scRNA-seq reveals that origin recognition complex subunit 6 regulates mouse spermatogonial cell proliferation and apoptosis via activation of Wnt/β-catenin signaling

ABSTRACT

The regulation of spermatogonial proliferation and apoptosis is of great significance for maintaining spermatogenesis. The single-cell RNA sequencing (scRNA-seq) analysis of the testis was performed to identify genes upregulated in spermatogonia. Using scRNA-seq analysis, we identified the spermatogonia upregulated gene origin recognition complex subunit 6 (Orc6), which is involved in DNA replication and cell cycle regulation; its protein expression in the human and mouse testis was detected by western blot and immunofluorescence. To explore the potential function of Orc6 in spermatogonia, the C18-4 cell line was transfected with control or Orc6 siRNA. Subsequently, 5-ethynyl-2-deoxyuridine (EdU) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays, flow cytometry, and western blot were used to evaluate its effects on proliferation and apoptosis. It was revealed that ORC6 could promote proliferation and inhibit apoptosis of C18-4 cells. Bulk RNA sequencing and bioinformatics analysis indicated that Orc6 was involved in the activation of wingless/integrated (Wnt)/ β-catenin signaling. Western blot revealed that the expression of β-catenin protein and its phosphorylation (Ser675) were significantly decreased when silencing the expression of ORC6. Our findings indicated that Orc6 was upregulated in spermatogonia, whereby it regulated proliferation and apoptosis by activating Wnt/β-catenin signaling.

First report of Alternaria alternata causing leaf yellow spot on Heteropanax fragrans in China

Heteropanax fragrans (Roxb.) Seem is a common garden landscape tree in China. In December 2020, a leaf disease on H. fragrans was observed in a 2 ha field in Zhanjiang (20.85° N, 109.28° E), Guangdong province, China. Early symptoms were small yellow spots on leaves. Later, the spots gradually expanded and turned into necrotic tissues with a clear yellow halo and a white center. The disease incidence on plants was 100%. Twenty diseased leaves were collected from the field. The margin of the diseased tissues was cut into 2 mm × 2 mm pieces, surface disinfected with 75% ethanol and 2% sodium hypochlorite for 30 and 60 s, respectively, and rinsed thrice with sterile water before isolation. The tissues were plated onto potato dextrose agar (PDA) medium and incubated at 28 ℃. After 2-day incubation, grayish fungal colonies appeared on the PDA, then pure cultures were produced by transferring hyphal tips to new PDA plates. Single-spore isolation method was used to recover pure cultures for three isolates (HFA-1, HFA-2, and HFA-3). The colonies first produced a light-grayish aerial mycelia, which turned dark grayish upon maturity. Conidiophores were branched. Conidia numbered from two to four in chains, were dark brown, ovoid, or ellipsoid and mostly beakless; had 1-4 transverse and 0-3 longitudinal septa; measured within 7.2-17.8 (average = 10.2) × 2.5-7.5 (average = 4.3) µm (n = 30). Molecular identification was performed using the colony polymerase chain reaction method with MightyAmp DNA Polymerase (Takara-Bio, Dalian, China) (Lu et al. 2012) to amplify the large subunit (LSU), internal transcribed spacer (ITS) region, translation elongation factor (TEF) , and Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) with NL1/LR3, ITS1/ITS4, EF-1α-F/EF-1α-R, and GDF1/GDR1 (Walther et al. 2013;Woudenberg et al. 2015; Nishikawa and Nakashima. 2020). Amplicons of the isolates were sequenced and submitted to GenBank (LSU, ON088978-ON088980; ITS, MW629797, ON417005 and ON417006; TEF, MW654167, ON497264,and ON497265;GAPDH, MW654166, ON497262,and ON497263). The obtained sequences were 100% identical with those of Alternaria alternata strain CBS 102600 upon BLAST analysis . The sequences were also concatenated for phylogenetic analysis by maximum likelihood. The isolates clustered with A. alternata (CBS 102600, CBS 102598, CBS 118814, CBS 918.96,CBS 106.24, CBS 119543, CBS 916.96). The fungus associated with leaf yellow spot on H. fragrans was thus identified as A. alternata. Pathogenicity tests were conducted in a greenhouse at 24 ℃-30 ℃ with 80% relative humidity. Individual plants were grown in pots (n = 5, 1 month old). The unwounded leaflets were inoculated with 5 mm-diameter mycelial plugs of the isolates or agar plugs (as control). The test was performed thrice. Disease symptoms were found on the leaves after 7 days, whereas the controls remained healthy. The pathogen was re-isolated from infected leaves and phenotypically identical to the original isolates to fulfill Koch's postulates. To our knowledge, this report is the first one on A. alternata causing leaf yellow spot on H. fragrans. Thus, this work provides an important reference for the control of this disease in the future.

