Electronic effects promoted the catalytic activities of binuclear Co(II) complexes for visible-light-driven CO2 reduction in a water-containing system

Under the action of a catalyst, the photoinduced reduction of CO₂ to chemicals and fuels is one of the greenest and environment-friendly approaches for decreasing atmospheric CO₂ emissions. Since the environment was affected by the greenhouse effect, scientists have never stopped exploring efficient photoinduced CO₂ reduction systems, particularly the highly desired non-noble metal complexes. Most of the currently reported complexes based on non-noble metals exhibit low catalytic activity, selectivity, and stability in aqueous systems under the irradiation of visible light. Herein, we report a new binuclear cobalt complex [Co₂(L¹)(OAc)₂](OAc) (Co2L1, HL¹ = 2,6-bis((bis(pyridin-2-ylmethyl)amino)methyl)-4-methoxyphenol), which accelerates the visible-light-driven conversion of CO₂ to CO in acetonitrile/water (4/1, v/v) nearly 40% more than that for the previously reported [Co₂(L²)(OAc)₂](OAc) (Co2L2, HL² = 2, 6-bis((bis(pyridin-2-ylmethyl)amino)methyl)-4-(tert-butyl)phenol) by our research group. It has an excellent CO selectivity of 98%, and the TON_CO is as high as 5920. Experimental results and DFT calculations showed that the enhanced catalytic performance of Co2L1 is due to the electron-donating effect of a methoxy group (-OCH₃) in Co2L1 compared to a tertiary butyl group (-C(CH₃)₃) in Co2L2, which reduces the energy barrier of the rate-limiting CO₂ coordination step in the visible-light-driven CO₂ reduction process.

Highly Efficient Visible-Light-Driven CO2-to-CO Conversion by Coordinatively Unsaturated Co-Salen Complexes in a Water-Containing System

The development of cost-effective catalysts for CO₂ reduction is highly desired but remains a significant challenge. The unsaturated coordination metal center in a catalyst is favorable for the process of catalytic CO₂ reduction. In this paper, two asymmetric salen ligands were used to synthesize two coordinatively unsaturated Co-salen complexes. The two Co-salen complexes exhibit an unsaturated coordination pattern and display high activity and CO selectivity for visible-light-driven CO₂ reduction in a water-containing system. The photocatalytic performance of 2 is higher than that of 1 because the reduction potential of the catalytic Co^II center and the energy barrier of the catalytic transition states of 2 are lower than those of 1, with turnover numbers (TON_CO), turnover frequencies (TOF), and CO selectivity values of 8640, 0.24 s^-1, and 97% for 2, respectively. The photocatalytic reduction of CO₂ to CO for 2 is well supported by control experiments and density functional theory (DFT) calculations.

GWAS in Mice Maps Susceptibility to HIV-Associated Nephropathy to the Ssbp2 Locus

BACKGROUND

To gain insight into the pathogenesis of collapsing glomerulopathy, a rare form of FSGS that often arises in the setting of viral infections, we performed a genome-wide association study (GWAS) among inbred mouse strains using a murine model of HIV-1 associated nephropathy (HIVAN).

METHODS

We first generated F1 hybrids between HIV-1 transgenic mice on the FVB/NJ background and 20 inbred laboratory strains. Analysis of histology, BUN, and urinary NGAL demonstrated marked phenotypic variation among the transgenic F1 hybrids, providing strong evidence for host genetic factors in the predisposition to nephropathy. A GWAS in 365 transgenic F1 hybrids generated from these 20 inbred strains was performed.

RESULTS

We identified a genome-wide significant locus on chromosome 13-C3 and multiple additional suggestive loci. Crossannotation of the Chr. 13 locus, including single-cell transcriptomic analysis of wildtype and HIV-1 transgenic mouse kidneys, nominated Ssbp2 as the most likely candidate gene. Ssbp2 is highly expressed in podocytes, encodes a transcriptional cofactor that interacts with LDB1 and LMX1B, which are both previously implicated in FSGS. Consistent with these data, older Ssbp2 null mice spontaneously develop glomerulosclerosis, tubular casts, interstitial fibrosis, and inflammation, similar to the HIVAN mouse model.

