P-776 Maternal and neonatal outcomes of singletons and twins after frozen-thawed embryo transfer in different cycle regimes: Increased risks of hypertensive disorders in Hormone replacement cycles

Study question

What are the associations between cycle regime and maternal and neonatal outcomes after frozen-thawed embryo transfer leading to singleton or twin life birth?

Summary answer

Hormone replacement cycles are associated with higher and natural or low-dose stimulation with lower risks for bleeding, hypertension and preeclampsia in singleton and twin pregnancies.

What is known already

So far, there is no consensus on optimal cycle regimen for endometrial preparation: Frozen-thawed embryo transfers can be either performed in Natural Cycles (NC-FET), low-dose Stimulation Cycles (SC-FET) or Hormone Replacement Cycles (HRC-FET). In previous studies, HRC-FET was shown to be associated with an increase of serious maternal and neonatal complications, i.e. preeclampsia (doubled to tripled risk), postpartum hemorrhage (doubled risk), placenta accrete (sixfold risk), post-term birth (sixfold risk) and Caesarean section (doubled risk) compared to NC-FET or SC-FET. These results indicate that risks are increased in cycles in which the development of follicles and luteal bodies is medically inhibited.

Study design, size, duration

Retrospective cohort study analyzing a total of 4636 singletons and also 544 twins born after FET that were registered in the Swiss IVF Registry from 2014 to 2019.

Participants/materials, setting, methods

Women were divided into three groups according to the cycle regimes: NC-FET (n = 776), SC-FET (n = 758) and HRC-FET (n = 3646) leading to life birth. Maternal outcomes included pregnancy complications such as bleedings, isolated hypertension (>140/90 mmHg) and preeclampsia. Neonatal outcomes comprised gestational age and weight, mode of delivery and neonatal status.

Incidences were compared using Fisher exact or Chi-square tests. Multivariate mixed model analysis was performed for singleton and twin pregnancies.

Main results and the role of chance

In singleton pregnancies, the incidences of bleeding in first trimester (NC: 2.8%, SC: 2.6%, HRC: 7.0%; p<.001), isolated hypertension (NC: 0.9%, SC: 0.2%, HRC: 1.8%; p = <.001) and preeclampsia (NC: 1.7%, SC: 0.3%, HRC: 2.8%, p<.001) were significantly higher in HRC-FET. Gestational diabetes occurred most (NC: 4.6%, SC: 7.0%, HRC: 4.5%; p = 0.032) and intrauterine growth restriction least frequently (NC: 1.9%, SC: 0.2%, HRC: 1.3%; p = 0.004) in SC-FET. Highest spontaneous birth rates were reported in NC-FET (NC: 51.2%, SC: 45.0%, HRC: 33.8%; p<.001). Multivariate analysis revealed doubled odds ratio of bleeding in first trimester (aOR 2.01; 95% CI 1.20-3.37; p = 0.008%) and preeclampsia (aOR 2.13; 95% CI 1.12-4.05; p = 0.021) in HRC-FET vs. NC-FET and sixfold odds ratio of preeclampsia in HRC-FET vs. SC-FET (aOR 6.37; 95% CI 1.48-27.54; p = 0.013). Outcomes of SC-FET and NC-FET were comparable.

In twin pregnancies, the incidences of preeclampsia were significantly higher in HRC-FET (NC: 2.7%, SC: 1.0%, HRC: 7.2%, p = 0.026). There were no differences in delivery mode between cycle regime. Multivariate analysis revealed numerically higher odds ratio of preeclampsia in HRC-FET vs. NC-FET (aOR 2.57; 95% CI 0.55 - 12.07; p = 0.232) and in HRC-FET vs. SC-FET (aOR 4.07; 95% CI 0.47 - 34.91; p = 0.2) but without reaching significance.

Limitations, reasons for caution

The data were drawn from a registry analysis with limited information on patients’ characteristics. Data such as BMI were not available. As the study is based on a register analysis, some errors in data collection cannot be excluded.

Wider implications of the findings

This is the first large register study to demonstrate a clear association between the three different cycle regimes and pregnancy complications both in singleton and twin pregnancies. HRC-FET showed the highest maternal risks of hypertensive disorders, therefore, it should be avoided and replaced by SC-FET or NC-FET if medically possible.

