiertes oder gefiltertes Plasma) vergleichbare AUC. Aus den Ergebnissen l��sst sich schlie��en, dass ein Filtersystem als Point-of-Care-Analyse f��r die FPT-Bewertung geeignet ist, aber weitere Forschung dazu notwendig ist. Das Ziel der zweiten Studie war es, zwei verschiedene Behandlungsverfahren beim ersten Melken nach dem Kalben zu bewerten, um die Kolostrum-Menge und die Kolostrum-Qualit��t bei Milchk��hen zu verbessern. Unsere Hypothese lautete, dass eine Behandlung mit Oxytocin oder das Vorhandensein des Kalbes beim ersten Melken nach der Kalbung zu einer h��heren Kolostrum-Menge und zu einer h��heren IgG-Konzentration f��hrt. In die Studie gingen insgesamt 567 Milchk��he ein. F��r die endg��ltige Auswertung wurden aber nur 521 Tiere ber��cksichtigt, da 46 Milchk��he aus verschiedenen Gr��nden ausgeschlossen wurden, z.B. Lahmheit, blutiges oder entz��ndlich ver��ndertes Kolostrum, Tr��chtigkeitsdauer unter 265 Tagen, Zwillingsgeburten und fehlende Daten. Es wurden drei Gruppen gebildet, denen die K��he t��glich zuf��llig zugeordnet wurden: (1) Kontrollgruppe (CON; n = 177), (2) Anwendung von 20 IE Oxytocin i.m. (OXY; n = 163) und (3) Vorhandensein des Kalbes (CA; n = 181) vor und w��hrend des Melkens. Das Melken des ersten Kolostrums erfolgte in einem separaten Melkstand. Milchk��he in der Kontroll- und Oxytocingruppe hatten nach dem Kalben keinen Kontakt zu ihren K��lbern. Drei Minuten vor der manuellen Stimulation wurde den K��hen der Oxytocingruppe 20 IE Oxytocin i.m. in die Halsregion injiziert. Den K��hen der CA-Gruppe wurde drei Minuten vor dem Melken ihr Kalb pr��sentiert, wobei das Kalb in eine Transportkarre f��r K��lber gelegt und vor der Kuh platziert wurde. Die Kolostrum-Menge wurde in Kilogramm erfasst und die Kolostrum-Qualit��t wurde mittels Brix-Refraktometrie und ELISA bestimmt. Zur Auswertung der Daten wurde mit SPSS (SPSS Inc., IBM, Ehningen, Deutschland) ein generalisiertes lineares gemischtes Modell (GENLINMIXED) erstellt. Die mittlere Kolostrum-Menge betrug 4,17 �� 0,30 kg (Mittelwert �� Standardfehler). Die Behandlungsverfahren und die Zeit des ersten Melkens nach dem Kalben hatten keinen Einfluss auf die Kolostrum-Menge, aber die Laktationsanzahl, das Geburtsgewicht des Kalbes und die Kalbezeit hatten einen Einfluss auf die Kolostrum-Menge. Die geringste Menge hatten K��he in zweiter Laktation (3,74 �� 0,37 kg). W��hrend Erstkalbinnen (4,75 �� 0,34 kg) und K��he in Laktation 3 oder h��her (4,75 �� 0,38 kg) h��here Kolostrum-Mengen aufwiesen. Weiterhin hatten K��he, die nachts kalbten (22:00 bis 06:00 Uhr; 4,93 �� 0,37 kg), die h��chste Kolostrum-Menge. K��he, die morgens (06:00 bis 14:00 Uhr; 4,17 �� 0,38 kg) oder nachmittags (14:00 bis 22:00 Uhr; 4,14 �� 0,34 kg) kalbten, hatten eine geringere Kolostrum-Menge. Achtundvierzig Prozent der mit ELISA untersuchten Kolostrumproben enthielten ��� 50 mg IgG/mL (54,6 �� 2,80 mg IgG/mL). Die Qualit��t des Kolostrums wurde durch die Behandlungsverfahren sowie durch die Kolostrum-Menge, die Laktationsanzahl, die Kalbezeit, die Zeit des ersten Melkens nach dem Kalben und den Wochentag, an dem die Abkalbung stattfand, beeinflusst. Die Behandlungsverfahren f��hrten zu durchschnittlich h��heren IgG-Konzentrationen im Kolostrum (OXY: 57,0 mg IgG/mL; CA: 56,0 mg IgG/mL) im Vergleich zur Kontrollgruppe (50,7 mg IgG/mL). Eine hohe Kolostrum-Menge und eine l��ngere Zeitverz��gerung zwischen Kalben und Melken verminderten die Kolostrum-Qualit��t. K��he in Laktation 3 oder h��her (64,6 �� 2,59 mg IgG/mL) hatten eine h��here IgG-Konzentration als Erstkalbinnen (48,5 �� 2,86 mg IgG/mL) und K��he in Laktation 2 (50,7 �� 2,89 mg IgG/mL). Das Kalben in der Nacht f��hrte zu h��heren IgG-Konzentrationen (60,4 �� 2,92 mg IgG/mL) im Vergleich zum Kalben am Morgen oder Nachmittag (51,9 �� 2,98 und 51,3 �� 2,71 mg IgG/mL). Das Kalben an Sonntagen erh��hte die Kolostrum-Qualit��t (61,4 �� 3,70 mg IgG/mL). Die Behandlungsverfahren und die Zeit des ersten Melkens nach dem Kalben hatten keinen Einfluss auf die