CONCLUSIONS

These findings demonstrate the utility of GWAS in mice to uncover host genetic factors for rare kidney traits and suggest Ssbp2 as susceptibility gene for HIVAN, potentially acting via the LDB1-LMX1B transcriptional network.

Role of secreted protein acidic in hematogenous metastasis of gastric cancer

OBJECTIVE

To investigate tumor microenvironment of metastasis (TMEM) and the expression of SPARC (secreted protein acidic and rich in cysteine) in gastric cancer, and their relationships with hematogenous metastasis.

PATIENTS AND METHODS

Twenty-six pairs of cases with gastric cancer were enrolled, in which there were 26 cases with distant organ metastases and 26 cases of gastric cancer without organ metastases as controls. TMEM (by double-stained immunohistochemistry) and the expression of SPARC were determined in twenty-six pairs of cases. In addition, we selected 48 patients to detect the expression of SPARC, VEGF (vascular endothelial growth factor), and evaluated TAMs (tumor associated macrophages), MVD (the microvessel density), MPI (microvessel pericyte coverage index), and TMEM in gastric cancer tissues by immunohistochemistry.

RESULTS

TMEM count was significantly higher in the metastatic gastric cancer tissues than that in non-metastatic cancer tissues in a case-control study (p<0.01). On the contrary, SPARC expression was lower in the metastatic gastric cancer tissues than that in non-metastatic cancer tissues. TMEM count, TAMs, and MVD were significantly correlated with invasion depth, histological type and TNM stage (p<0.05 or p<0.01). Expression of SPARC and VEGF were significantly correlated with tumor histological types, invasion depth, differentiation and lymph node metastasis of patients (p<0.05). SPARC and VEGF expression in stromal cells of gastric cancer tissues were significantly correlated with TAMs, MVD and MPI (p<0.05). In addition, SPARC expression was significantly inversely correlated with VEGF expression in gastric cancer tissues (p<0.05).

CONCLUSIONS

TMEM was detected in initial gastric cancer resection and closely correlated with hematogenous metastasis. Furthermore, SPARC may be involved in gastric cancer metastasis by effecting on tumor microenvironment.

ABCB1/MDR1 gene polymorphism and colorectal cancer risk: a meta-analysis of case-control studies

AIM

ABCB1/MDR1 protein is found in high concentrations on the apical surfaces of colonic epithelial cells. It acts as an efflux pump by transporting toxic endogenous substances, drugs and xenobiotics out of cells. Polymorphisms in the ABCB1/MDR1 gene may either change expression of the ABCB1/MDR1 protein or alter its function, suggesting its possible association with colorectal cancer. Several studies have reported a relationship between ABCB1 gene polymorphisms and colorectal cancer risk, but no consistent conclusion has been reached. We therefore conducted a meta-analysis to identify any association between the ABCB1 gene and CRC risk.

METHOD

PubMed, Embase, Google Scholar, Cbmdisc and CNKI were searched for studies on the relationship of ABCB1/MDR1 gene SNPs and the incidence of colorectal cancer. Eligible articles were included for data extraction. The main outcome was the frequency of ABCB1/MDR1 gene SNPs among cases and controls. Comparison of the distribution of SNPs was performed mainly using Review Manager 5.0.

RESULTS

Ten, four and two trials were identified that focussed on the ABCB1 gene SNPs rs1045642, rs2032582 and rs3789243, respectively. A total of 3175 cases and 3715 controls were included. The meta-analysis, stratified by ethnicity or population source, indicated no association between the ABCB1 gene rs1045642 polymorphism and colorectal cancer risk. However, when the study by Bae et al. was removed from the analysis, there was some evidence to indicate a higher T-allele frequency in Asian colorectal cancer patients (OR = 1.30, 95% CI: 1.02-1.67, P = 0.03). Neither ABCB1 rs2032582 nor ABCB1 rs3789243 indicated an association with colorectal cancer risk. An increased frequency only of the wild-type combined allele (rs2032582G/rs1045642C) was found in Caucasian patients (OR = 1.22, 95% CI: 1.03-1.44, P = 0.02).

CONCLUSION

There is some evidence to indicate an association between ABCB1 rs1045642T and colorectal cancer risk in Asians. Compared with the ABCB1 gene SNPs rs1045642, rs2032582 or rs3789243 alone, combined haplotypes of several SNPs might be a better marker to determine the genetic influence on the susceptibility to colorectal cancer among Caucasians.