First Report of Fusarium proliferatum Associated with Leaf Yellow on Alternanthera philoxeroides in China

Alternanthera philoxeroides (Mart.) Griseb is a highly invasive weed commonly found in rice fields in China. In May 2021, leaf yellowing was observed on this weed (about 10 ha) in Zhanjiang (21°19'N, 110°20'E), Guangdong Province, China. Disease incidence was approximately 20% (n = 100 investigated plants). Ten yellow leaves from 10 plants were sampled, surface-sterilized with 75% ethanol for 30 s, followed by 2% NaClO for 5 min. The leaves were rinsed three times in sterile distilled water and four sections of each leaf were placed onto potato dextrose agar (PDA). Pure cultures were obtained by transferring hyphal tips to new PDA plates. Twenty-two isolates of Fusarium ssp. (69% of the isolates) were obtained from 55% of the leaf samples. Three representative single-spore isolates (APF-1, APF-2, and APF-3) were used for further study. Colonies were white to pink on PDA. Conidiogenous cells were monophialidic or polyphialidic. Macroconidia were slightly curved, tapering apically with three to five septa, and measured from 32.5-55.8 μm × 2.5-5.1 μm in size (n=50). The morphological features of these fungi were noted to be in line with those of Fusarium proliferatum (Leslie and Summerell, 2006). For molecular identification, a colony PCR method (Lu et al. 2012) was used to amplify the internal transcribed spacer (ITS) and portions of elongation factor 1-α (EF1-α), RNA polymerase II largest subunit (RPB1), and RNA polymerase II second largest subunit (RPB2) genes using primers ITS1/ITS4, EF1-728F/EF1-986R, RPB1-R8/RPB1-F5, and RPB2-7CF/fRPB2-11aR, respectively (O'Donnell et al. 1998; O'Donnell et al. 2010). The sequences were submitted to GenBank under accession numbers MZ026797-MZ026799 (ITS) and MZ032209-MZ032217 (RPB1, RPB2, EF1-α). The sequences of the three isolates were 100% identical (ITS, 537/537 bp; RPB1, 1606/1606 bp; RPB2, 770/770 bp and EF1-α, 683/683 bp) with those of F. proliferatum (accession nos. MT378328, MN193921, MH582196, and MH582344) through BLAST analysis. Analysis of the sequences revealed a 99.87 - 100% identity with the isolates of the F. proliferatum (F. fujikuroi species complex, Asian clade) by polyphasic identification using the FUSARIUM-ID database (Yilmaz et al. 2021). The sequences were also concatenated for phylogenetic analysis by the maximum likelihood method. The isolates clustered with F. proliferatum. Pathogenicity was tested through in vivo experiments. The inoculated and control plants (n = 5, 30 days old) were sprayed with a spore suspension (1 × 105 per mL) of the three isolates individually and sterile distilled water, respectively, until run-off (Feng and Li. 2019). The test was performed three times. The plants were grown in pots in a greenhouse at 25 °C to 28 °C, with relative humidity of approximately 80%. Yellowing was observed on the inoculated plants after 7 days, while the control plants remained healthy. The pathogen re-isolated from all the inoculated plants was identical to the inoculated isolates in terms of morphology and ITS sequences. No fungi were isolated from the control plants. To the best of our knowledge, this study is the first to report F. proliferatum causing yellow symptoms on A. philoxeroides. The fungus has some potential biological control properties, but its host range needs to be further determined.

Pseudocercospora rhododendricola Causing Leaf dark Spot on Rhododendron pulchrum by the first phylogenetic analyses

Rhododendron pulchrum Sweet is a famous ornamental flower in China. In December 2020, a leaf spot disease was observed on cv. Maojuan in Zhanjiang (21.17 N, 110.18 E), Guangdong, China. The spots were irregular and distributed on both sides of the main vein. They were dark to black, and their borders were obvious. The coalescence of the spots eventually led to leaf wilt. The disease incidence was 100% (n = 100, about 50 ha ). Thirty infected leaves were collected from the field, and the margin of the diseased tissues was cut into 2 mm × 2 mm pieces. Samples were surface disinfected with 75% ethanol and 2% sodium hypochlorite for 30 and 60 s, respectively. They were rinsed thrice with sterile water before isolation. The tissues were plated on potato dextrose agar (PDA) medium and incubated at 28 ℃. After 5 days, fungal colonies appeared on the PDA. Pure cultures were produced by transferring hyphal tips to new PDA plates. Three isolates (RSP-1, RSP-2, and RSP-3) were obtained and the colonies of isolates were preserved in glycerol (15%) at -80 °C deposited at the Museum of Guangdong Ocean University. The morphology of these three isolates was consistent, and their sequences showed 100% homology according to ITS, TEF1, and ACT analysis results. The colonies grew to approximately 5 cm in diameter after 10 days. They showed olive green with off-white aerial mycelia. Stromata and conidia were observed on leaf lesions. Stromata were olivaceous brown. Conidia were solitary, cylindrical to narrowly obclavate, mildly curved, obtuse to rounded at the apex, and 1- to 3-septate; they had dimensions of 20 to 60 × 2.0 to 3.0 μm (n = 30). These morphological characteristics were not different from the description of Pseudocercospora rhododendricola (J.M. Yen) Deighton (Liu et al. 1998). For molecular identification, the colony PCR method with MightyAmp DNA Polymerase (Takara-Bio, Dalian, China) (Lu et al. 2012) was used to amplify the internal transcribed spacer (ITS), translation elongation factor 1-α gene (TEF1), and actin (ACT) loci of the isolates using primer pairs ITS4/ITS5, EF1/EF2, and ACT-512F/ACT-783R, respectively (White et al., 1990; O'Donnell et al. 1997). The sequences of the isolate RSP-1 were deposited in the GenBank (ITS, MW629798; TEF1, MW654168; and ACT, MW654170). BLAST analysis showed that the sequences of P. rhododendricola were submitted to GenBank for the first time by the author of this paper. A phylogenetic tree was generated based on the concatenated data of ITS, TEF1, and ACT sequences from GenBank by the Maximum Likelihood method. The isolates were closest to Pseudocercospora sp. CPC 14711 (Crous et al., 2013). Phylogenetic and morphological analyses identified the isolates as P. rhododendricola. Pathogenicity tests were conducted in a greenhouse at 24 °C-30 ℃ with 80% relative humidity. Healthy cv. Maojuan were grown in pots. Unwounded leaflets were inoculated with 5 mm-diameter mycelial plugs of the isolates or agar plugs (as control) (5 leaflets per plant, 3 plants, 2-month-old plants). The test was performed thrice. Disease symptoms were found on the leaves after 2 weeks, whereas the control plants remained healthy. The fungus was re-isolated from the infected leaves and confirmed as the same isolates by morphological and ITS analyses. P. rhododendricola was the cause of leaf spot of Rhododendron sp. from Singapore (Liu et al., 1998). For the first time, this pathogen was identified by combining phylogenetic and morphological analyses. The sequences in this study would be used as the reference sequences for further studies.

