InterCarb: A Community Effort to Improve Interlaboratory Standardization of the Carbonate Clumped Isotope Thermometer Using Carbonate Standards

Increased use and improved methodology of carbonate clumped isotope thermometry has greatly enhanced our ability to interrogate a suite of Earth-system processes. However, interlaboratory discrepancies in quantifying carbonate clumped isotope (Δ47) measurements persist, and their specific sources remain unclear. To address interlaboratory differences, we first provide consensus values from the clumped isotope community for four carbonate standards relative to heated and equilibrated gases with 1,819 individual analyses from 10 laboratories. Then we analyzed the four carbonate standards along with three additional standards, spanning a broad range of δ47 and Δ47 values, for a total of 5,329 analyses on 25 individual mass spectrometers from 22 different laboratories. Treating three of the materials as known standards and the other four as unknowns, we find that the use of carbonate reference materials is a robust method for standardization that yields interlaboratory discrepancies entirely consistent with intralaboratory analytical uncertainties. Carbonate reference materials, along with measurement and data processing practices described herein, provide the carbonate clumped isotope community with a robust approach to achieve interlaboratory agreement as we continue to use and improve this powerful geochemical tool. We propose that carbonate clumped isotope data normalized to the carbonate reference materials described in this publication should be reported as Δ47 (I-CDES) values for Intercarb-Carbon Dioxide Equilibrium Scale.

Diabetic therapeutic effects of ethyl acetate fraction from the roots of Musa paradisiaca and seeds of Eugenia jambolana in streptozotocin-induced male diabetic rats

The folklore medicine of primitive people has been greatly appreciated for centuries. Many researchers study the curative efficiency and mode of action of various medicinal plants. Serum glucose level, lipid profile, glucose tolerance, hepatic and muscle glycogen contents as well as the activities of hepatic hexokinase and glucose-6-phosphatase recovered significantly after oral administration of ethyl acetate fractions of Eugenia jambolana (E. jambolana) or Musa paradisiaca (M. paradisiaca) in separate (E. jambolana L.: 200 mg/kg of body weight and M. paradisiaca: 100 mg/kg of body weight) or combined form for 90 days (twice a day through gavage) to streptozotocin-induced diabetic rats. The loss in body weight of diabetic animals was reversed and serum levels of insulin as well as C-peptide, which were found to be reduced in diabetic rats, increased significantly after oral administration of the fractions. A histological study of the rats' pancreas revealed that after 90 days of oral treatment with the plant fractions in separate or combined form, the size and volume of pancreatic islets in diabetic treated rats increased significantly compared with the diabetic control group. Treatment of diabetic rats with the combined dose (300 mg/kg of body weight) of plant fractions (200 mg E. jambolana and 100 mg M. paradisiaca) was found to be more effective than treatment with the individual fraction. The doses of E. jambolana and M. paradisiaca selected for this study are the optimum antihyperglycemic doses of the plant fractions, which were determined after conducting a dose-dependent study at various dose levels (50-500 mg/kg) in our pilot experiments. The plant fractions were found to be free from metabolic toxicity. Through HPTLC finger printing, three different compounds were noted in the ethyl acetate fraction of E. jambolana L. and eight different compounds in the ethyl acetate fraction of M. paradisiaca L.

Tamm-Horsfall protein in recurrent calcium kidney stone formers with positive family history: abnormalities in urinary excretion, molecular structure and function