ABCB1/MDR1 gene polymorphism and colorectal cancer risk: a meta-analysis of case-control studies

AIM

ABCB1/MDR1 protein is found in high concentrations on the apical surfaces of colonic epithelial cells. It acts as an efflux pump by transporting toxic endogenous substances, drugs and xenobiotics out of cells. Polymorphisms in the ABCB1/MDR1 gene may either change expression of the ABCB1/MDR1 protein or alter its function, suggesting its possible association with colorectal cancer. Several studies have reported a relationship between ABCB1 gene polymorphisms and colorectal cancer risk, but no consistent conclusion has been reached. We therefore conducted a meta-analysis to identify any association between the ABCB1 gene and CRC risk.

METHOD

PubMed, Embase, Google Scholar, Cbmdisc and CNKI were searched for studies on the relationship of ABCB1/MDR1 gene SNPs and the incidence of colorectal cancer. Eligible articles were included for data extraction. The main outcome was the frequency of ABCB1/MDR1 gene SNPs among cases and controls. Comparison of the distribution of SNPs was performed mainly using Review Manager 5.0.

RESULTS

Ten, four and two trials were identified that focussed on the ABCB1 gene SNPs rs1045642, rs2032582 and rs3789243, respectively. A total of 3175 cases and 3715 controls were included. The meta-analysis, stratified by ethnicity or population source, indicated no association between the ABCB1 gene rs1045642 polymorphism and colorectal cancer risk. However, when the study by Bae et al. was removed from the analysis, there was some evidence to indicate a higher T-allele frequency in Asian colorectal cancer patients (OR = 1.30, 95% CI: 1.02-1.67, P = 0.03). Neither ABCB1 rs2032582 nor ABCB1 rs3789243 indicated an association with colorectal cancer risk. An increased frequency only of the wild-type combined allele (rs2032582G/rs1045642C) was found in Caucasian patients (OR = 1.22, 95% CI: 1.03-1.44, P = 0.02).

CONCLUSION

There is some evidence to indicate an association between ABCB1 rs1045642T and colorectal cancer risk in Asians. Compared with the ABCB1 gene SNPs rs1045642, rs2032582 or rs3789243 alone, combined haplotypes of several SNPs might be a better marker to determine the genetic influence on the susceptibility to colorectal cancer among Caucasians.

Sonographic examination of uteroplacental separation during the third stage of labor

OBJECTIVES

To characterize patterns of uteroplacental separation during the third stage of labor, and to investigate their association with previous history of Cesarean section (CS), delays in placental separation and blood loss.

METHODS

In this cohort observational study, continuous ultrasound imaging of uteroplacental separation was performed during the third stage of labor in 78 vaginal deliveries. All women were primiparous and were divided into two groups: those with a previous vaginal delivery (n = 62) and those who had undergone CS (n = 16).

RESULTS

Three patterns of separation were observed: 'down-up' (n = 64), 'up-down' (n = 12) and 'bipolar' (n = 2). Bipolar separation was observed only with fundal placentae. Up-down separation was significantly associated with a history of CS (P < 0.001; odds ratio 14.0; 95% CI, 3.4-57.4) and a longer second stage of labor (P = 0.02).

CONCLUSIONS

In most cases, uteroplacental separation begins at the lower placental pole and proceeds upwards. Women with a history of CS have a higher rate of up-down separation, possibly owing to impaired lower uterine segment contractility.

Estrogen and "exercise" have a synergistic effect in preventing bone loss in the lumbar vertebra and femoral neck of the ovariectomized rat