Kolostrum-Qualit��t, die durch Brix-Refraktometrie beurteilt wurde. Dennoch wurde wie bei der ELISA-Untersuchung ein negativer Zusammenhang zwischen Kolostrum-Menge und Qualit��t festgestellt. K��he in Laktation 3 oder h��her zeigten h��here Brixwerte (27,7 �� 0,26 % Brix) im Vergleich zu Erstkalbinnen (25,3 �� 0,30 % Brix) und K��hen in Laktation 2 (25,0 �� 0,32 % Brix). Das Ziel der dritten Studie war es, verschiedene Analysemethoden (d.h. ELISA, Kapillarelektrophorese [CE], Refraktometrie) und drei verschiedene Medien (d.h. zentrifugiertes Serum, zentrifugiertes Plasma, gefiltertes Plasma) zur Beurteilung von FPT bei neugeborenen K��lbern zu evaluieren. Als Goldstandard wurde die radiale Immundiffusion (RID) gew��hlt und FPT wurde, wie schon erw��hnt, mit IgG-Konzentrationen < 10 mg/mL im Serum definiert. Blutproben wurden von K��lbern der Rasse Holstein Friesian (n = 216) im Alter von ein bis sieben Lebenstagen aus zwei kommerziellen Milchviehbetrieben in Nordostdeutschland entnommen. Das Serum wurde durch Zentrifugation gewonnen und die Plasmaextraktion wurde, wie bereits in der ersten Studie, entweder durch ein Filtersystem oder durch Zentrifugation durchgef��hrt. F��r die Plasmafiltration wurde ein Einweg-Plasmafilter verwendet (2-Drop-Filter, Pharmadoc, L��beck, Deutschland). Die Labormethoden, RID, ELISA und CE, bestimmten die IgG-Konzentration in den Serumproben. F��r die Refraktometrie wurden zwei Refraktometer verwendet, ein optisches Refraktometer (RF.5612 Handrefraktometer, Euromex Holland, Arnheim, Niederlande) zur Beurteilung der TP-Konzentration in allen drei Medien und ein digitales Brix-Refraktometer (Misco PA201, Misco, Solon, OH) zur Beurteilung der TS. Die RID-Analyse ergab eine FPT-Pr��valenz von 27 % (59/216). Der Pearson-Korrelationskoeffizient zwischen RID und CE lag bei r = 0,97 im Serum; zwischen RID und ELISA lag er bei r = 0,90. Dar��ber hinaus konnte eine hohe Korrelation zwischen CE und ELISA festgestellt werden (r = 0,89). Die Ergebnisse der Refraktometrie korrelierten hochgradig mit den RID-Ergebnissen im zentrifugierten Serum, zentrifugierten Plasma und gefilterten Plasma (Brix-Refraktometer: r = 0,84; r = 0,80; r = 0,78; optisches Refraktometer: r = 0,83; r = 0,81; r = 0,80). Die Testeigenschaften (optimale Grenzwerte, Se, Sp, positiver pr��diktiver Wert [PPV], negativer pr��diktiver Wert [NPV] und AUC) zur Beurteilung von K��lbern mit FPT f��r alle Verfahren und alle drei verschiedenen Medien wurden durch ROC-Kurven Analyse unter Verwendung des RID als Referenzwert bestimmt. Zusammenfassend sind alle vier verschiedenen Analysemethoden zur Beurteilung von FPT (ELISA, CE und zwei Methoden der Refraktometrie) geeignet. Die Testgenauigkeit innerhalb der direkten Labormethoden und innerhalb der indirekten On-Farm-Ger��te war sehr gut, da sich die 95 % CI f��r AUC ��berlappten, unabh��ngig von den drei verschiedenen Medien (zentrifugiertes Serum und Plasma sowie gefiltertes Plasma). Allerdings m��ssen f��r jede Analysemethode unterschiedliche Grenzwerte ber��cksichtigt werden, insbesondere, wenn unterschiedliche Medien verwendet werden. Die Ergebnisse zeigten erneut, wie in der ersten Studie, dass die optimalen Grenzwerte f��r Plasma im Vergleich zu Serum h��her lagen. Folglich k��nnen alle Methoden zur Beurteilung von FPT genutzt sowie Serum- und Plasmaproben eingesetzt werden, wenn man die unterschiedlichen Grenzwerte ber��cksichtigt. Insgesamt zeigt diese Arbeit, dass (1) ein Einweg-Plasma-Filtersystem als Point-of-Care-System f��r die FPT-Analyse geeignet ist, aber weitere Forschungsarbeit erforderlich ist, (2) exogenes Oxytocin und das Vorhandensein des Kalbes die IgG-Konzentration im Kolostrum beim ersten Melken verbessern, aber keinen Einfluss auf die Kolostrum-Menge haben, und (3) verschiedene Analysemethoden zur Beurteilung von FPT geeignet sind, wenn unterschiedliche Grenzwerte ber��cksichtigt werden. Diese Ergebnisse haben das Potenzial, das Kolostrum-Management und die Gesundheit der K��lber in Milchviehbetrieben zu verbessern.