Trial registration number

Not applicable.

P-391 Early pregnancy complications after frozen-thawed embryo transfer in different cycle regimes: Increased risks for miscarriages and bleedings in Hormone replacement cycles

Study question

What are the associations between cycle regime and early pregnancy complications after frozen-thawed embryo transfers and what are the respective life birth rates per pregnancy?

Summary answer

Hormone replacement cycles are associated with doubled odd ratios of bleedings and miscarriages <12 weeks leading to lowest life birth rates (LBR) per pregnancy (68.2%).

What is known already

So far, there are only few studies which analysed both, the associations between cycle regime and early pregnancy complications as well as life birth rates (LBR) per pregnancy after frozen-thawed embryo transfer (FET). In 2017, a Cochrane analysis did not find sufficient evidence to support the use of a specific cycle regimen in preference to another since there were only four direct comparisons. In 2021, a network meta-analysis including 26 RCTs and 113 cohort studies revealed lowest LBR in hormone replacement cycles compared with other endometrial preparation protocols but without stating the reasons for the lowest LBR.

Study design, size, duration

Retrospective cohort study analyzing a total of 7342 pregnancies after FET that were registered in the Swiss IVF Registry from 2014 to 2019.

Participants/materials, setting, methods

Women were divided into three groups according to the different cycle regimens: Natural Cycles (NC-FET, n = 998), low-dose Stimulation Cycles (SC-FET, n = 984) and Hormone Replacement Cycles (HRC-FET, n = 5360) leading to pregnancy. Outcomes included early pregnancy complications such as bleedings, miscarriages and ectopic pregnancies, deliveries (including intrauterine deaths) and LBR. Incidences were compared using Fisher exact and Chi-square tests. Multivariate mixed model analysis with pregnancy complications as outcome was performed.

Main results and the role of chance

The incidences of bleeding in first trimester (NC: 3.5%, SC: 4.3%, HRC: 8.4%; p<.001) and miscarriage <12 weeks (NC: 19.0%, SC: 19.7%, HRC: 29.1%; p<.001) were significantly higher in HRC-FET.

Multivariate analysis revealed doubled odds ratio of bleedings in first trimester (aOR 1.92; 95% CI 1.30-2.81; p<.001) and miscarriages <12 weeks (aOR 1.82; 95% CI 1.51-2.19; p<.001) in HRC-FET vs. NC-FET. There were comparable odds ratio in HRC-FET vs. SC-FET and no differences between NC-FET vs. SC-FET. Highest LBR per pregnancy (NC: 78.0%, SC: 77.2%, HRC: 68.2%%; p<.001) was reported in NC-FET.

Limitations, reasons for caution

The data were drawn from a registry analysis with limited information on patients’ characteristics. Data such as BMI were not available. As the study is based on a register analysis, some errors in data collection cannot be excluded.

Wider implications of the findings

This is the latest large European register study evaluating early pregnancy complications and LBR per pregnancy after FET by cycle regime. Miscarriage rate was highest in HRC-FET which can be translated into lower LBR. Thus, HRC-FET should be avoided if medically possible, to achieve better pregnancy outcomes.

Trial registration number

Non required

Influence of Power Law and Isothermal Simplification on the Accuracy in Single Screw Extrusion

For the mathematical modeling of single screw extruders crucial simplifications are frequently made. In order to estimate the quality of these models it is necessary to evaluate the differences resulting from these simplifying presumptions. This study refers to the influence of two frequently used simplifications, the power-law model and the assumption of an isothermal flow.

The differences due to the application of the power-law show an evident dependency on the descriptive material parameters. Depending on the Nahme-number the isothermal simplification proves partly clear differences from non-isothermal flows. These differences however are considerably reduced in the range of high Péclet-numbers.

