Efficacy of laparoscopic surgery for loop colostomy: a propensity-score-matched analysis.

PURPOSE: Colostomy is a common procedure for fecal diversion, but the optimal colostomy approach is unclear in terms of surgical outcomes and stoma-related complications. The purpose of this study was to examine the efficacy and feasibility of laparoscopic loop colostomy. METHODS: This retrospective cohort study included patients who underwent loop colostomy at Shizuoka Cancer Center in Japan between April 2010 and March 2022. Patients were divided into two groups based on surgical approach: the laparoscopic (LAP) and open (OPEN) groups. Surgical outcomes and the incidences of stoma-related complications such as stomal prolapse (SP), parastomal hernia (PSH), and skin disorders (SD) were compared with and without propensity score matching. RESULTS: Of the 388 eligible patients, 180 (46%) were in the LAP group and 208 (54%) were in the OPEN group. The male-to-female ratio was 5.5:4.5 in the Lap group and was 5.3:4.7 in the OPEN group, respectively. The median age was 68 years (range, 31-88 years) in the LAP group and 65 years (range, 23-93 years) in the OPEN group, respectively. The LAP group, compared with the OPEN group, had a shorter operative time and lower incidences of surgical site infection (3.9% versus 16.3%, respectively; p < 0.01) and SD (11.7% versus 24.5%, respectively; p < 0.01). There was no significant difference between the LAP and OPEN groups in the incidence of SP (17.3% versus 17.3%, respectively) or PSH (8.9% versus 6.7%, respectively). After propensity score matching, the incidences of surgical site infection and SD were significantly lower in the LAP group than in the OPEN group, while there were no significant differences in the operative time or the incidences of SP and PSH. CONCLUSION: Our results suggest that laparoscopic surgery could be beneficial and feasible in loop colostomy.

Which is more important in the management of splenic flexure colon cancer: strict central lymph node dissection or adequate bowel resection margin?

BACKGROUND: What qualifies as optimal lymph node (LN) dissection in the surgical management of splenic flexure colon cancer (SFCC) still remains controversial because few studies have evaluated the distribution of LN metastasis of SFCC. The aim of this study was to clarify detailed distribution of LN metastasis and long-term outcomes of SFCC. METHODS: This retrospective study enrolled patients who had curative colectomy for primary transverse or descending colon cancer of pathological stage I, II, or III at a single high-volume cancer center between April 2002 and December 2018. The 538 eligible patients were divided into three groups: patients with SFCC (SFCC group, n = 168), patients with proximal transverse colon cancer (PTCC group, n = 290), and patients with distal descending colon cancer (DDCC group, n = 80). LNs were classified into horizontal (pericolic) and vertical (intermediate and main) nodes. Intermediate and main LN station numbers were defined according to the Japanese Society for Cancer of the Colon and Rectum classification. Distributions of LN metastasis and long-term outcomes were compared. RESULTS: In the SFCC group, the mean age was 67.3 ± 10.5 years and 110 patients (65.5%) were male. The proportion of patients with LN metastasis in the intermediate or main region was significantly lower in the SFCC group (8%) than in the PTCC (37%) (p < 0.01) or DDCC group (29%) (p < 0.01) in pathological stage III patients. In the SFCC group, the incidence of pericolic LN metastasis on the oral side of tumor (43%) was significantly higher than in the PTCC group (21%) (p < 0.01) and was similar to that in the DDCC group (42%) (p = 0.51), while in the SFCC group, the incidence of pericolic LN metastasis on the anal side of tumor (17%) was lower than in the PTCC group (31%) and was also similar to that in the DDCC group (21%). There were no significant differences in disease-specific survival rates among all groups. CONCLUSIONS: LN metastasis occurred mainly in the pericolic region, especially on the oral side of the tumor in SFCC. It may, therefore, be important to have an adequate bowel resection margin, especially on the oral side, for SFCC.

Robotic-assisted multivisceral resection for rectal cancer: short-term outcomes at a single center.