This study was designed to study the individual or combined effects of estrogen and bipedal stance "exercise" on the lumbar vertebral body (LVB) and femoral neck (FN). At 6 months of age, six rats were sacrificed as baseline controls and all the others were either bilateral sham-ovariectomized or ovariectomized (OVX). Groups of OVX rats were housed in normal height cage (NC, 28 cm) or raised height cages (RC, 33 cm) and received biweekly s.c. injections of 10 microg/kg 17 beta estradiol (E2) or vehicle for 4 and 8 weeks. Histomorphometric measurements were performed on the undecalcified mid-transverse sections of the 4th LVB and FN. Ovariectomy alone induced cancellous bone loss by 21% and 39% in the LVB and FN, respectively; intracortical porosity area of the FN increased by 108% while total bone area did not change significantly because of the periosteal expansion following OVX. E2 alone partially prevented cancellous bone loss in the LVB and FN and prevented increased intracortical porosity area in the FN by reducing eroded surface and activation frequency. RC alone partially prevented the decrease of cancellous bone in the LVB and FN by reducing the bone-eroded surface but increased wall width. E2 plus RC completely preserved cancellous bone by having an additive effect on reducing eroded surface and activation frequency. RC helped to partially prevent decreased periosteal bone formation after estrogen administration. In conclusion, apart from inducing cancellous bone loss in the LVB and FN, OVX also increased intracortical remodeling in the FN. Estrogen prevented the overall activation of remodeling space induced by OVX. Apart from having similar effects as estrogen on remodeling space, RC induced positive bone balance within each remodeling unit. Combination treatment increased total bone mass beyond that of sham-control level by having an additive effect on lowering bone remodeling and increasing wall in both the LVB and FN.

Bipedal stance exercise and prostaglandin E2 (PGE2) and its synergistic effect in increasing bone mass and in lowering the PGE2 dose required to prevent ovariectomized-induced cancellous bone loss in aged rats

Previous reports have shown that bone loss was partially prevented by bipedal stance "exercise" following ovariectomy (ovx), and it was well documented that prostaglandin E2 (PGE(2)) had an anabolic effect on the rat skeleton. The aim of this study was to determine whether lower doses of PGE(2) could prevent ovx-induced cancellous bone loss with the combination of bipedal stance exercise. Seventy-eight 10-month-old female Sprague-Dawley rats were either ovariectomized or sham-operated on day 0 and then treated with PGE(2) (0, 0.3, or 1 mg/kg per day) and/or housed in normal height cages (NC, 28 cm) or raised cages (RC, 33 cm) for 8 weeks. Bone histomorphometry was performed on the double-fluorescent-labeled proximal tibial metaphysis. In sham rats, 1 mg/kg PGE(2) + RC had synergistic effects in increasing trabecular bone area, width, and number by stimulating mineral apposition rate and bone formation rate. As expected, ovx induced cancellous bone loss, accompanied by elevated activation frequency. Without RC, PGE(2) monotherapy prevented ovx-induced bone loss at the 1 mg/kg per day dose, whereas this prevention effect was observed at the 0.3 mg/kg per day dose when combined with RC. Similar to their effects in sham rats, PGE(2) and RC had synergistic effects in augmenting cancellous bone mass and architecture and maintaining the elevated bone formation but depressing bone resorption and activation frequency. We conclude that bipedal stance exercise lowers the PGE(2) dose required to prevent ovx-induced cancellous bone loss in the proximal tibial metaphysis in aged rats.

[The influences of crystallized compositions in the porcelain on bonding strength of titanium to porcelain]

OBJECTIVE

Sufficient porcelain-titanium bond is a vital factor determining the clinical performance of titanium-porcelain restorations. The purpose of this study was to investigate the effects of self-preparation La-porcelain composition on the porcelain-titanium bonding strength and to compare with the Vita Titankeramik.

METHODS

The present study examines 5 different recipes of porcelain by weight%: SiO2, 12%-17%; LaO2, 7%-10%; Al2O3, 9%-14%; B2O3, 23%-31%; CaO, 6%-8%; K2O, 2%-3%; SrO, 2%-4%; Na2O, 1%-3%; SnO2, 8%-10%; ZrO2, 3%-5%; TiO2, 6%-8%. Specimens were tested in push type shear with a universal testing machine. Scanning electron microscopy (SEM) and electron probe microanalyzer (EPMA) were employed to reveal the microstructures and diffusion of elements in the interfacial regions between the porcelain coating and titanium to the bond strength when fired at 800 degrees C.

RESULTS

The ratios of crystallized compositions had significant influences on the porcelain-titanium bond strength (P < 0.05). La-porcelain had the highest shear bond strength (37.76 MPa). The shear bond strength of the Vita Titankeramik to titanium was 20.18 MPa. The results of SEM revealed integrity of porcelain-titanium joints in La-porcelain and a greater amount of porosity in the interface of Vita Titankeramik to titanium. EPMA analysis demonstrated the aggregation of Si and Sn in the interfacial regions and their diffusion into the titanium.