Genome-wide Gene-by-Sex Interaction Studies Identify Novel Nonsyndromic Orofacial Clefts Risk Locus

Risk loci identified through genome-wide association studies have explained about 25% of the phenotypic variations in nonsyndromic orofacial clefts (nsOFCs) on the liability scale. Despite the notable sex differences in the incidences of the different cleft types, investigation of loci for sex-specific effects has been understudied. To explore the sex-specific effects in genetic etiology of nsOFCs, we conducted a genome-wide gene × sex (GxSex) interaction study in a sub-Saharan African orofacial cleft cohort. The sample included 1,019 nonsyndromic orofacial cleft cases (814 cleft lip with or without cleft palate and 205 cleft palate only) and 2,159 controls recruited from 3 sites (Ethiopia, Ghana, and Nigeria). An additive logistic model was used to examine the joint effects of the genotype and GxSex interaction. Furthermore, we examined loci with suggestive significance (P < 1E-5) in the additive model for the effect of the GxSex interaction only. We identified a novel risk locus on chromosome 8p22 with genome-wide significant joint and GxSex interaction effects (rs2720555, p_2df = 1.16E-08, p_GxSex = 1.49E-09, odds ratio [OR] = 0.44, 95% CI = 0.34 to 0.57). For males, the risk of cleft lip with or without cleft palate at this locus decreases with additional copies of the minor allele (p < 0.0001, OR = 0.60, 95% CI = 0.48 to 0.74), but the effect is reversed for females (p = 0.0004, OR = 1.36, 95% CI = 1.15 to 1.60). We replicated the female-specific effect of this locus in an independent cohort (p = 0.037, OR = 1.30, 95% CI = 1.02 to 1.65), but no significant effect was found for the males (p = 0.29, OR = 0.86, 95% CI = 0.65 to 1.14). This locus is in topologically associating domain with craniofacially expressed and enriched genes during embryonic development. Rare coding mutations of some of these genes were identified in nsOFC cohorts through whole exome sequencing analysis. Our study is additional proof that genome-wide GxSex interaction analysis provides an opportunity for novel findings of loci and genes that contribute to the risk of nsOFCs.

Dental Caries Severity and Nutritional Status of Nigerian Preschool Children

INTRODUCTION

Malnutrition in children is one of the most prevalent global health challenges, and malnourished children have a higher risk of death from childhood diseases. Early childhood caries (ECC) is the most common chronic disease of childhood. Complications from ECC such as pain, loss of tooth/teeth, and infection can undermine a child's nutrition and growth.

AIM

This study aims to evaluate the severity of decay, missing, and filled tooth (dmft) by nutritional status using the z scores of the anthropometric measurements: height for age (HFA), weight for age (WFA), weight for height (WFH), and body mass index for age (BMIA) among children with ECC in Nigeria.

STUDY DESIGN

This is a cross-sectional study conducted in 5 local government areas (LGAs) in Lagos State, Nigeria. A multistage sampling technique was used.

RESULTS

A total of 273 cases of ECC were included in the analyses (mean age 4.19 ± 0.96 y). Overall, the mean dmft was 3.04 ± 2.28, and most (96%) were accounted for by untreated decay. The distribution of dmft within the different z score categories of BMIA (<-3 = severely wasted, -2 to -3 = wasted, -2 to +2 = normal, +2 to +3 = overweight and >+3 = obese) showed the highest dmft scores among the combined severely wasted and wasted groups, lowest among children with normal z scores, and intermediate in the overweight and obese groups. There was a significant negative correlation between BMIA z score, WFH z score, and dmft (r = -0.181, P < 0.05 and r = -0.143, P < 0.05, respectively). However, the correlations between HFA z score, WFA z score, and dmft were positive but not significant (r = 0.048, P = 0.44 and r = 0.022, P = 0.77, respectively).

CONCLUSION

Our study showed an increased severity of dental caries among severely wasted or wasted children with ECC compared to those of normal or overweight.

KNOWLEDGE TRANSFER STATEMENT

The results from this study will raise awareness among clinicians and policy makers on the need for a primary prevention program for early childhood caries in countries with high burden of malnutrition and limited resources. Also, it will help draw the attention of clinicians to the caries status of malnourished children that can be managed to improve the nutritional outcomes.