A sufficient supply of colostral antibodies within the first hours of life is crucial for the development and the health status in young calves. It is rational to examine the immunoglobulin uptake of single animals, but particularly on a herd basis, during herd controls and consultations. This enables economical calf rearing in accordance with animal welfare. Because of the costly, laboratory-dependent and in part time-consuming direct measurement of the absorbed immunoglobulins using radial immunodiffusion (RID) or ELISA, multiple studies attempted to develop indirect methods, which would be affordable and operational in the field. These aim to draw an inference for the absorbed quantity of colostral antibodies based on other correlated parameters. Multiple validations showed in part significant differences between various methods concerning specificity and sensitivity in comparison to the direct methods. In addition to RID and ELISA, this article presents the measurement of the γ-glutamyltransferase (GGT) activity, the determination of the total serum protein concentration using refractometry and the zinc sulphate turbidity test, and describes the advantages and disadvantages of their application. Refractory measurement and determination of the GGT activity represent a valuable alternative to a laboratory-dependent immunoglobulin G measurement. Nevertheless, there is no ideal rapid test method, such that several influencing factors have to be considered.Eine ausreichende Versorgung mit kolostralen Antikörpern innerhalb der ersten Lebensstunden ist für die Entwicklung und den Gesundheitsstatus junger Kälber entscheidend. Es ist sinnvoll, im Rahmen der Bestandskontrolle und -beratung die Immunglobulinaufnahme beim Einzeltier, insbesondere aber auf Herdenebene zu überprüfen, um eine tierschutzgerechte und wirtschaftliche Kälberaufzucht zu ermöglichen. Aufgrund der aufwendigen laborgebundenen und zum Teil zeitintensiven direkten Messung der aufgenommenen Immunglobuline mittels radialer Immundiffusion (RID) oder ELISA wurde in zahlreichen Studien versucht, indirekte Methoden zu entwickeln, die vor allem kostengünstig und vor Ort verfügbar sein sollen. Diese versuchen, durch korrelierte Messgrößen einen Rückschluss auf die aufgenommene Menge kolostraler Antikörper zu ermöglichen. In zahlreichen Überprüfungen zeigten sich bei den einzelnen Methoden allerdings zum Teil erhebliche Differenzen hinsichtlich Spezifität und Sensitivität im Vergleich mit den direkten Nachweisverfahren. In diesem Artikel werden neben RID und ELISA die Aktivitätsmessung der γ-Glutamyltransferase (GGT), die Bestimmung der Gesamtproteinkonzentration im Serum mittels Refraktometrie sowie des Zinksulfattrübungstests vorgestellt und ihre Vor- und Nachteile in der Anwendung dargelegt. Insbesondere die Refraktometrie und eingeschränkt die Messung der GGT-Aktivität stellen für den Praktiker eine Alternative zur laborgebundenen IgG-Messung dar. Trotz alledem existiert keine ideale Schnellmessmethode, sodass bei den jeweiligen Verfahren Störfaktoren beachtet werden müssen.