CONCLUSION

Chemical compositions of porcelain and ratios of crystallized compositions play the important role in the titanium porcelain bond. La-porcelain had the highest shear bond strength and good porcelain-titanium joints. La-porcelain is a new-style low fusing porcelain/titanium system.

[A study on the bond interface between low-fusing dental porcelain and pure titanium]

OBJECTIVE

To evaluate the bond interface between low fusing dental porcelain and pure titanium by observing the topography and detecting the ionic diffusion in the interface area.

METHODS

The low fusing-porcelain La-porcelain produced by the authors or Vita Titankeramik porcelain was fused to the surfaces of pure titanium. The topography of the interface between pure titanium and porcelain, and the structure of experimental materials were observed with SEM. The state of ionic diffusion in the interface area was investigated with EPMA.

RESULTS

Excellent permeation and diffusion of La-porcelain were observed on the surfaces of pure titanium. The diffusion of ions of stannum and silicon was discovered in the interface area. The microstructure of La-porcelain to pure titanium bond interface was finer than that of Vita Titankeramik porcelain.

CONCLUSION

Excellent bond can be produced in the interface between La-porcelain and pure titanium. The bonding mechanism may involve mechanical bond and chemical bond. The ionic diffusion of stannum plays an important role in the bonding of porcelain to pure titanium.

[A two-years clinical observation of all-ceramic restorations using Vita In-Ceram glass-infiltrated ceramic]

OBJECTIVE

This paper observed the clinical effect of Vita In-Ceram glass-infiltrated ceramic restorations.

METHOD

A total of 194 restorations (124 maxillary and 70 mandibular prostheses) made with Vita In-Ceram glass-infiltrated ceramic were examined in 45 patients. There were 165 anterior tooth crowns, 21 posterior tooth crowns, and 8 FPDs. Surface, color, anatomic form, and marginal integrity of restorations were assessed at 3 months, 6 months, 1 year and 2 years after cementation with the California Dental Association (CDA) quality assessment evaluation system.

RESULTS

It showed that the marginal fitness, color stability and strength of crowns were considered to be satisfactory. Only 0.01% (two crowns) were not acceptable. Two FPDs were not acceptable at 6-month visit, however, the anterior FPDs were considered to be satisfactory.

CONCLUSION

It is possible to constructexcellent all-ceramic prostheses with the Vita In-Ceram glass-infiltrated ceramic system.

[Metastasis to the penis from carcinoma of the rectum. A clinical case]

Penile metastases are extremely uncommon, with less than 300 reported cases. The primary sites of the responsible carcinoma have been bladder, rectum, prostate, kidney, testis, lung, nasopharynx and melanoma in that order. We report a case confirming the same data: no therapy has been shown to be helpful, the prognosis is very poor, with an average survival of less than one year. On the other hand we pointed out the importance of CT scan as a diagnostic tool for assessing the spread of neoplasm.

Complex segregation analysis of autism

A complex segregation analysis of autism in 185 Utah families was carried out using the mixed model. The 209 affected individuals in these families represent nearly complete ascertainment of the autistic cases born in Utah between 1965 and 1984. The sibling recurrence risk for autism was 4.5% (95% confidence limits 2.8%-6.2%). Likelihoods were maximized for major-gene models, a polygenic model, a sibling-effect model, and a mixed model consisting of major-gene and shared-sibling effects. The analysis provided no evidence for major-locus inheritance of autism. Subdivision of the sample according to the probands' IQ levels showed that sibling recurrence risk did not vary consistently with IQ level. A segregation analysis of families in which the proband had an IQ less than 50 also failed to provide evidence for a major locus. However, because of the etiologic heterogeneity of this disorder, genetic analysis of other meaningful subsets of families could prove informative.

The UCLA-University of Utah epidemiologic survey of autism: the etiologic role of rare diseases

Twelve rare diseases known to cause CNS pathology were found in 26 (11%) of 233 autistic probands identified during a recent epidemiologic survey of Utah. These 26 probands had significantly lower mean IQs than the remaining patients (43 versus 60) but similar sex distribution and prevalence of abnormal EEGs and seizures. The rarity and diversity of these 12 diseases make it highly unlikely that they randomly occurred with autism. Their presence in this epidemiologic survey is the most compelling evidence to date to support the hypothesis that different diseases producing different types of CNS pathology can play an etiologic role in autism.