BACKGROUND: The safety and feasibility of robotic-assisted multivisceral resection for locally advanced rectal cancer remain unclear. The aim of this study was to assess the short-term outcomes of this procedure at our institution. METHODS: From December 2011 to December 2016, patients who underwent robotic-assisted multivisceral resection for rectal cancer were investigated. Patient demographics, treatment characteristics, perioperative outcomes, and pathological results were evaluated retrospectively. RESULTS: There were 31 patients; 17 men (54.8%) and 14 women (45.2%), with a median age of 65 years (range 40-82 years). Twenty-one patients (67.7%) had a cT4 tumor, 9 patients (29.0%) had a pT4b tumor, and all patients except one (96.8%) underwent complete resection of the primary tumor with negative resection margins. Eleven patients (35.5%) received neoadjuvant chemoradiation. The most commonly resected organ was the vaginal wall (n = 12, 38.7%), followed by the prostate (n = 10, 32.3%). Lateral lymph node dissection was performed in 20 patients (64.5%). The median operative time was 394 min (range 189-549 min), and the median blood loss was 41 mL (range 0-502 mL). None of the patients received intraoperative blood transfusions or required conversion to open. Overall, postoperative complications occurred in 11 patients (35.5%). The most frequent complication was urinary retention (n = 5, 16.1%), and none of the patients developed serious complications classified as Clavien-Dindo grades III-V. CONCLUSIONS: Robotic-assisted multivisceral resection for rectal cancer is safe and technically feasible.

Validation of a commercial serodiagnostic kit for diagnosing pulmonary Mycobacterium avium complex disease.

SETTING: A commercial serodiagnostic kit for diagnosing pulmonary disease due to Mycobacterium avium complex (MAC-PD) was developed and launched in Japan in 2011. OBJECTIVE: To evaluate the performance of this kit in routine clinical settings. METHODS: In this retrospective single-centre study, data on serum levels of anti-glycopeptidolipid (GPL) core IgA antibody (U/ml) measured using the kit were analysed in patients diagnosed with MAC-PD according to American Thoracic Society criteria, in those with pulmonary tuberculosis (PTB) or pulmonary M. kansasii disease and in healthy volunteers. RESULTS: The anti-GPL-core IgA antibody levels of serum were significantly higher (P < 0.0001) in patients with MAC-PD (n = 485) than in those with PTB (n = 133) or pulmonary M. kansasii disease (n = 23) or in healthy subjects (n = 265). When the cut-off level was set at 0.7 U/ml, the sensitivity and specificity were respectively 78.6% and 96.9%. Higher antibody levels were observed in patients with greater extent of disease on chest computed tomography (P < 0.0001). CONCLUSIONS: The serodiagnostic kit revealed good sensitivity and specificity. The antibody levels may reflect disease activity. Additional work is needed to determine whether the diagnostic assay could be used in conjunction with current diagnostic criteria to improve the diagnosis of MAC-PD.

Mechanism of oocyte maturation and ovulation and its application to seed production in the Japanese eel.

Reduction in eel resources and catches of glass eels as seedlings for aquaculture have been a serious concern in recent years in both Europe and East Asia. Thus, technical advancement to produce eel seeds for artificial cultivation is most desired. Fundamental information on oocyte maturation and ovulation and its application to artificial induction of sexual maturation are needed to produce good quality seeds of the Japanese eel. This review introduces hormonal mechanisms of cytoplasmic maturation (such as hydration, lipid coalescence, and clearing of the ooplasm) and the maturational competence (the ability to respond to maturation-inducing steroid) and nuclear maturation (germinal vesicle breakdown). In addition, previous and newly developed methods for induction of spawning have been described.

20ß-hydroxysteroid dehydrogenase gene promoter: potential role for cyclic AMP and xenobiotic responsive elements.

Teleostean 20ß-hydroxysteroid dehydrogenase (20ß-HSD) is involved in final oocyte maturation and steroid hormone metabolism. It has structural and functional similarities to mammalian carbonyl reductases that are involved in the metabolism of endogenous carbonyl and xenobiotic compounds. To understand the transcriptional regulation of 20ß-HSD, here we report the cloning of 20ß-HSD promoter from two fish species, rainbow trout and air-breathing catfish. Analysis of the promoter motifs, in silico identified the presence of several sites for transcription factor binding including cAMP, xenobiotic and steroid hormone responsive elements. Luciferase reporter assays with progressive deletion constructs demonstrated that 20ß-HSD type B of trout has no promoter activity while 20ß-HSD type A of trout and catfish 20ß-HSD promoters showed basal promoter activity. A TATA box flanked by a CAAT box is important for basal transcription. Deletion of cAMP responsive element in the promoter decreased basal promoter activity significantly. Reporter assays with forskolin and IBMX, drugs that increase intracellular cAMP induced the promoter activity over the basal level. Intriguingly, ß-nafthoflavone, an arylhydrocarbon receptor ligand, induced the 20ß-HSD promoter activity and is further evidenced by the induction of 20ß-HSD expression in the livers of catfish, in vivo. These results demonstrate for the first time that 20ß-HSD expression is not only modulated by cAMP but also by xenobiotics and further studies may provide significance to the ubiquitous distribution and broad substrate specificity of this enzyme.