In the last 20 years, the role of ultrashort pulsed lasers in ophthalmology has become increasingly important. However, it is still impossible to guide ultra-short laser pulses with standard glass fibres. The highly energetic femtosecond pulses would destroy the fibre material, and non-linear dispersion effects would significantly change beam parameters. In contrast, photonic crystal fibres mainly guide the laser pulses in air, so that absorption and dispersive pulse broadening have essentially no effect. This article compares classical beam guidance with mirrors, lenses and prisms with photonic crystal fibres and describes the underlying concepts and the current state of technology. A classical mirror arm possesses more variable optical properties, while the HCF (Hollow-Core Photonic Crystal Fibre) must be matched in terms of the laser energy and the laser spectrum. In contrast, the HCF has more advantages in respect of handling, system integration and costs. For applications based on photodisruptive laser-tissue interaction, the relatively low damage threshold of photonic crystal fibres compared to classic beam guiding systems is unacceptable. If, however, pulsed laser radiation has a sufficiently low peak intensity, e.g. as used for plasma-induced ablation, photonic crystal fibres can definitely be considered as an alternative solution to classic beam guidance.

Additive manufacturing and 3D printing create new paths for the design and manufacturing of implants. Technologies with high resolution are required for the development of microstructured eye implants. In the present study, we demonstrate how these technologies can be used during the design development and manufacturing of a multifocal diffractive aspheric intraocular lens.Multiphoton polymerisation (MPP) is used to manufacture a diffractive relief with resolution in the sub-micrometer range. The relief is applied to the moulded body of a refractive lens, forming a trifocal lens. Propagation of light behind the lens is visualised in water with fluorescein.Multifocal lenses were successfully manufactured with this approach. The optical design with three foci is confirmed by the light propagation images. The images even clearly demonstrate the impact of the refractive and diffractive elements and may provide information on artefacts and aberrations.Multiphoton polymerisation is an interesting tool for the flexible manufacturing of complex multifocal lenses. With future technological progress in 3D printing with MPP, this is a promising method for on-demand manufacturing of patient individual intraocular lenses.

The utilisation of the diffractive properties of Fresnel zone plates offers the possibility of intraocular lens designs with multiple foci. Such intraocular lenses can be manufactured by two-photon polymerisation (2PP). This paper explains the underlying concept and shows the principles for visualisation of the focus properties of such implants.

The choice of a suitable intraocular lens (IOL) and the calculation of postoperative refractive error is one of the most intriguing challenges of modern cataract surgery. This clinical trial compared the accuracy of two laser-assisted optical biometers, the IOL-Master 500 (Carl Zeiss Meditec, Jena, Germany) and the Lenstar LS900 (Haag-Streit, Bern, Switzerland) without taking the postoperative results into consideration.Artificial lenses (Alcon Pharma) for 114 eyes of 67 patients were measured using both biometric instruments. The deviation of the presumed refractive error from the desired preoperative refractive target was calculated with different formulae (i.e. SRK/T, HofferQ, Haigis and SRKII) based on the intraoperatively chosen IOL. The differences between both instruments were compared using Student's t-test.Using the SRKII formula a mean difference between the IOL-Master and the Lenstar of 0.07 D (p = 0.002) was calculated for 95 eyes, SRK/T used on 47 eyes showed a difference of 0.04 D (p = 0.27), HofferQ measured 0.09 D (p = 0.0001) between both instruments for 88 eyes and the Haigis formula also showed a mean difference of 0.09 D (p = 0.001) based on the calculations of 106 eyes.Both instruments gave reproducible and accurate results with only a small deviation from the desired target refraction and can therefore be considered as comparable for the calculation of IOLs. Statistically significant differences in the results were found when using the SRKII, HofferQ and Haigis formulae but these were too low to have any influence on the choice of IOL to be implanted.

Breast cancer is the most common cancer and the leading cause of cancer deaths in women worldwide.Mammography is the only imaging technique approved for nationwide breast cancer screening. Digital full field mammography has improved mammographic image quality. Nevertheless, mammography has a low positive predictive value and a low sensitivity especially in mammographically dense breasts. One of the major limitations is the inherently low contrast between healthy breast parenchyma and breast cancer.Phase contrast imaging is based on the phase shift that occurs when X-rays encounter a change in refractive index between different materials.The improved soft tissue contrast makes the technology particularly promising for breast diagnostics.The studies presented here suggest that phase contrast imaging provides additional diagnostic information both using phase contrast mammography and phase contrast computed tomography (CT).This paper provides an overview of the basic principles of the phase contrast imaging and describes recent developments towards in vivo and ex vivo phase contrast imaging of the breast.

Laser in situ keratomileusis is a safe and accepted method for correcting myopia. The operational results in terms of accuracy as well as the subjective acceptance of patients for corrections to - 8 D are now considered to be promising (Seiler, Refraktive Chirurgie der Hornhaut, 2000); however, postoperative results show individual patient problems in long-term stability. It is believed that the preoperative condition of the cornea (e.g. thickness, biomechanical properties) could have an influence on postoperative problems such as myopic regression.This study included a total of 46 eyes from 25 patients. At 3 months postoperatively, 15 patients (19 eyes) showed a SEQ of -0.50 D or more. Within this group, 11 patients (15 eyes) developed a regression (regression group) within the first 3 postoperative months. The remainder of the total group did not show any regression (stability group). The subjects of this study were on average 33 ± 8 years (stability group) and 31 ± 7 years old (regression group). The corneal thickness was tested and refractive error, visual acuity (BCVA/UCVA) and intraocular pressure was measured. In addition, the corneal hysteresis (CH) and corneal resistance factor (CRF) were determined.The mean preoperative spherical equivalent refraction was -3.14 D ± 1.41 D (SE) in the stability group and - 6.47 D ± 1.40 D (p = 0.001)in the regression group. Also, the postoperative spherical equivalents were statistically significant different (p0.05). In contrast, the mean preoperative corneal thickness showed no differences in both groups (p = 0.96) (stability group 563 ± 36 µm and regression group 563 ± 28 µm).The aim of the study to detect a possible causal relationship between myopia regression after LASIK and the biomechanical properties of the cornea and corneal thickness could not be clearly identified.