Recovery of menses after functional hypothalamic amenorrhoea: if, when and why

BACKGROUND

Prolonged amenorrhoea occurs as a consequence of functional hypothalamic amenorrhoea (FHA) which is most often induced by weight loss, vigorous exercise or emotional stress. Unfortunately, removal of these triggers does not always result in the return of menses. The prevalence and conditions underlying the timing of return of menses vary strongly and some women report amenorrhoea several years after having achieved and maintained normal weight and/or energy balance. A better understanding of these factors would also allow improved counselling in the context of infertility. Although BMI, percentage body fat and hormonal parameters are known to be involved in the initiation of the menstrual cycle, their role in the physiology of return of menses is currently poorly understood. We summarise here the current knowledge on the epidemiology and physiology of return of menses.

OBJECTIVE AND RATIONALE

The aim of this review was to provide an overview of (i) factors determining the recovery of menses and its timing, (ii) how such factors may exert their physiological effects and (iii) whether there are useful therapeutic options to induce recovery.

SEARCH METHODS

We searched articles published in English, French or German language containing keywords related to return of menses after FHA published in PubMed between 1966 and February 2020. Manuscripts reporting data on either the epidemiology or the physiology of recovery of menses were included and bibliographies were reviewed for further relevant literature. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria served to assess quality of observational studies.

OUTCOMES

Few studies investigate return of menses and most of them have serious qualitative and methodological limitations. These include (i) the lack of precise definitions for FHA or resumption of menses, (ii) the use of short observation periods with unsatisfactory descriptions and (iii) the inclusion of poorly characterised small study groups. The comparison of studies is further hampered by very inhomogeneous study designs. Consequently, the exact prevalence of resumption of menses after FHA is unknown. Also, the timepoint of return of menses varies strongly and reliable prediction models are lacking. While weight, body fat and energy availability are associated with the return of menses, psychological factors also have a strong impact on the menstrual cycle and on behaviour known to increase the risk of FHA. Drug therapies with metreleptin or naltrexone might represent further opportunities to increase the chances of return of menses, but these require further evaluation.

WIDER IMPLICATIONS

Although knowledge on the physiology of return of menses is presently rudimentary, the available data indicate the importance of BMI/weight (gain), energy balance and mental health. The physiological processes and genetics underlying the impact of these factors on the return of menses require further research. Larger prospective studies are necessary to identify clinical parameters for accurate prediction of return of menses as well as reliable therapeutic options.

Developing an Electronic Medical Record for Interlinked Care Services in Haiti

A large clinical care and research organization in Haiti required an electronic medical record system (EMR) to serve the needs of its 30 interlinked clinical programs. After assessing available open source software, the local team designed and implemented a modular proprietary EMR that is improving data quality and patient care. Despite the many benefits of existing open source medical record systems, clinical centers with complex workflow patterns--even those in resource-limited settings--should consider developing sustainable, local systems that fit their care model.

Investigations into Kinematic Reversal in Non-isothermal Flows in Single-screw Machines

When describing the flow in single-screw machines in mathematical terms, the screw is generally assumed to be standing still inside a rotating barrel. This study looks into whether and, if so, how far this principle of kinetic reversal falsifies the calculation result. It is performed both on an analytical basis and with the aid of comparative FEA simulations, taking the general case of a non-isothermal flow. It is shown that both kinematic boundary conditions lead to absolutely identical calculation results.

Blood pressure and pulse response to insulin-induced hypoglycemia during non-selective and selective beta-blockade

Hypoglycemia was induced in ten healthy male volunteers during medication with atenolol, metoprolol and propranolol. The beta-blockers abolished the tachycardia during hypoglycemia. In some subjects bradycardia, and in two nodal bradycardia was observed on propranol. The physiologic blood pressure responses were dampend during the beta1-selective blockade. With propranolol a rise in blood pressure was recorded, in two subjects up to 160/105. The blockers had no effect on degree of hypoglycemia or glucose recovery.