Gender differences in tryptophan hydroxylase-2 mRNA, serotonin, and 5-hydroxytryptophan levels in the brain of catfish, Clarias gariepinus, during sex differentiation.

Tryptophan hydroxylase (tph) is the key regulator in serotonin (5-HT) biosynthesis that stimulates the release of GnRH and gonadotropins by acting at the level of hypothalamo-hypophyseal axis. In brain, 5-HT is expressed predominantly in preoptic area-hypothalamus (POA-HYP) region in teleosts. Therefore, in the present study we isolated tph2 from catfish brain to evaluate its expression pattern in male and female brains during early development. Tph2 cloned from catfish brain is 2.768 Kb in length which encodes predicted protein of 488 amino acid residues. The characterization of recombinant tph2 was done by transient transfection in CHO cells. Tissue distribution of tph2 revealed ubiquitous expression except ovary. Real time PCR analysis in discrete regions of adult male brain revealed that tph2 mRNA was abundant in the POA-HYP and optic tectum+cerebellum+thalamus (OCT) regions. Differential expression of tph2 was observed at mRNA and protein levels in the POA-HYP and OCT regions of male and female brains during development that further correlate with the 5-hydroxytryptophan (5-HTP) and 5-HT levels measured using HPLC method in these regions of male and female brains. Tph2 immunoreactive neurons were observed in different regions of brain at 50 days post hatch using catfish specific tph2 antibody. Changes in tph2 mRNA expression, 5-HTP, and 5-HT levels in the POA-HYP+OCT region of brains of methyltestosterone and para-chlorophenylalanine treated fishes during development further endorse our results. Based on our results, we propose that the serotonergic system is involved in brain sex differentiation in teleosts.

Force detecting gripper and flexible micro manipulator for neurosurgery.

In order to realize a less invasive robotic neurosurgery for the deeply seated tumor, a force detecting gripper with a flexible micro manipulator has been developed. Gripping force applied on the gripper is detected by strain gages fit on the gripper clip. Signal is conducted to the amplifier by the cables through the inner pipe of the manipulator. In order to approach to the deeply seated tumor through a narrow hole, a micro manipulator which can flex at the end part to face the gripper for the target and can rotate the closing direction of the gripper at the end of the manipulator has been developed. Some operation test showed that the developed manipulator can approach flexibly to the target, and the taking out force of a target on the soft material was detected clearly.

Cloning, expression and enzyme activity analysis of testicular 11beta-hydroxysteroid dehydrogenase during seasonal cycle and after hCG induction in air-breathing catfish Clarias gariepinus.

A full-length cDNA encoding 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) was cloned from testis of air-breathing catfish, Clarias gariepinus which showed high sequence homology to zebrafish and eel. The open reading frame of 11beta-HSD2 was then transfected to COS-7 cells, which converted 11beta-hydroxytestosterone (11-OHT) to 11-ketotestosterone (11-KT). Using NAD(+), 11beta-HSD2 from testicular microsomes oxidized 11-OHT with apparent K(m) 56+/-4nM and V(max) 55+/-6pmol/h/mgprotein values. Tissue distribution analysis revealed prominent expression in testis, anterior kidney, liver and gills. Expression of 11beta-HSD2 in testis and serum levels of 11-KT were high in the prespawning phase. Administration of human chorionic gonadotropin (hCG) during prespawning and resting phases revealed initial rise in 11beta-HSD2 transcript at 4h followed by gradual increase at 8h, 12h and peaking at 24h, only in testis of prespawning phase. Rate of conversion of 11-OHT to 11-KT by testicular microsomes during different testicular phases and after hCG administration corroborated well with the expression of 11beta-HSD2. Ontogeny study indicated that this enzyme is expressed during testicular development. Thus the spatio-temporal expression supported with putative dehydrogenase activity and circulating 11-KT levels clearly suggest a major role for 11beta-HSD2 during testicular differentiation and seasonal testicular cycle in catfish.

Dimorphic expression of tryptophan hydroxylase in the brain of XX and XY Nile tilapia during early development.