The confocal Brillouin spectroscopy is an innovative measurement method that allows the non-invasive determination of the rheological properties of materials. Its application in ophthalmology can offer the possibility to determine in-vivo the deformation properties of sections of transparent biological tissue such as the cornea or eye lens with spatial resolution. This seems to be a promising approach concerning current presbyopia research. Due to the spatially resolved detection of the viscoelastic lens properties, a better understanding of the natural aging process of the lens and the influences of different lens opacities on the stiffness is expected. From the obtained spectral data the relative protein levels, the relative refractive index profile and the relative density profile within the lens tissue can be derived in addition. A measurement set-up for confocal Brillouin microscopy based on spectral analysis of spontaneous Brillouin scattering signals by using a high-resolution dispersive device is presented. First in-vitro test results on animal and human lenses are presented and evaluated concerning their rheological significance. These data are compared with known research results.

There is uncertainty in ophthalmology concerning the quality and spectral transmission of light of so-called blue filter intraocular lenses (IOL). Clinical users have noticed that such IOL's appear to have different color intensities. The discussion on medical changes by means of such IOL's is dependent on the real light transmission of these IOL's. To add some objective data we compared these IOL's by systematic transmission measurements and observed technical differences of diffraction and geometry as well as transmission differences. The result gives objective indications that differences between blue filter IOL's from different manufacturers are important and are detailed in this paper.

Dynamic light scattering (DLS) measures the oscillations of macromolecules (MM) (Brownian motion). Small MM move fast, large MM slowly. DLS allows one to measure the relaxation of the movements of these MM, together with their sizes and their hydrodynamic diffusion coefficients. By DLS not only the pathogenesis of a large number of eye diseases but also those of general diseases may be determined. The origin of this class of diseases is the condensation (agglutination) of MM. Medicaments, such as Panthetine, have been shown to be effective in animal experiments by acting on the ionic strength of disturbed MM. They may have a fair chance to be effective also in humans. Static light scattering (tyndallometry, nephelometry) (SLS) is able to determine the weight of MM, but however their shape, as DLS can.

Scanning laser polarimetry (SLP) is another technology for early glaucoma diagnosis. This technique (represented in the GDx from Carl Zeiss Meditec, Jena, Germany) is based on polarimetry and measures the retinal nerve fiber layer (RNFL) thickness. Compared with previous instruments without customized corneal compensation, the variable corneal compensation technology enables improved differentiation between glaucoma and healthy eyes. Limitations are the atypical birefringence patterns that exist in some eyes, showing false high RNFL values. The newest software uses enhanced corneal compensation (ECC) technology to avoid these atypical patterns and to improve glaucoma diagnosis. Advantages of SLP include independence from drawing a contour line and a reference plane. Follow-up using SLP is limited, but with the use of the new ECC technology, trend and event analyses are possible. Long-term studies will determine the effectiveness of this method.

The aim of this study was to simulate the effect of illuminance on retinal image quality before and after LASIK.Wavefront sensing was performed in eighteen eyes of 12 patients before and one month after uncomplicated LASIK using a Hartmann-Shack sensor. A sigmoid curve was fitted to pupillometry data obtained at 4, 0.4 and 0.04 lux. Based on the sigmoid fit, pre- and postoperative wavefront errors were simulated for different pupil diameters over a corresponding range from 10 (-2) to 10 (2) lux. Retinal image quality was described by computation of the visual Strehl ratio based on the optical transfer function (VSOTF) for a spectacle correction preoperatively and for the uncorrected eye postoperatively.At an illuminance of 1 lux the mean pupil diameter was 4.81 +/- 0.91 mm and log VSOTF dropped from -0.47 +/- 0.29 to -1.18 +/- 0.32 (p0.001) after LASIK. The steepest pupil-induced decrease of VSOTF occurred preoperatively at 0.67 +/- 0.26 lux (range 0.2 - 1.58 lux). After LASIK, L (crit) on average was 0.96 +/- 0.53 lux (p0.05; range 0.2 - 1.78).The steepest pupil-induced decrease of retinal image quality occurred in the high mesopic range, however, there was intersubject variability.