Dog-associated risk factors for human plague

Plague is a rare but often fatal zoonosis endemic to the western United States. Previous studies have identified contact with pets as a potential risk factor for infection. We conducted a matched case-control study to better define the risks associated with pets at both the household and individual levels. Using a written questionnaire, we surveyed nine surviving plague patients, 12 household members of these patients, and 30 age- and neighbourhood-matched controls about household and individual exposures. Overall, 79% of households had at least one dog, 59% had at least one cat and 33% used flea control, with no significant differences between case and control households. Four (44%) case households reported having a sick dog versus no (0%) control households [matched odds ratio, (mOR) 18.5, 95% confidence interval (CI) 2.3-infinity], and four (44%) patients reported sleeping in the same bed with a pet dog versus three (10%) controls (mOR 5.7, 95% CI 1.0-31.6). Within case households with multiple members, two (40%) of five patients slept with their dogs versus none (0%) of 12 healthy family members (P=0.13). The exposures to cats were not significant. Sleeping in the same bed as a pet dog remained significantly associated with infection in a multivariate logistic regression model (P=0.046). Our findings suggest that dogs may facilitate the transfer of fleas into the home and that activities with close extended contacts with dogs may increase the risk of plague infection.

CSF findings in 250 patients with serologically confirmed West Nile virus meningitis and encephalitis

OBJECTIVE

To provide a large, comprehensive evaluation of the CSF findings in patients with serologically confirmed West Nile virus (WNV), CNS disease, and their correlation with outcome.

METHODS

CSF samples from 334 WNV-infected hospitalized patients were analyzed. Information was available and extracted from the medical records of 250 of these patients, and CSF parameters correlated with clinical and epidemiologic features of disease (e.g., patient age, sex, outcome).

RESULTS

Patients with meningitis had a mean of 226 cells/mm3, and those with encephalitis had a mean of 227 cells/mm3. Three percent of meningitis patients and 5% of encephalitis patients had fewer than 5 cells/mm3, and approximately 8% of both groups had more than 500 cells/mm3. Patients with meningitis had a mean of 41% neutrophils, and those with encephalitis had 45%. Forty-five percent of meningitis patients and 37% of encephalitis patients had at least 50% neutrophils in their initial CSF specimen. Neither the mean percent neutrophils nor their distribution differed significantly between groups. Forty-seven percent of encephalitis patients and 16% of meningitis patients had CSF protein of 100 mg/dL or greater (p < 0.01). Although specific CSF parameters, including nucleated cell count and protein concentration, correlated significantly with outcome, multivariate analysis suggested that their total predictive value was modest. Age was an additional predictor of outcome independent of CSF variables in all patients.

CONCLUSIONS

Serologically confirmed West Nile virus meningitis and encephalitis produce similar degrees of CSF pleocytosis and are frequently associated with substantial CSF neutrophilia. Patients with encephalitis have higher CSF protein concentrations and are more likely to have adverse outcomes, including admission to long-term care facilities or even death after their acute illness. CSF findings were only a modest predictor of disease outcome, with patient age adding important independent prognostic information.

Comparison of three commercial systems for identification of yeasts commonly isolated in the clinical microbiology laboratory

We evaluated three commercial systems (RapID Yeast Plus System; Innovative Diagnostic Systems, Norcross, Ga.; API 20C Aux; bioMerieux-Vitek, Hazelwood, Mo.; and Vitek Yeast Biochemical Card, bioMerieux-Vitek) against an auxinographic and microscopic morphologic reference method for the ability to identify yeasts commonly isolated in our clinical microbiology laboratory. Two-hundred one yeast isolates were compared in the study. The RapID Yeast Plus System was significantly better than either API 20C Aux (193 versus 167 correct identifications; P < 0.0001) or the Vitek Yeast Biochemical Card (193 versus 173 correct identifications; P = 0.003) for obtaining correct identifications to the species level without additional testing. There was no significant difference between results obtained with API 20C Aux and the Vitek Yeast Biochemical Card system (P = 0.39). The API 20C Aux system did not correctly identify any of the Candida krusei isolates (n = 23) without supplemental testing and accounted for the major differences between the API 20C Aux and RapID Yeast Plus systems. Overall, the RapID Yeast Plus System was easy to use and is a good system for the routine identification of clinically relevant yeasts.