Tamm-Horsfall protein (THP) powerfully inhibits calcium oxalate crystal aggregation, but structurally abnormal THPs from recurrent calcium stone formers may promote crystal aggregation. Therefore, increased urinary excretion of abnormal THP might be of relevance in nephrolithiasis. We studied 44 recurrent idiopathic calcium stone formers with a positive family history of stone disease (RCSF(fam)) and 34 age- and sex-matched healthy controls (C). Twenty-four-hour urinary THP excretion was measured by enzyme linked immunosorbent assay. Structural properties of individually purified THPs were obtained from analysis of elution patterns from a Sepharose 4B column. Sialic acid (SA) contents of native whole 24-h urines, crude salt precipitates of native urines and individually purified THPs were measured. THP function was studied by measuring inhibition of CaOx crystal aggregation in vitro (pH 5.7, 200 mM sodium chloride). Twenty-four-hour urine excretion of THP was higher in RCSF(fam) (44.0 +/- 4.0 mg/day) than in C (30.9 +/- 2.2 mg/day, P = 0.015). Upon salt precipitation and lyophilization, elution from a Sepharose 4B column revealed one major peak (peak A, cross-reacting with polyclonal anti-THP antibody) and a second minor peak (peak B, not cross-reacting). THPs from RCSF(fam) eluted later than those from C (P = 0.021), and maximum width of THP peaks was higher in RCSF(fam )than in C (P = 0.024). SA content was higher in specimens from RCSF(fam) than from C, in native 24-h urines (207.5 +/- 20.4 mg vs. 135.2 +/- 16.1 mg, P = 0.013) as well as in crude salt precipitates of 24-h urines (10.4 +/- 0.5 mg vs. 7.4 +/- 0.9 mg, P = 0.002) and in purified THPs (75.3 +/- 9.3 microg/mg vs. 48.8 +/- 9.8 microg/mg THP, P = 0.043). Finally, inhibition of calcium oxalate monohydrate crystal aggregation by 40 mg/L of THP was lower in RCSF(fam) (6.1 +/- 5.5%, range -62.0 to +84.2%) than in C (24.9 +/- 6.0%, range -39.8 to +82.7%), P = 0.022, and only 25 out of 44 (57%) THPs from RCSF(fam )were inhibitory (positive inhibition value) vs. 25 out of 34 (74%) THPs from C, P < 0.05. In conclusion, severely recurrent calcium stone formers with a positive family history excrete more THP than healthy controls, and their THP molecules elute later from an analytical column and contain more SA. Such increasingly aggregated THP molecules predispose to exaggerated calcium oxalate crystal aggregation, an important prerequisite for urinary stone formation.

Furanoid sugar amino acids as dipeptide mimics in design of analogs of vasoactive intestinal peptide receptor binding inhibitor

In this study we describe the development of peptidomimetic analogs of the potent vasoactive intestinal peptide receptor binding inhibitor, Leu(1) -Met(2) -Tyr(3) -Pro(4) -Thr(5) -Tyr(6) -Leu(7) -Lys(8) -OH 1, by incorporating furanoid sugar amino acids (SAAs) 2-4 into the molecule. The furanoid SAAs 2-4 were used as dipeptide isosteres to replace Tyr(3) -Pro(4) or Pro(4) -Thr(5) in sequence 1. The resulting analogs 5-9 were tested for their anti-cancer activities in vitro, following the standard MTT assay on a panel of human cancer cell lines. One of the potent analogs, 6a was tested in vivo for tumor regression on primary colon tumor xenografted nude mice. Our experimental results suggest that many of these analogs show either retention or enhancement of biological activity.

Undetected cardiogenic shock in patients with congestive heart failure presenting to the emergency department

The purpose of this study was to examine the use of lactic acid levels and continuous central venous oxygen saturation (central venous oximetry) to stratify and treat patients with acutely decompensated end-stage chronic congestive heart failure (CHF) presenting to the emergency department. This prospective, convenience, non-outcome study was performed at an urban tertiary care hospital. Patients with end-stage CHF with an ejection fraction <30% presenting in decompensated CHF were eligible for the study. Patients were assessed using the Killip classification and New York Heart Association criteria. After lactic acid levels were obtained, patients were managed according to a standardized protocol guided by central venous oximetry. The patients were divided into high lactic acid (n = 22), low lactic acid (n = 5), and control groups (stable patients presenting to a cardiology clinic, n = 17) for comparison. There was no statistical difference in vital signs, or Killip and New York Heart Association criteria among the 3 groups. Central venous oxygen saturation was significantly lower in the high lactic acid group (32 +/- 12%) than in the normal lactic acid (51 +/- 13%) and control groups (60 +/- 6%) (p < 0.001). After treatment there was a significant decrease in lactic acid (-3.65 +/- 3.65 mM/L) and an increase in central venous oxygen saturation (32 +/- 13%) in the high lactic acid group compared with the normal lactic acid group (p < 0.001). A significant subset of patients with decompensated end-stage CHF present to the emergency department in occult shock and are clinically indistinguishable from patients with mildly decompensated CHF and stable CHF. Once identified, these patients require aggressive alternative management and disposition. Further study is necessary to identify whether this intervention impacts morbidity, mortality, and health care resource consumption.