Serotonin (5-HT) is well known for modulating the release of GnRH and gonadotropin in teleosts. Reports on increased female:male ratio after the blockade of 5-HT biosynthesis proposed a role for 5-HT in brain sex differentiation. Two types of tryptophan hydroxylase (Tph), rate-limiting enzyme in the biosynthesis of 5-HT were cloned from vertebrates. In the present study, we cloned Tph from brain and evaluated its importance during early development of XX and XY Nile tilapia. Tph cloned from tilapia brain is 1888 bp in length and it encodes predicted protein of 462 amino acid residues. Tph activity of tilapia was confirmed by demonstrating the conversion of L-tryptophan to 5-hydroxy tryptophan by the recombinant protein after transient transfection of this cDNA clone in COS-7 cells. Northern blot identified single transcript around 2kb in male brain. Tissue distribution of Tph revealed high abundance in brain, kidney, liver and testis. Semi-quantitative RT-PCR revealed exclusive expression of Tph in the male brain from 5 to 20 days post hatch (dph) while in the female brain, it was from 25 dph. These results were authenticated by localization of Tph transcripts in olfactory bulb-telencephalon region of 11 dph male brain using in situ hybridization. Tph immunoreactivity (-ir) was also evident in the nucleus preopticus-periventricularis area of male brain as early as 12 dph. However, Tph-ir was observed in several regions of both male and female brain without any distinction from 30 dph. Dimorphic expression pattern of Tph during early brain development around the critical period (7-21 dph) of gonadal sex determination and differentiation may implicate a role for Tph in brain sex differentiation of tilapia.

Seabream GnRH immunoreactivity in brain and pituitary of XX and XY Nile tilapia, Oreochromis niloticus during early development.

Seabream gonadotropin-releasing hormone (sbGnRH)-the chief preoptic area-hypothalamus (POA-H) form of GnRH in tilapia is involved in sexual maturation. In this study, we investigated the qualitative changes in ontogeny of sbGnRH immunoreactivity (ir-), between sexes to understand its impending role during sex differentiation. For this, the differences in immunocytochemical localization of sbGnRH in genetically male (XY) and female (XX) fish were studied from 1 day after hatching (dah), through the critical period of sex differentiation (7-21 dah) to 40 dah and mature Nile tilapia. Specific antisera against sbGnRH were used for immunolocalization. SbGnRH ir- neurons were observed in POA-H as early as 5 and 15 dah in XY fish and XX fish, respectively. Higher ir- was detected in the POA-H of XY tilapia compared with XX population till 10 dah. There was a qualitative drop in sbGnRH ir- neurons/cell bodies in POA-H around 20 dah till 30 dah in XY population compared with other durations. SbGnRH ir- cells were detected in pituitary of XX fish by 15 dah and in XY fish around 10 dah but seemed to drop down by 20 dah in XY whereas it continued to remain steady in XX fish. The sbGnRH ir- in XY fish showed a rise from 35 dah and thence till 40 dah. This study revealed subtle differences in POA-H and pituitary sbGnRH ir- during early development between genetic male and female fish with possible implications in sex differentiation.

Description of International Caenorhabditis elegans Experiment first flight (ICE-FIRST).

Traveling, living and working in space is now a reality. The number of people and length of time in space is increasing. With new horizons for exploration it becomes more important to fully understand and provide countermeasures to the effects of the space environment on the human body. In addition, space provides a unique laboratory to study how life and physiologic functions adapt from the cellular level to that of the entire organism. Caenorhabditis elegans is a genetic model organism used to study physiology on Earth. Here we provide a description of the rationale, design, methods, and space culture validation of the ICE-FIRST payload, which engaged C. elegans researchers from four nations. Here we also show C. elegans growth and development proceeds essentially normally in a chemically defined liquid medium on board the International Space Station (10.9 day round trip). By setting flight constraints first and bringing together established C. elegans researchers second, we were able to use minimal stowage space to successfully return a total of 53 independent samples, each containing more than a hundred individual animals, to investigators within one year of experiment concept. We believe that in the future, bringing together individuals with knowledge of flight experiment operations, flight hardware, space biology, and genetic model organisms should yield similarly successful payloads.

Partial sequencing of sodA gene and its application to identification of Streptococcus dysgalactiae subsp. dysgalactiae isolated from farmed fish.

AIMS: To investigate the difference between Lancefield group C Streptococcus dysgalactiae (GCSD) strains isolated from diseased fish and animals by sequencing and phylogenetic analysis of the sodA gene. METHODS AND RESULTS: The sodA gene of Strep. dysgalactiae strains isolated from fish and animals were amplified and its nucleotide sequences were determined. Although 100% sequence identity was observed among fish GCSD strains, the determined sequences from animal isolates showed variations against fish isolate sequences. Thus, all fish GCSD strains were clearly separated from the GCSD strains of other origin by using phylogenetic tree analysis. In addition, the original primer set was designed based on the determined sequences for specifically amplify the sodA gene of fish GCSD strains. The primer set yield amplification products from only fish GCSD strains. CONCLUSIONS: By sequencing analysis of the sodA gene, the genetic divergence between Strep. dysgalactiae strains isolated from fish and mammals was demonstrated. Moreover, an original oligonucletide primer set, which could simply detect the genotype of fish GCSD strains was designed. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that Strep. dysgalactiae isolated from diseased fish could be distinguished from conventional GCSD strains by the difference in the sequence of the sodA gene.