In 360 samples of colostrum and 36 samples of blood of warmblood mares, the concentration of immunoglobulin G (IgG) was evaluated in the post partal period with an ELISA and the results were compared to values obtained with 2 field methods--refractometry and colostrometry. A significant correlation (p0.0001) was determined between ELISA and colostrometry (r = +0.88) and between ELISA and refractometry (r = +0.93). So both field-methods seem suitable for evaluation of the colostral IgG-concentration in mares. Further the kinetic of the IgG concentration in colostrum, the volume of colostrum and the total amount of IgG was measured in the 12 hours post partum (p.p.) in each half udder of 36 mares of different parity. Immediately p.p. primiparous mares have a greater mean concentration of IgG (68 mg/ml) than multiparous mares (51 mg/ml). However, multiparous mares have a mean colostral volume of 1020 ml whereas, in primiparous mares, a mean volume of 527 ml was determined within the first three hours p.p. As a result of this the total amount of IgG was lower in primiparous (31.5 g) than in multiparous mares (48.5 g). A significant decrease of IgG concentration was measured in multiparous mares in the 1.5 hours following partum versus 3 hours in primiparous mares. The mean IgG concentration in the blood serum of the 36 mares immediately p.p. was 13.4 +/- 3.6 mg/ml. No significant correlation was observed between values of IgG concentration in the blood and in the colostrum of the mares.

Comparison of the central corneal refractive power before and after myopic LASIK using the Keratograph and the Pentacam. The Scheimpflug technique (Pentacam) enables the measurement of the corneal refractive power by examining the anterior and posterior corneal curvature.The corneal refractive power of 59 eyes was examined before, 3 months and 6 months after myopic LASIK. The refractive power was measured at the corneal apex and at a distance of 2 and 4 mm. Statistical analysis was performed using the Wilcoxon signed rank test; a p value of 0.05 or less was considered statistically significant.At the corneal apex and at a distance of 2 mm the findings with the Keratograph showed a higher refractive power of up to 1.05 D. The differences were statistically significant at all times. At a distance of 4 mm from the corneal apex postoperatively there was no statistically significant difference.The results using the Pentacam system showed a lower corneal refractive power following myopic LASIK at all times. Its measuring principle compared to that of the Keratograph should be preferred when detecting changes of the refractive power of the central cornea after corneal refractive procedures.

In recent years, wavefront analysis has ceased to be purely a laboratory application and emerged as a method used in ophthalmological diagnosis. This development has been promoted mainly by the widespread use of wavefront-guided LASIK (laser in situ keratomileusis). However, aberrometry is still not a common diagnostic technique, and for many ophthalmologists interpretation of the results is difficult. The second part of this serial paper reviews findings that are relevant for the ophthalmological community and highlights current scientific applications in this area.

Lisch corneal dystrophy is an epithelial corneal dystrophy where diffuse gray corneal opacifications are seen in direct illumination that appear in different patterns. Examination in retroillumination shows that these gray changes do consist of multiple densely crowded clear microcysts according to the opacity units. We wanted to investigate if one single case of Lisch corneal dystrophy can be differentiated easily from the other epithelial corneal dystrophies by exact analysis of the opacity units.We examined three non-related patients with Lisch corneal dystrophy at the slit-lamp. The epithelial corneal opacities were documented photographically with direct slit-lamp illumination and retroillumination.All three patients showed the characteristic intraepithelial densely crowded clear microcysts in retroillumination. Diffuse gray radial opacities were noted in both corneas of a 15-year-old female patient. A club-shaped opacity was noted in one cornea of a 35-year-old female patient and a feathery gray opacity pattern was found in one cornea of a 49-year-old male patient. All three patients showed the characteristic densely crowded clear microcysts of Lisch corneal dystrophy in retroillumination.Taking the previous literature into account, five different opacity patterns can be summarised: radial, band, flame/feathery, whorled and club-shaped gray epithelial corneal opacities. A single case of Lisch corneal dystrophy can be differentiated from other epithelial corneal dystrophies by means of an exact analysis of the opacity pattern and units by slit-lamp examination.

Aspherical intraocular lenses (IOLs) are presumed to optimize the optical characteristics of IOLs. In order to profit from these characteristics, exact calculation of the IOL power and good centration of the lens are essential.In all, 43 eyes of 43 patients with an average age of 70.9+/-8.3 years underwent implantation of a Tecnis IOL (AMO, Ettlingen) after uneventful cataract surgery with topical anesthesia. IOL power calculation was performed using the Holladay, Haigis, and SRK II formulas. Spherical equivalent refraction and centration and position of the implanted IOLs were measured 6 months postoperatively. Centration of the IOL was analyzed using digital slit lamp photographs and an image analysis program.Best corrected visual acuity (BCVA) increased from 0.47+/-0.25 (LogMAR) preoperatively to 0.1+/-0.11 6 months postoperatively (spherical equivalent +0.3+/-0.6 D). The intraindividual difference between target refraction and achieved postoperative refraction was 0.64+/-0.11 D for the Holladay formula, -0.21+/-0.11 D for the Haigis formula, and 0.97+/-0.15 D for the SRK II formula. The mean decentration of the IOL from the center of the corneal limbus was 0.4+/-0.1 mm.For the aspherical Tecnis IOL very good postoperative functional results are reported, which are supported by an accurate calculation of the IOL power and a good centration of the IOL inside the capsular bag. In this study the Haigis formula showed the lowest difference between target refraction and achieved postoperative refraction.