Ultrastructure of intermediate trophoblast cells during morphogenesis of syncytiotrophoblast in early human pregnancy

During human embryonic development the process of differentiation begins in the cells covering the blastocyst, resulting in the formation of outer syncytial and inner cytotrophoblastic cell layers. Although the outer syncytial layer is known to be derived from the underlying layer of mononuclear cytotrophoblasts, the cellular mechanism involved in its morphogenesis is not clear. Furthermore, there is another type of cells, designated as intermediate trophoblasts, which play a vital role in syncytium formation. Using early first-trimester (6-10 weeks' gestation) human chorionic villi, a study was carried out to illustrate the ultrastructural features of these cells. It was observed that while there was a large number of coated vesicles, vacuoles, lysosomes and dense granules in the syncytiotrophoblast, in cytotrophoblasts there was a relatively smaller number. In intermediate cells, however, these organelles were more abundant. Moreover, a discontinuity in the plasma membrane along with gap junctions was frequently observed in these cells. Since these features represent the transitional stage of a differentiating cell, it is possible that the syncytiotrophoblast is in fact formed by the differentiation of intermediate trophoblasts.

Ultrastructure of cellular components of human trophoblasts during early pregnancy

Two cell types, the cyto- and syncytio-trophoblasts, were identified in human chorionic villi of 6-10 weeks' gestation. The intracellular organization of these cells was examined. Ultrathin sections of small pieces of chorionic villi revealed the presence of a multinucleate syncytiotrophoblastic layer, whose surface was covered with microvilli. The cytotrophoblasts, however, had a single large nucleus with a prominent nucleolus. An interesting feature of the basement membrane of these cells was the presence of aggregates of dark granules in samples of the earlier gestational age (6-8 weeks) and granular bodies having a dense outer ring and a translucent inner ring with a lucid central area in samples of 8-10 weeks' gestation. Both types of granules are mineralized and are assumed to perform a buffering role for maintaining the neutrality of the layer.

New, sensitive and specific ELISA for the detection of neuropeptides in culture supernatants

Accurate and sensitive sandwich ELISA has been developed for the detection and identification of each of the three neuropeptides, namely, Vasoactive intestinal peptide, Somatostatin and Substance P. The neuropeptides conjugated with BSA and emulsified with Freund's adjuvant were used for immunisation of rabbits. Titres of polyclonal antibodies were checked by indirect immunofluorescence. The animals were bled when titres were high, sera separated, complement inactivated and IgG class of antibodies were purified using a protein G column. Purified IgG antibodies were used for coating the wells and for conjugation with HRPO and used for the detection of the synthetic neuropeptides in a standard solution or in the culture supernatant. The ELISA thus developed for the assay of each of the three neuropeptides had a sensitivity (0.01 ng - 12.8 ng/ml) equal to or better than that reported for these peptides by radioimmunoassay. The assay was highly specific and did not react with a panel of other neuropeptides tested. High level of sensitivity without compromising the specificity was achieved by using activated polyvinyl plates and using purified IgG from high titre rabbit anti-peptide sera. The non specific reaction was minimised by using 10,000 MW cut off amicon filtered supernatants.

Study of genetics, epidemiology, and vitamin usage in familial spina bifida in the United States in the 1990s

We analyzed family structure, genetic patterns, epidemiology, and vitamin usage in a series of families with multiple cases of spina bifida (familial SB). Among 6,491 individuals ascertained in 72 families with familial SB, we identified 180 patients--85 males and 95 females. The number of collateral cases on the maternal side (49 of 3,588), analyzed by category of kinship, were significantly higher than those on the paternal side (16 of 2,903) (p = 0.0002). Genomic imprinting or a partial mitochondrial contribution are possible mechanisms for this maternal effect. The proportion of US-born SB families reporting some Irish ancestry (49%, 34 of 70) or some German ancestry (50%, 35 of 70) were significantly higher than those for the US population at large. In contrast, the proportion of families reporting some African-American ancestry (1%, 1 of 70) was significantly lower. The elevated proportions of families with Irish and German ancestry, the high frequency of SB in Northern Ireland and in certain regions of Germany, the reduced proportion of families with African-American ancestry, and the lower prevalence of SB in African-Americans all suggest a genetic contribution to the etiology of the disorder. In our study, the proportion of mothers who used supplemental vitamins during the periconceptional period (29%, 47 of 163) was not significantly different from that in the US population at large.

Radioimmunoassay and automated enzyme immunoassay for the determination of thyroxine

The EMIT homogeneous enzyme immunoassay for the determination of thyroxine (T4) was adapted to an automatic analyser (Type Kem-O-Mat) and compared with a conventional radioimmunoassay. Sera from 92 patients whose thyrometabolic status was being examined, and control sera with 3 different T4 concentrations were analysed by both methods. Day-to-day analyses of the control sera gave variation coefficients between 6 and 10% for both methods. The mean value for T4 in the patients sera was 111 nmol/l (8.6 microgram/dl) determined by the enzyme immunoassay and 109 nmol/l (8.5 microgram/dl) determined by the radioimmunoassay; the correlation coefficient was r = 0.9.