The UCLA-University of Utah epidemiologic survey of autism: prenatal, perinatal, and postnatal factors

In a recent epidemiologic survey conducted in Utah, 241 autistic patients (DSM-III criteria) were found. Medical records of 233 autistics were surveyed for the presence of 36 potentially pathologic prenatal, perinatal, and postnatal factors. These results were compared with those of an identical survey of 62 of their nonautistic siblings, with the results of four previously published surveys, and with normative data. No potentially pathologic factor or group of factors occurred significantly more frequently among the autistic patients. Also, previous observations of significant differences in the occurrence of certain factors in the histories single vs multiple siblings with autism were not confirmed, with the exception of increased viral-type illness during gestation in single-incidence cases. Thus, the etiology of the brain pathology that characteristically disrupts normal development and produces the syndrome of autism remains obscure. Other data from the epidemiologic survey, however, suggest that the role of genetic factors needs to be explored further.

The UCLA-University of Utah epidemiologic survey of autism: genealogical analysis of familial aggregation

To assess familial aggregation of autism, 86 autistic subjects were linked to the Utah Genealogical Database. Kinship coefficients were estimated for all possible pairs of autistic subjects and then averaged. Fifty replicate sets of matched control subjects (86 members in each set) were drawn randomly from the database, and the average kinship coefficient was computed for all possible pairs of individuals in each set. The average kinship coefficient for the autistic subjects was approximately 1/1,000, while the average kinship coefficients for the 50 control groups ranged from 4/100,000 to 1.6./10,000. These results indicate a strong tendency for autism to cluster in families. When kinship was analyzed by specific degrees of relationship, it was shown that the familial aggregation of autism is confined exclusively to sib pairs and does not extend to more remote degrees of relationship. This finding indicates that a single-gene model is unlikely to account for most cases of autism.

The UCLA-University of Utah epidemiologic survey of autism: recurrence risk estimates and genetic counseling

The authors recently reported, in this journal, an epidemiologic survey of autism in Utah. Twenty (9.7%) of the 207 families ascertained had more than one autistic child. Analyses of these data revealed that autism is 215 times more frequent among the siblings of autistic patients than in the general population. The overall recurrence risk estimate (the chance that each sibling born after an autistic child will develop autism) is 8.6%. If the first autistic child is a male the recurrence risk estimate is 7%, and if a female 14.5%. These new recurrence risk estimates should be made available to all individuals who have autistic children and are interested in family planning.

Psychometric assessment of first-degree relatives of 62 autistic probands in Utah

The Wechsler Intelligence Scales, Wide Range Achievement Test, and the Shipley-Hartford Test were administered to 122 parents and 153 siblings of 62 autistic probands in Utah. Scores were distributed as expected within the published normative ranges for each scale. Parents' scores correlated with those of their nonautistic children, but neither parents' nor siblings' scores correlated with the IQ level of the autistic probands. These results do not confirm prior reports from England and the United States of a high rate of cognitive and learning problems in the siblings of autistic individuals, nor the aggregation of such problems in the siblings of probands with high or low levels of cognitive function.

The UCLA-University of Utah epidemiologic survey of autism: prevalence

The authors conducted an epidemiologic survey in Utah using a four-level ascertainment system, blind current diagnostic assessments, and DSM-III criteria. Of 483 individuals ascertained, 241 were diagnosed as having autism. The best estimate for the prevalence rate was 4 per 10,000 population. Autism was not associated with parental education, occupation, racial origin, or religion. Sixty-six percent of the autistic subjects scored below 70 on standardized IQ tests, and females scored proportionately lower than males. Twenty (9.7%) of 207 families had more than one autistic sibling, which supports the authors' previous finding that there may be a familial subtype of autism.

Evidence for autosomal recessive inheritance in 46 families with multiple incidences of autism

The authors ascertained 46 families with multiple incidences of autism (41 with two and five with three autistic probands). Classical segregation analyses revealed a maximum likelihood estimate of the segregation ratio of p = 0.19 +/- 0.07. This is not significantly less than 0.25, the expected value for autosomal recessive inheritance. However, it is significantly less than 0.50, the expected value for autosomal dominant inheritance. The polygenic threshold model was tested and rejected over a full range of values of heritability and ascertainment probability for these families. These results are most consistent with the hypothesis of autosomal recessive inheritance in this subset of 46 families with multiple incidences of autism.