AIDS in Haiti: 1982-1992

Haiti was one of the first countries where AIDS was recognized, a burden that led to the stigmatization of an entire nation resulting in serious long-term economic, social, and psychological consequences. Sixty percent of urban hospital beds are now occupied by patients infected with human immunodeficiency virus (HIV). AIDS is the leading cause of death in sexually active adults and increasingly has become a disease of women and children. AIDS threatens to reverse the decrease in infant mortality achieved during the past decade. In spite of educational efforts, the "silent epidemic" continues in all parts of the country and within all strata of society. The current HIV seroprevalence is 10% in urban areas and 5% in rural areas. AIDS is known but not understood; counseling modifies behavior in only 10%-20% of at-risk persons. This distressing situation is likely to worsen in view of the ongoing political crisis since almost all AIDS-education programs are dependent on foreign support.

Forces acting during air and ground transport on patients stabilized by standard immobilization techniques

OBJECTIVE

Transportation, whether by air or ground, exposes the injured patient to mechanical shocks and vibrations. These forces and their hazardous potential remain largely unknown. The purpose of this study was to identify, characterize, and compare the forces generated during patient transport in helicopter and ground ambulances.

METHODS

Forces generated during transport were measured using an instrumented, low mass triaxial accelerometer fixed to a standard backboard. Measurements were recorded in three axes with an adult subject immobilized on the board during experimental ambulance and helicopter trials. Acceleration waveforms were analyzed in each mode of transport.

RESULTS

Forces for both ground and air transport ranged 0.07g to 0.19g root mean square, and 0.32g to 0.83g mean peak. The vibrational forces in the helicopter were fairly discrete, located at 6.6, 19.5, and 39 Hz, and axis dependent. Ground ambulance vibrations were more diffuse, occurring below 1 Hz and between 10 and 15 Hz. Crest factor analysis shows that shocks were more uniform in the helicopter than on the ground, especially in the anterior-posterior axis.

CONCLUSION

These data suggest that transportation by helicopter subjects supine patients to greater lateral and vertical forces, but smaller head to toe forces, than ground transportation (P less than .05). In general, the forces to which a backboarded subject is subjected during transport range from 0.32g to 0.83g, vary by direction, and are more predictable for air than for ground transport. The clinical significance of these measurements requires further study.

Meningococcal septicaemia treated with combined plasmapheresis and leucapheresis or with blood exchange

Mortality among patients suffering from meningococcal septicaemia has reached nearly 50% in parts of northern Norway despite intensive care. The activation of complement and blood cells by endotoxin is assumed to be the cause of most of the associated pathophysiological changes. Consequently, it would seem logical to remove such constituents either by combined plasmapheresis and leucapheresis or by blood exchange in patients with a fatal prognosis. Three patients were treated with plasmapheresis and leucapheresis and one with blood exchange. All recovered without sequelae, and no complications or serious problems caused by these procedures were observed. It is concluded that either combined leucapheresis and plasmapheresis or blood exchange is well tolerated and a valuable supplement to conventional intensive care in fulminant meningococcal septicaemia.

Effect of posture on ampicillin pharmacokinetics, glomerular filtration rate and renal plasma flow in resting subjects

Differences in drug kinetics between supine rest and ambulation have been reported, but the relative contribution of postural changes and changes in the level of physical activity has not been evaluated. Ampicillin pharmacokinetics, glomerular filtration rate (GFR) and renal plasma flow (RPF) were studied in six male volunteers at rest in the sitting and lying position with an interval of 1 week. After intravenous administration ampicillin kinetics, analyzed according to a two-compartment open model, demonstrated significant changes in drug distribution when the position was changed from lying to sitting: alpha-increased by 50%, V1 and V beta increased by 19% and 22% respectively. Ampicillin clearance, the fraction of dose recovered from urine, GFR and RPF were, however, not influenced by the change in posture. Our data on effects of posture in resting subjects suggest that previously reported differences in drug elimination and RPF between lying and ambulatory subjects are largely due to differences in the level of physical activity.