Single-cell analysis of developing and azoospermia human testicles reveals central role of Sertoli cells

Clinical efficacy of treatments against non-obstructive azoospermia (NOA), which affects 1% of men, are currently limited by the incomplete understanding of NOA pathogenesis and normal spermatogenic microenvironment. Here, we profile >80,000 human testicular single-cell transcriptomes from 10 healthy donors spanning the range from infant to adult and 7 NOA patients. We show that Sertoli cells, which form the scaffold in the testicular microenvironment, are severely damaged in NOA patients and identify the roadmap of Sertoli cell maturation. Notably, Sertoli cells of patients with congenital causes (Klinefelter syndrome and Y chromosome microdeletions) are mature, but exhibit abnormal immune responses, while the cells in idiopathic NOA (iNOA) are physiologically immature. Furthermore, we find that inhibition of Wnt signaling promotes the maturation of Sertoli cells from iNOA patients, allowing these cells to regain their ability to support germ cell survival. We provide a novel perspective on the development of diagnostic methods and therapeutic targets for NOA.

Non-obstructive azoospermia affects 1% of men. Here, authors perform single-cell transcriptomic analysis of human testicular cells from healthy donors and non-obstructive azoospermia patients and find that inhibition of Wnt signaling promotes the maturation of Sertoli cells from patients.

Efficacy of intrauterine perfusion of peripheral blood mononuclear cells (PBMC) for infertile women before embryo transfer: meta-analysis

This meta-analysis was intended to evaluate the effects of intrauterine perfusion of peripheral blood mononuclear cells (PBMC) on the pregnancy outcomes including clinical pregnancy rates, embryo implantation rates, live birth rates and miscarriage rates of infertile women who were undergoing in vitro fertilisation (IVF) treatment. By searching Pubmed, Embase database, five articles meeting the inclusion criteria were included, and 1173 women were enrolled (intrauterine PBMC group: n = 514; NO-PBMC group: n = 659). For the entire IVF/ICSI population and one or two embryo transfer failure patients, there was no significant difference in endometrial thickness, embryo implantation rates, live birth rates, and miscarriage rates between the PBMC group and NO-PBMC group. Although the clinical pregnancy rates of the PBMC group were higher than that of the NO-PBMC group, the confidence interval was close to the line of unity. As for the patients with three or more implantation failures, the clinical pregnancy rates, embryo implantation rates and live birth rates were much higher in the PBMC group than that of the NO-PBMC group. In summary, current evidence suggests that intrauterine perfusion of PBMC can significantly improve pregnancy outcomes in patients who have three or more implantation failures.Impact statementWhat is already known on this subject? An increasing number of studies have shown that immune cells play an important role in embryo transfer. There is no reliable evidence to confirm the clinical efficacy of intrauterine perfusion of PBMC.What do the results of this study add? The current evidence suggests that intrauterine perfusion of PBMC can significantly improve pregnancy outcomes in patients who have three or more implantation failures.What are the implications of these findings for clinical practice and/or further research? To the best of our knowledge, this meta-analysis is the first to evaluate the effect of intrauterine perfusion of PBMC on pregnancy outcomes before embryo transfer. Our study indicated that intrauterine perfusion of PBMC significantly increased clinical pregnancy rates, embryo implantation rates, and live birth rates in patients who failed more than three implants.