Scanning laser tomography (HRT, HRT II), scanning laser polarimetry (GDx nerve fibre analyser, GDx VCC), retinal thickness analyser (RTA) and optical coherence tomography (OCT, stratus OCT) provide objective measurements of the optic disc and the retinal nerve fibre layer suitable for the follow-up of glaucoma patients. Their ability to diagnose early glaucomatous damage is still limited but promising technical advances in this field can be expected in the future. For the moment, clinical examination and fundus photography still remain the gold standard for the assessment of glaucomatous optic disc and retinal nerve fibre layer damage.

In optical rhinometry, the nose is transilluminated with light and the light absorption by the nasal tissue is measured continuously. Using this method, a real time documentation of changes in nasal blood volume is possible. The method has been evaluated using the nasal allergen provocation test. In this study, the ability of optical rhinometry to detect changes in the nasal blood volume due to various posture changes is examined.Optical rhinometry was tested on ten healthy probands, with several examinations being performed on each.By bending the neck, lying down or stopping breathing, stronger light extinction was found. Standing up quickly caused a sudden but short decrease in light extinction. A small amount of exercise, such as making a fist several times, decreased light extinction. Harder exercise on an ergometer led to a stronger decrease in light extinction. In the Valsalva maneuver, an increase in light extinction for the duration of the maneuver was observed. Changes in breathing through the nose or mouth or counting from 1 to 100 had no influence.Using the new method of optical rhinometry, it is possible to detect changes in endonasal blood volume caused by changes of intrathoracic pressure, changes in posture or physical exercise, non-invasively and in real time. This technique can therefore be used for further research on the regulation of the nasal blood flow.

The aim of this prospective study was to investigate accuracy and efficiency of the autorefractometer PowerRefractor compared to established autorefractometers and retinoscopy as standard method.150 patients (300 eyes) were examined. Patients were initially (pupil not influenced) analyzed with the Power Refractor (PR (neutral)). After that a examination followed under standardized Cyclopentolat cycloplegia with the Power Refractor (PR (cyclo)), the hand-held Retinomax K-plus (Nikon), the table-top mounted RK-5 (Canon) and retinoscopy.Deviation from retinoscopy (percentage of values with more than 1 dpt difference/maximal deviation): Sphere: PR (neutral): 66.3 %/8.5 dpt; PR (cyclo): 48 %/5 dpt; RK-5: 26.7 %/4.75 dpt; Retinomax K-plus: 6.7 %/1.25 dpt; Cylinder: PR (neutral): 12 %/6.25 dpt; PR (cyclo): 21 %/4.75 dpt; RK-5: 1.3 %/2.75 dpt; Retinomax K-plus: 2.3 %/2.5 dpt; spherical equivalent: PR (neutral): 44.7 %/7.1 dpt; PR (cyclo): 35.3 %/5.4 dpt; RK-5: 9 %/4.5 dpt; Retinomax K-plus: 1.3 %/1.,4 dpt; error of entire refraction: PR (neutral): 62.7 %/7.8 dpt; PR (cyclo): 61.3 %/7.3 dpt; RK-5: 24 %/4,5 dpt; Retinomax K-plus: 14.7 %/3.6 dptThe best accuracy compared to retinoscopy had Retinomax K-plus followed by RK-5. PowerRefractor had the biggest deviations of the tested devices. PowerRefractor may be a usefull device for screening small children and handicapped people because of the one meter observing distance. For a precise refraction especially in children a retinoscopy under cycloplegic conditions is still necessary.