The effect of blood transfusions on renal transplantation. Studies of 395 patients registered for transplantation with a first cadaveric kidney

Three-hundred-and-ninety-five candidates registered for a first cadaveric renal transplant have been analyzed for the effect of pre-graft blood transfusions. Of these, 348 patients were transplanted, 45 died prior to transplantation and two patients have not yet received a transplant. Slightly less than half of the transplanted patients had been transfused, and those received five or more transfusions demonstrated a superior graft survival. This was pronounced in all HLA incompatible transplants who had received five or more transfusions. In patients who received less than five transfusions, only one-two HLA antigen incompatible transplants demonstrated increased graft survival. The frequency of rejection episodes was significantly decreased in all transfused compared to non-transfused groups. Among the patients dying while waiting for a transplant, the majority had been transfused, and a significantly higher proportion of them had cytotoxic HLA antibodies, compared to those who were transplanted.

Effect of blood transfusions on renal transplantation: study of 191 consecutive first transplants from living related donors

One hundred ninety-one consecutive living related transplants performed from 1969 to the end of 1978 have been analyzed for the effect of pretransplant blood transfusions. Superior graft survival was observed in transfused patients transplanted with a one HLA haplotype-disparate kidney, whereas no effect of blood transfusions could be observed on the survival of HLA-identical transplants. The frequency of first rejection episodes was significantly reduced in transfused compared to nontransfused one haplotype-mismatched transplants, while no influence of blood transfusions was seen in patients with HLA-identical transplants. The survival of patients was, however, not influenced by previous transfusions. Pretransplant hemodialysis improved graft survival and patient survival; the difference was, however, only significant at 2 years in the one haplotype-mismatched group. When analyzed separately, both blood transfusions and hemodialysis had a beneficial effect on graft survival in one haplotype-mismatched transplants.

[Calculation of radioimmunochemical determinations by "spline approximation" (author's transl)]

A simplified method, based on the "spline approximation", is reported for the calculation of the standard curves of radioimmunochemical determinations. It is possible to manipulate the mathematical function with a pocket calculator, thus making it available for a large number of users. It was shown that, in contrast to the usual procedures, it is possible to achieve optimal quality control in the preparation of the standard curves and in the interpolation of unknown plasma samples. The recaluculation of interpolated values from their own standard curve revealed an error of 4.9% which would normally be an error of interpolation. The new method was compared with two established methods for 8 different radioimmunochemical determinations. The measured values of the standard curve showed a weighting, and there was a resulting quality control of these values, which, according to their statistical evalution, were more accurate than those of the others models (Ekins et al., Yalow et al., (1968), in: Radioisotopes in Medicine: in vitro studies (Hayes, R. L., Goswitz, F.A. & Murphy, B. E. P., eds) USA EC, Oak Ridge) and Rodbard et al. (1971), in: Competitive protein Binding Assys(Odell, W. D. & Danghedy, W. H., eds.) Lipincott, Philadelphia and Toronto). In contrast with these other models, the described method makes no mathematical or kinetic preconditions with respect to the dose-response relationship. To achieve optimal reaction conditions, experimentally determined reaction data are preferable to model theories.

Total and free triiodothyronine and thyroid-binding globulin concentration in elderly human persons

Total thyroxine (TT4) and triiodothyronine (TT3) were found to be low in healthy elderly subjects with a preferential decrease of triiodothyronine. In order to determine the importance of these findings 22 healthy elderly subjects were examined. Free triiodothyronine (FT3), thyroid binding globulin (TBG) concentration and basal thyroid stimulating hormone (TSH) were measured by radioimmunoassay. Liver enzymes, cholesterol and total protein concentration were also assayed. TBG was significantly increased compared to a middle-aged group and did not correlate with TT4, TT3 and TSH. Basal TSH values were in the normal range and could be detected in all the elderly subjects in contrast to undetectable values in 40% of the younger subjects. FT3 determined directly did not correlate with the values calculated according to the law of mass action. According to the FT3 values the elderly subjects could be subdivided into three groups independent of their TT4, TT3, TBG and TSH values. FT3 was undetectable in one group, in the low normal to normal range in another and elevated in the third group. Our results suggest that 1) there is no correlation between TT4, TT3, elevated TBG and FT3 determined directly or by calculation, 2) basal TSH values seem to indicate possible hypothyroidism in elderly persons which is correlated with elevated cholesterol levels and 3) FT3 measured directly subdivides this metabolic state into three groups possibly depending on the intracellular concentration of T4.