[Detection and analysis of FAM19A4 promoter methylation in cervical exfoliated cells]

Objective: To investigate the cinical value of FAM19A4promoter methylation in cervicalexfoliated cells for triage of cervical cancer. Methods: A total of 162 high-risk HPV-infected patients who were pathologically confirmed as different cervical lesions from August 2017 to December 2017 were collected in Guangdong Women and Children Hospital. Taqman probe-based quantitative PCR (qPCR) was used to detect the methylation of FAM19A4 promoterin different grades of cervical lesions, and the value of FAM19A4 methylation in predicting cervical HSIL and the above lesions was calculated by diagnostic test. Results: (1)The positive rates of FAM19A4 methylation in cervical exfoliated cells increased with the severity of cervical lesions, which were 7.69% (4/52) , 34.62% (9/26) , 55.56% (20/36) , 95.83% (46/48) in normal cervix/cervicitis, cervical LSIL, HSIL, and cervical cancer, respectively(P<0.05).(2)There was no significant difference in the detection rates of FAM19A4 methylation between different age groups, pathological types, clinical stage, tumor size and lymph node metastasis status (P>0.05). (3) The specificity and positive predictive value of FAM19A4 methylation in detecting cervical HSIL alone and ≥HSIL lesions were the optimal, with the AUC of 0.69 and 0.84, respectively. When combined with HPV16/18 genotyping, the sensitivity was significantly improved. Conclusions: The detection of FAM19A4 promoter methylation in cervical exfoliated cells has a high clinical value of discriminating ≥HSIL lesions; and the cotest of methylated FAM19A4 and HPV16/18 genotyping can identify ≥HSIL lesions more sensitively.

Excess of dietary montmorillonite impairs growth performance, liver function, and antioxidant capacity in starter pigs

Montmorillonite (MMT) is widely used as a mycotoxin adsorbent in animal feeds, but its safety remains unclear. This study was conducted to investigate the safety of MMT supplementation in diets fed to starter pigs. A total of 120 32-d-old piglets (initial weight, 8.0 ± 0.9 kg) were randomly allotted into dietary treatments with graded MMT levels (0 [FS 0], 0.5% [FS 0.5], 1.0% [FS 1.0], 2.5% [FS 2.5], and 5.0% [FS 5.0]) with 6 replicate pens per treatment and 4 pigs per pen. All diets were fed for 28 d. As the MMT level increased, ADG and G:F changed in a linear and quadratic manner, while ADFI was linearly decreased ( > 0.05). Compared with FS 0, ADG, ADFI, and G:F of pigs in FS 1.0 increased ( < 0.05). However, the ADFI in pigs of FS 5.0 was lower than that in pigs of FS 0 ( < 0.05). The relative liver weight activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) changed in a linear and quadratic manner ( < 0.05). Compared with FS 0, pigs in FS 2.5 and FS 5.0 had a greater serum ALT ( < 0.05), while AST activity significantly increased in pigs of FS 5.0 ( < 0.05). Dietary MMT supplementation decreased serum Mg content in a linear and quadratic manner ( < 0.05), while Zn and Cu contents were linearly decreased ( < 0.05). Serum Zn and Cu contents of pigs in FS 0.5, FS 2.5, and FS 5.0 groups were lower than those in the control. Pigs fed with 2.5% and 5% MMT showed hepatic histopathological changes, including swelling, granular and vesicular degeneration, and apparent vacuolar degeneration. In addition, the content of serum total antioxidant capacity (T-AOC) and activity of glutathione peroxidase (GSH-PX) decreased in a linear and quadratic manner ( < 0.05). Compared to the control, 5.0% MMT significantly increased piglets' serum malondialdehyde (MDA) concentration and decreased GSH-PX activity ( < 0.05). T-AOC concentration in the pigs fed 2.5% and 5.0% MMT was lower than that in the control group ( < 0.05). Serum superoxide dismutase (SOD) activity changed in a quadratic manner ( < 0.05). Piglets in FS 1.0 showed a higher SOD activity when compared with the control ( < 0.05). These results indicate that supplementation of MMT higher than 1.0% can negatively affect liver structure and serum mineral content, and 5.0% MMT supplementation would also decrease feed intake, aggravate liver damage, and reduce the antioxidant capacity of starter pigs. Therefore, excess supplementation of MMT is not safe in starter pigs.

Benzoic acid beneficially affects growth performance of weaned pigs which was associated with changes in gut bacterial populations, morphology indices and growth factor gene expression