Foldable intraocular lenses (IOLs) are established in ophthalmic surgery and increasingly more complex geometries are available. This study investigates different designs of the optics of the IOL as well as the imaging quality of these optics utilizing electron microscopic photographs and mathematical approximations.Included in this study were two different lens powers of common IOLs (+ 13 D and + 26 D). All studied IOLs were processed depending upon their water content: Aqueous IOLs with up to 25 % water content were fixed with 2.5 % glutaraldehyde in 0.1 M phosphate buffer (mPP), and then contrasted with 2 % OsO (4) and processed in an alcohol series of 30 - 100 % propanol. Subsequently, the IOLs were transferred into EPON (epoxy resin) and polymerization took place at 60 degrees C. After hardening, the samples were cut out with a leaves saw and divided into halves. Afterwards these were polished with glass and diamond knifes at the ultramicrotom (Ultracut, Rückert-Jung). After coal vaporization measurement took place in the scanning electron microscope (DSM 962, Zeiss). In the case of dry stored IOLs, the samples were sputtered with Au-Pd 20 nm and afterwards measurement was performed as described above. The measurement of the optical imaging quality was performed with correctly and inversely oriented IOLs according to the standard EN ISO 11979 -- 2 by means of a measuring system which works on the basis of the point spread function (PSF) and/or the modulation transfer function (MTF). From this the Strehl ratio was computed in each case.Utilizing a correlation of the electron microscopic investigation of the optics of different IOLs with their imaging quality (Strehl ratio), we were able to show that the optical design of the IOL has substantial influence on the imaging quality of an intraocular lens. In particular, with non-symmetrical designs of the optics (e. g., AR40 e; AMO) the orientation of an IOL in the eye is crucial; i. e., the Strehl ratio increased thereby from 0.68 to 0.87.The design of asymmetrical optics is crucial and much attention should be paid to the fact that the imaging quality can substantially be affected. A correct orientation of the lens within the eye is very important with these asymmetrical optics.

The laser is a well established surgical instrument in lung therapy. This report provides information on the biophysical basics of the laser-induced thermotherapy (LITT) of lung metastases. Optical properties like absorption and scattering determine the penetration depth of laser radiation in tissue. These parameters vary dynamically during the application and define in combination with thermal tissue properties the achievable destruction volume. Parenchyma behaves very differently compared to more dense tissues due to local inhomogenities and the large amount cavaties filled with air. Beside an account of the affecting parameters an overview of therapy options is given. Therapeutic results depend not only on the tissue properties but also on the technical equipment, e.g. the applicator design and the energy applied. Complex dosimetric models allow for a calculation of the lesion's size in advance.

The specific gravity of urine (SG) indicates the number and weight of solute particles in urine; its measurement is helpful in interpreting proteinuria detected by dipstick tests and in monitoring adequate hydration in patients with nephrolithiasis. Four methods for measuring SG or osmolality of urine are currently available (depression of the freezing-point, urometry, refractometry, cation exchange on a reagent strip). Using a recently developed reagent strip, we have measured SG in morning urines of 340 non-selected outpatients and compared the results with SG measurements by refractometry of the same urines. In 86.2% of all urines, a good positive correlation between SG measured by reagent strip and refractometry was noted (r = 0.913, p = 0.0001). In 13.8% of the urines, however, the SG measured by reagent strip deviated by more than +/- 5 from the value obtained by refractometry; in 90% of these urines, glucosuria (reagent strip values too low or too high), proteinuria (values too high), or bacteriuria/leukocyturia (values too low or too high) could be found. In alkaline urine (pH7.0), SG values obtained by reagent strip have to be corrected by +5.

A nomogram for determining the refraction of intraocular lenses was developed to define the following diagnoses: emmetropizing lens, residual refraction of a given lens refraction and desired postoperative refraction. The nomogram makes an approximation solution possible to determine the refractive power of intraocular lenses from the basic refraction and the refractive power of the cornea.

1. The round, oval, or kidney-shaped, radially built spheroliths of the brown or morgagnian cataract show a double refraction in polarized light of about 0.160 optically positive. This is in accordance with Whewellite (calcium oxalate monohydrate). 2. In crystalline cataracts, there are crystals in polarized light with a mean double refraction of 0.046, which is in accordance with cholesterol (C27H48O). 3. In asteroid hyalinosis of the vitreous, the small bodies consisting of needle-shaped crystals arranged in a radial fashion show a small double refraction of 0.012. Therefore the crystal may be brushite (Ca HPO4 X 2 H2O).

The intraocular power of various types of lenses was calculated, based on different anterior chamber depths. If the lens type planned is changed, the lens power also must be altered, therefore, it is necessary to know the individual difference in diopters. For this purpose, a special computer program in BASIC is introduced, in which there is a table that shows the refraction after implantation of different types of lenses. Possibilities for altering this program are also shown.

The Pharmacopoeia of the GDR provides no direct method for the determination of the fat base content in ointments. The indirect determination which is due to in calculating the difference between 100% and the percentages of all the other constituents is tedious and inexact. For this reason, it was tried to find a direct method which was to be reliable, rapid and easy. In principle, the refractometric method divised by Rudischer [2--5, 9] for the determination of fat in meat and meat products, which has been compulsory since 1965, is suitable for this purpose. Consequently, this method was adapted to the requirements of ointment analysis and subjected to modifications which resulted in the variant A for non-ionic ointments, and the variant B for ointments containing ionic fatty alcohol sulphates. The results obtained with the refractometric method from all kinds of ointments tested were in full agreement with the actual fat contents. Parallel determinations differed by 0.5% at the most.