Concordance for the syndrome of autism in 40 pairs of afflicted twins

The UCLA Registry for Genetic Studies in Autism was established in 1980 to test the hypothesis that genetic factors may be etiologically significant in subsets of patients. To date 61 pairs of twins have enrolled and 40 meet research diagnostic criteria for autism. The authors found a concordance for autism in these 40 pairs of 95.7% in the monozygotic twins (22 of 23) and 23.5% in the dizygotic twins (four of 17).

Relationship between plasma pH and pancreatic HCO3- secretion at different intravenous secretin infusion rates

The relationship between pancreatic HCO3- secretion and plasma pH during acute systemic acid-base changes was investigated in 6 anesthetized, artificially ventilated pigs (20-25 kg) at 2 different, i.v. secretion infusion rates. At 0.45 C.U./kg b. wt. h-1 secretin infusion and plasma pH 7.40 +/- 0.01 pancreatic HCO3- secretion averaged 61+/- 12 mumol/min. Stepwise lowering of plasma pH through i.v. infusion of HCl and CO2 administration to inspired air proportionately reduced secretion rate; estimated zero HCO3- secretion occurring at plasma pH 7.01. Subsequent i.v. secretin infusion at 2.70 C.U./kg b. wt. h-1 increased HCO3- secretion to 249 +/- 42 mumol/min at plasma pH 7.33 + 0.04; stepwise lowering of plasma pH proportionately reduced HCO3- secretion to estimated zero at plasma pH 6.71. A reduction of plasma pH by 0.1 pH unit reduced HCO3- secretion during low and high rate of i.v. secretin infusion by 18 +/- 3 mumol/min and 35 +/- 8 mumol/min, respectively. Secretin infusion rate did not affect pancreatic chloride excretion. These findings support the view that secretin increases HCO3- secretion, and hence proton transport to the interstitial fluid, by augmenting the proton motive force developed by HCO3- secreting cells.

Influence of click sound pressure direction on brain stem responses in children

Brain stem auditory responses were evoked by stimulation with condensation (C) and rarefaction (R) clicks separately. The latencies of the first five waves of the response were compared in response to the two sound pressure directions. Responses to R clicks were significantly shorter than responses to C clicks for wave 4, in the absence of consistent response differences in the other waves.

Effect of plasma H+-ion concentration on pancreatic HCO-3 secretion

The relationship between the rate of pancreatic HCO-3 secretion and plasma H+-ion concentration was investigated in 15 pentothal anesthetized, secretin infused pigs (1.8 C.U./kg b.w. h-1, intravenously) during acute metabolic and respiratory acid-base disturbances. Pancreatic HCO-3 secretion increasd to 196 +/- 10% of control during alkalosis and fell to 41 +/- 4% of control during acidosis. Partial metabolic compensation of respiratory acidosis restored HCO-3 secretion to 87 +/- 6% of control. A proportional relationship was found between HCO-3 secretion and plasma pH. Different, proportional relationships were found between HCO-3 secretion and plasma HCO-3 concentration during metabolic and respiratory acid-base changes. HCO-3 secretion was independent of H+-ion concentration in pancreatic juice. Plasma H+-ion concentration, therefore, seems to determine the rate of pancreatic HCO-3 secretion. This finding supports the hypothesis that a proton pump is responsible for pancreatic HCO-3 secretion.

Esterification of cholesterol in human small intestine: the importance of acyl-CoA:cholesterol acyltransferase

Human intestinal mucosa contains acyl-CoA:cholesterol acyltransferase activity. The enzyme has been studied by using oleylcarnitine, CoA and carnitine palmitoyltransferase as an oleyl-CoA regenerating system. The enzyme was found in the particulate fraction of the cells, it had a pH optimum between 7.2 and 8.2, and was inhibited by taurocholate. The specific enzymic activity in biopsies from intestinal mucosa of normal men was found to be 3.6 +/- 1.37 nmol cholesteryl ester formed mg protein-1 h-1, an activity which can account for all cholesteryl esters in intestinal lymph. Low enzymic activity was found in biopsies from patients with small intestinal disorders. Two pancreatectomized patients had values within the normal range.