This study was conducted to investigate the effects of benzoic acid (BA) on growth performance, intestinal development and intestinal barrier function in weaned pigs. Ninety weaned pigs were randomly assigned to one of three treatments: a basal diet (CON), the basal diet supplemented with 2000 mg/kg benzoic acid (BA1) and 5000 mg/kg benzoic acid (BA2). At the end of days 14 and 42, six pigs per treatment were randomly selected to collect plasma and intestinal samples. Results showed that BA supplementation not only improved final body weight, daily growth and feed conversion ratio from days 15 to 42 and days 1 to 42, but also decreased the activity of plasma diamine oxidase (day 42) and the pH values of jejunal contents (day 14) (p < 0.05). Ileal Bacillus populations (day 14) were increased by BA, while Escherichia coli counts in the ileum and caecum (day 42) were decreased (p < 0.05). Higher Lactobacillus counts occurred in the ileum (day 14, 42) of BA1-fed piglets as compared to CON and BA2-fed piglets (p < 0.05). In addition, BA supplementation increased the ratio of villus height to crypt depth (day 14, 42) and decreased the crypt depth (day 14) (p < 0.05). Growth-stimulating factors (insulin-like growth factor-1, day 42; insulin-like growth factor-1 receptor, day 14, 42) and tight junction protein (occludin, day 14, 42; zonula occludens-1, day 42)-related gene mRNA levels were upregulated in the jejunum of piglets fed BA diets (p < 0.05). In conclusion, this study provides the first evidence that BA has beneficial effects on intestinal development and intestinal barrier function of weaned pigs, which can partly explain why growth performance of pigs was improved by dietary BA supplementation.

Improved fluorimetric determination of dissolved aluminium by micelle-enhanced lumogallion complex in natural waters

A modification of the aluminium-lumogallion fluorescence measurement in the presence of the non-ionic surfactant Triton X-100 is presented. The detection limit for dissolved Al is 0.7 nM, with a relative standard deviation of 3.6% at an Al level of 5.0 nM. Compared with previously reported methods in the literature, the method described here is free from matrix effects and can be used for the determination of aluminium in fresh, estuarine and saline waters. The interferences from iron and fluoride were minimized by the addition of o-phenanthroline and Be2+, respectively. The analysis of NIST SRM 1643C and PRC standard 2430101 by the proposed method provides results consistent with the certified values. A successful inter-laboratory calibration exercise also demonstrates the merit of the proposed method for the determination of Al in environmental and marine sciences.

[Discriminant function based on serum analyte for diagnosis of primary hepatic cancer]

OBJECTIVE

The aim of this study was to diagnose primary hepatic cancer(PHC).

METHODS

Seven serum indexes of 92 serum samples consisting of 48 controls and 44 PHC were detected. Four discriminant functions based on seven serum indexes were obtained with computer SPSS statistic package.

RESULTS

The rate of coincidence, sensitivity, and specificity of the general discriminant functions were 86.96%, 77.27%, and 95.83% respectively; and that of the stepwise discriminant functions were 84.78%, 79.55%, and 89.59% respectively.

CONCLUSION

Usually PHC can be diagnosed by analyzing patients serum indexes with the discriminant functions.

Mitogenic phospholipase D activity is restricted to caveolin-enriched membrane microdomains

Phospholipase D (PLD) activity is elevated in response to the oncogenic stimulus of several signaling oncogenes. PLD activity is also elevated in response to peptide growth factors, indicating that PLD likely plays an important role in mitogenic signaling. Many proteins that mediate mitogenic signaling are localized in caveolin-enriched membrane microdomains (CEMMs). We report here that the elevated PLD activity in NIH 3T3 cells transformed by activated oncogenic forms of Src, Ras, and Raf is largely restricted to the CEMMs. Likewise, the PLD activity stimulated by epidermal growth factor is also restricted to the CEMMs. Although both PLD1 and PLD2 were found in CEMMs, neither was particularly enriched in the CEMMs of the transformed relative to the parental cells, indicating that it is the specific activity of PLD that is increased in the CEMMs. An apparent PLD substrate specificity in transformed cells for phosphatidylcholine lacking arachidonate acyl groups is also explained by the localization of activity in the CEMMs where [(3)H]arachidonate-labeled PC was excluded. These data indicate that mitogenic signals through PLD are initiated in CEMMs where many signaling molecules colocalize.

SPECT brain perfusion findings in mild or moderate traumatic brain injury

BACKGROUND

The purpose of this manuscript is to present the findings in the largest series of SPECT brain perfusion imaging reported to date for mild or moderate traumatic brain injury.

PATIENTS AND METHODS

This is a retrospective evaluation of 228 SPECT brain perfusion-imaging studies of patients who suffered mild or moderate traumatic brain injury with or without loss of consciousness (LOC). All patients had no past medical history of previous brain trauma, neurological, or psychiatric diseases, HIV, alcohol or drug abuse. The patient population included 135 males and 93 females. The ages ranged from 11-88 years (mean 40.8). The most common complaints were characteristic of the postconcussion syndrome: headaches 139/228 (61%); dizziness 61/228 (27%); and memory problems 63/228 (28%). LOC status was reported to be positive in 121/228 (53%), negative in 41/228 (18%), and unknown for 63/228 (28%).

RESULTS

Normal studies accounted for 52/228 (23%). For abnormal studies (176/228 or 77%) the findings were as follows: basal ganglia hypoperfusion 338 lesions (55.2%); frontal lobe hypoperfusion 146 (23.8%); temporal lobes hypoperfusion 80 (13%); parietal lobes hypoperfusion 20 (3.7%); insular and or occipital lobes hypoperfusion 28 (4.6%). Patients' symptoms correlated with the SPECT brain perfusion findings. The SPECT BPI studies in 122/228 (54%) were done early within 3 months of the date of the accident, and for the remainder, 106/228 (46%) over 3 months and less than 3 years from the date of the injury. In early imaging, 382 lesions were detected; in 92 patients (average 4.2 lesions per study) imaging after 3 months detected 230 lesions: in 84 patients (average 2.7 lesions per study).

CONCLUSIONS

Basal ganglia hypoperfusion is the most common abnormality following mild or moderate traumatic brain injury (p = 0.006), and is more common in patients complaining of memory problem (p = 0.0005) and dizziness (p = 0.003). Early imaging can detect more lesions than delayed imaging (p = 0.0011). SPECT brain perfusion abnormalities can occur in the absence of LOC.

SPECT brain perfusion abnormalities in mild or moderate traumatic brain injury

The purpose of this atlas is to present a review of the literature showing the advantages of SPECT brain perfusion imaging (BPI) in mild or moderate traumatic brain injury (TBI) over other morphologic imaging modalities such as x-ray CT or MRI. The authors also present the technical recommendations for SPECT brain perfusion currently practiced at their center. For the radiopharmaceutical of choice, a comparison between early and delayed images using Tc-99m HMPAO and Tc-99m ECD showed that Tc-99m HMPAO is more stable in the brain with no washout over time. Therefore, the authors feel that Tc-99m HMPAO is preferable to Tc-99m ECD. Recommendations regarding standardizing intravenous injection, the acquisition, processing parameters, and interpretation of scans using a ten grade color scale, and use of the cerebellum as the reference organ are presented. SPECT images of 228 patients (age range, 11 to 88; mean, 40.8 years) with mild or moderate TBI and no significant medical history that interfered with the results of the SPECT BP were reviewed. The etiology of the trauma was in the following order of frequency: motor vehicle accidents (45%) followed by blow to the head (36%) and a fall (19%). Frequency of the symptoms was headache (60.9%), memory problems (27.6%), dizziness (26.7%), and sleep disorders (8.7%). Comparison between patients imaged early (<3 months) versus those imaged delayed (>3 months) from the time of the accident, showed that early imaging detected more lesions (4.2 abnormal lesions per study compared to 2.7 in those imaged more than 3 months after the accident). Of 41 patients who had mild traumatic injury without loss of consciousness and had normal CT, 28 studies were abnormal. Focal areas of hypoperfusion were seen in 77% (176 patients, 612 lesions) of the group of 228 patients. The sites of abnormalities were in the following order: basal ganglia and thalami, 55.2%, frontal lobes, 23.8%, temporal lobes, 13%, parietal, 3.7%, insular and occipital lobes together, 4.6%.

Fluorine-18-fluorodeoxyglucose dual-head gamma camera coincidence imaging of recurrent colorectal carcinoma

We report our experience with coincidence detection imaging of 18F-fluorodeoxyglucose (FDG) using a dual-head gamma camera. Scanning of the pelvis and abdomen of a patient with recurrent colorectal carcinoma showed recurrent disease in the pelvic floor and the base of the urinary bladder and metastatic disease in the retroperitoneal space of the pelvis. Although the tumor involving the bladder and pelvic floor was detected by CT and magnetic resonance imaging (MRI), metastatic spread to the retroperitoneal nodes on the left side was detected only by 18F-FDG imaging. Based on the ultrasound, CT, MRI and cystoscopy, a local recurrence of cancer was presumed in our patient. An exploratory laparotomy was performed to resect the tumor in its entirety. At the time of surgery, the retroperitoneal metastasis in the pelvis was confirmed. Had the findings of the coincidence detection imaging study been considered, the patient would have been spared the surgical procedure.

Functional association between Arf and RalA in active phospholipase D complex

Activation of phospholipase D1 (PLD1) by Arf has been implicated in vesicle transport and membrane trafficking. PLD1 has also been shown to be associated with the small GTPase RalA, which functions downstream from Ras in a Ras-RalA GTPase cascade that facilitates intracellular signal transduction. Although PLD1 associates directly with RalA, RalA has no effect upon the activity of PLD1. However, PLD1 precipitated from cell lysates with immobilized glutathione S-transferase-RalA fusion protein is active. This suggests the presence of an additional activating factor in the active RalA-PLD1 complexes. Because Arf stimulates PLD1, we looked for the presence of Arf in the active RalA-PLD1 complexes isolated from v-Src- and v-Ras-transformed cell lysates. Low levels of Arf protein were detected in RalA-PLD1 complexes; however, if guanosine 5'-[gamma-thio]triphosphate was added to activate Arf and stimulate translocation to the membrane, high levels of Arf were precipitated by RalA from cell lysates. Interestingly, deletion of 11 amino-terminal amino acids unique to Ral GTPases, which abolished the ability of RalA to precipitate PLD activity, prevented the association between RalA and Arf. Brefeldin A, which inhibits Arf GDP-GTP exchange, inhibited PLD activity in v-Src- and v-Ras-transformed cells but not in the nontransformed cells, suggesting that the association of Arf with RalA is required for the increased PLD activity induced by v-Src and v-Ras. These data implicate Arf in the transduction of intracellular signals activated by v-Src and mediated by the Ras-RalA GTPase cascade. Because both Arf and PLD1 stimulate vesicle formation in the Golgi, these data raise the possibility that vesicle formation and trafficking may play a role in the transduction of intracellular signals.

RalA interacts directly with the Arf-responsive, PIP2-dependent phospholipase D1

RalA GTPase associates with a phospholipase D (PLD) that is activated in v-Src- and v-Ras-transformed cells. Two mammalian PLDs were recently cloned: PLD1, which is activated by Arf family GTPases and dependent upon phosphatidylinositol-4,5-bisphosphate (PIP2), and PLD2, which is also dependent upon PIP2, but not stimulated by Arf. Another PLD has been described that is stimulated by oleate. Evidence is provided that the RalA-assiciated PLD is PLD1. First, the PLD precipitated by RalA from murine fibroblasts was stimulated by Arf, dependent upon PIP2, and inhibited by oleate. Second, immobilized RalA precipitated PLD1 from sf9 insect cells overexpressing PLD1. Third, a series of RalA mutants precipitated PLD activity from both PLD1-expressing insect cells and murine fibroblasts with the same efficiency. And finally, immobilized RalA precipitated PLD1 from a purified PLD1 preparation. These data argue that RalA associates directly with the Arf-responsive, PIP2-dependent PLD1.

Effects of H/D substitution on thermal vibrations in piperazinium hexanoate-h11, d11

The crystal structures of piperazinium hexanoate-h11, 1/2C4H12N2(2+).C6H11O2-, and piperazinium hexanoate-d11, 1/2C4H12N2(2+).C6D11O2-, have been determined from neutron diffraction data collected at 15 K. Nuclear anisotropic displacement parameters have been analyzed to obtain the internal molecular displacements of the H and D nuclei, given by (u(obs)2)-(u(ext)2) where (u(ext)2) is the contribution assuming all H/D to be carried rigidly on the vibrating molecular framework consisting of the heavier nuclei. In both crystal structures the cation ring is well fitted by the rigid-body model and the anion chain by a model with two rigid segments. In the piperazinium cations the corresponding protons in the two structures have about the same internal vibrational directions and magnitudes except for the two N--H protons, perhaps owing to differences in N--H...O hydrogen bonding. The internal vibrations of corresponding H/D in the h11 and d11 anions have approximately the same vibrational directions. The internal mean-square displacements of the H nuclei are systematically greater than the values of the corresponding D nuclei by an average factor 1.7(3). For both anions, normal-mode analyses have been carried out using the force fields derived from ab initio quantum-mechanical calculations with HF/3-21G and HF/6-31G** basis sets. The values of the resultant H/D internal displacements for C--H(D) bond stretching and methylene out-of-plane vibrations are in good agreement with experiment. However, with either basis set, theory predicts methylene in-plane mean-square displacements significantly greater than the experimental values.

Involvement of Ral GTPase in v-Src-induced phospholipase D activation

An early response to the tyrosine kinase activity of v-Src is an increase in phospholipase D (PLD) activity, which leads to the generation of biologically active lipid second messengers, including phosphatidic acid, lysophosphatidic acid and diacylglycerol. We have recently demonstrated that v-Src-induced PLD activity is mediated by Ras, although Ras involvement was indirect, requiring a cytosolic factor for PLD activation. Ras interacts with and activates Ral-GDS, the exchange factor responsible for the activation of Ral GTPases. Here we report that this newly identified Ras/Ral signalling pathway mediates PLD activation by v-Src. PLD activity could be precipitated from v-Src-transformed cell lysates with immobilized RalA protein and with an anti-Ral antibody. A mutation to the region of RalA analogous to the 'effector domain' of Ras did not reduce the ability of RalA to complex with PLD, although deletion of a Ral-specific amino-terminal region did. Overexpression of RalA potentiated PLD activation by v-Src, and expression of dominant negative RalA mutants inhibited both v-Src- and v-Ras-induced PLD activity. Thus RalA is involved in the tyrosine kinase activation of PLD through its unique N terminus, and that PLD is a downstream target of a Ras/Ral GTPase cascade.

Ras mediates the activation of phospholipase D by v-Src

We demonstrated previously that v-Src activates a phospholipase D (PLD) activity (Song, J., Pfeffer, L.M., and Foster, D.A. (1991) Mol. Cell. Biol. 11, 4903-4908) and that this activation is dependent upon a G protein(s) (Jiang H., Alexandropoulos, K., Song, J., and Foster, D.A. (1994) Mol. Cell. Biol. 14, 3676-3682). An in vitro PLD assay was developed to study G protein involvement in v-Src-induced PLD activity. Maximal PLD activity in membranes isolated from v-Src-transformed cells was dependent upon both GTP and cytosol. In this report, we present three lines of evidence demonstrating that v-Src-induced PLD activity is mediated by Ras. First, a neutralizing Ras monoclonal antibody (Y13-259) inhibits PLD activity in membranes isolated from v-Src-transformed Balb/c 3T3 cells. Second, immobilized Ras protein depleted cytosol of the ability to stimulate PLD activity. This effect was dependent upon preloading immobilized Ras with GTP. Last, expression of a dominant negative Ras mutant in v-Src-transformed cells reduced PLD activity to the level observed in the nontransformed parental cells. These data establish a novel role for Ras in the regulation of PLD activity.

Crystal structure of piperazinium oleate at -150 degrees C

The crystal structure of piperazinium oleate ([C4H12N2]2+.2[C18H34O2]-) has been determined from X-ray diffraction data at -150 degrees C in order to study the oleate chain conformation and molecular packing. Differential scanning calorimetry shows three reversible crystalline state phase transitions (54.5, -34.8, and -54.8 degrees C) in the range from the melting point (84.8 degrees C) to -160 degrees C. The cell constants for a flash-frozen crystal at -150 degrees C are a = 5.630(2), b = 14.900(2), c = 24.825(4) A, alpha = 88.77(2), beta = 88.12(2), gamma = 80.38(2) degrees; Z = 2, space group P1; Dc = 1.05 g cm-3, m.p. = 84.8 degrees C. The cell constants are similar at room temperature except for a doubling of b at -150 degrees C. The crystal structure at -150 degrees C has been refined to R(F2) = 0.116 for 8410 independent reflections. There are two independent oleate anions (A and B), both having an overall extended conformation except for kinks that are different at the cis olefin group. The oleate A chain is ordered while the oleate B chain is disordered in two regions. Because of different torsion angles at bonds adjacent to the double bond, the B-chain olefin group adopts two configurations, one of which is predominant. From the olefin group to the terminal methyl group, the B-chain adopts one of two all-trans configurations with equal probability. It cannot be determined whether the two kinds of disorder are correlated. Taking into account the centrosymmetrically related oleate chains, the crystal structure contains at least six and possibly eight extended chain conformers with different kinks at the olefin group. Third and fourth order displacement parameters have been determined for the partially resolved atomic sites in the oleate B chain and these have been used to map probability density functions for the disordered atoms. The piperazinium cations are in a chair conformation. Each is hydrogen bonded to four oleate anions, forming an infinite ribbon parallel to (025). These ribbons are stacked upon each other to form a monolayer 24.8 A thick parallel to (001).

A Monte Carlo investigation of dual-energy-window scatter correction for volume-of-interest quantification in 99Tcm SPECT

Using Monte Carlo simulation of 99Tcm single-photon-emission computed tomography (SPECT), we investigate the effects of tissue-background activity, tumour location, patient size, uncertainty of energy windows, and definition of tumour region on the accuracy of quantification. The dual-energy-window method of correction for Compton scattering is employed and the multiplier which yields correct activity for the VI as a whole calculated. The model is usually a sphere containing radioactive water located within a cylinder filled with a more dilute solution of radioactivity. Two simulation codes are employed. Reconstruction is by ML-EM algorithm with attenuation compensation. The scatter multiplier depends only slightly on the sphere location or the cylinder diameter. It also depends little on whether correction is before or after reconstruction. At low background level, it changes with VOI size, but not at higher background. For a geometrical VOI, it is 1.25 at zero background, decreases sharply to 0.56 for equal concentrations, and is 0.44 when the background concentration is very large. Quantification is accurate (less than 9% error) if the test background is reasonably close to that used in setting the universal scatter-multiplier value, or if the test backgrounds are always large and so is the universal-value background, but not if the test backgrounds cover a large range of values including zero. Results largely agree with those from experiment after the experimental data with background is re-evaluated with prejudice.

CT-SPECT fusion plus conjugate views for determining dosimetry in iodine-131-monoclonal antibody therapy of lymphoma patients

A method for performing 131I quantitative SPECT imaging is described which uses the superimposition of markers placed on the skin to accomplish fusion of computed tomography (CT) and SPECT image sets.

METHODS

To calculate mean absorbed dose after administration of one of two 131I-labeled monoclonal antibodies (Mabs), the shape of the time-activity curve is measured by daily diagnostic conjugate views, the y-axis of that curve is normalized by a quantitative SPECT measurement (usually intra-therapy), and the tumor mass is deduced from a concurrent CT volume measurement. The method is applied to six B-cell non-Hodgkin's lymphoma patients.

RESULTS

For four tumors in three patients treated with the MB1 Mab, a correlation appears to be present between resulting mean absorbed dose and disease response. Including all dosimetric estimates for both antibodies, the range for the specific absorbed dose is within that found by others in treating B-cell lymphoma patients. Excluding a retreated anti-B1 patient, the tumor-specific absorbed dose during anti-B1 therapy is from 1.4 to 1.7 mGy/MBq. For the one anti-B1 patient, where quantitative SPECT and conjugate-view imaging was carried out back to back, the quantitative SPECT-measured activity was somewhat less for the spleen and much less for the tumor than that from conjugate views.

CONCLUSION

The quantitative SPECT plus conjugate views method may be of general utility for macro-dosimetry of 131I therapies.