Characterization of Lancefield group C Streptococcus dysgalactiae isolated from farmed fish.

A Lancefield group C streptococcal (GCS) infection caused by Streptococcus dysgalactiae that is characterized by severe necrotic lesions of the caudal peduncle has been an increasing cause of mortality in farmed fish such as amberjack, Seriola dumerili, and yellowtail, Seriola quinqueradiata, in the southern part of Kyushu, Japan. In this study, enzymatic profiles of GCS strains from fish and mammals were investigated using the API ZYM system, and genotypic characterization of GCS strains was performed using biased sinusoidal field gel electrophoresis (BSFGE). The partial sequence of the 16S-23S rDNA intergenic spacer region of the GCS strain isolates from fish and mammals was also compared. The API ZYM test indicated that it is difficult to differentiate isolates of S. dysgalactiae from fish and animals based on enzymological variations. In the BSFGE analysis, the macrorestriction profiles, which were obtained using SmaI or ApaI as a restriction enzyme, revealed variations between the fish and animal isolates. The partial sequence of the 16S-23S rDNA intergenic spacer region of all the tested fish isolates differed from all mammalian isolates in one or two nucleotides. The possibility of a clonal expansion of S. dysgalactiae strains in farmed fish was also suggested by the BSFGE profiles of fish isolates.

Postoperative host responses in elderly patients after gastrointestinal surgery.

BACKGROUND/AIMS: The age-associated dysregulation of hemodynamic, metabolic and immune responses contributes to the high incidence of complications after major abdominal surgery. METHODOLOGY: Ninety-five patients who underwent gastric resection (n=51) and colorectal resection (n=44) were divided according to age into Groups A (n=45, less than 70 years old), B (n=30, 70-79 years) and C (n=20, over 80 years). Flow cytometric analysis of CD4+ lymphocytes for interferon (IFN)-gamma and interleukin (IL)-4 production determined the Th1/2 balance. Energy expenditure was measured by indirect calorimetry, and hemodynamics were studied using pulse dye densitometry. RESULTS: Surgical procedures, operating time, blood loss and morbidity did not significantly differ among the three groups. The cardiac index (CI) in group A and B increased significantly over preoperative levels until POD 3, but there were no significant perioperative changes in the CI levels of group C. Resting energy expenditure levels changed similarly to those of CI. The postoperative Th1/2 ratio decreased from young to elderly to very elderly patients, although no differences were significant before surgery. The postoperative percentage of CD4+IFN-gamma +T cells (Th1) in group C decreased significantly despite of no significant changes in that of group A and B. In contrast, the ratio of CD4+IL-4+T cells (Th2) in the all groups significantly increased after surgery. CONCLUSIONS: Host responses in elderly patients after major abdominal surgery were more hyperdynamic and hypermetabolic than those of young patients. Postoperative dysregulation of the Th1/2 balance was also associated with aging. However, host responses appear to significantly differ between elderly and very elderly patients.

Thiourea-induced thyroid hormone depletion impairs testicular recrudescence in the air-breathing catfish, Clarias gariepinus.

We used thiourea-induced thyroid hormone depletion as a strategy to understand the influence of thyroid hormones on testicular recrudescence of the air-breathing catfish, Clarias gariepinus. Treatment with 0.03% thiourea via immersion for 21 days induced hypothyroidism (thyroid hormone depletion) as evidenced by significantly reduced serum T(3) levels. Thiourea-treated males had narrowed seminiferous lobules with fewer spermatozoa in testis, very little or no secretory fluid, reduced protein and sialic acid levels in seminal vesicles when compared to controls. The histological changes were accompanied by reduction in serum and tissue levels of testosterone (T) and 11-ketotestosterone (11-KT), a potent male specific androgen in fish. Qualitative changes in the localization of catfish gonadotropin-releasing hormone (cfGnRH) and luteinizing hormone (LH, heterologous system) revealed a reduction in the distribution of immunoreactive neuronal cells and fibers in thyroid depleted fish. Interestingly, thiourea-withdrawal group showed physiological and histological signs of recovery after 21 days such as reappearance of spermatozoa and partial restoration of 11-KT and T levels. These data demonstrate that thyroid hormones play a significant role in testicular function of catfish. The mechanism of action includes modulating sex steroids either directly or through the hypothalamo (GnRH)-hypophyseal (LH) axis.

Seabream GnRH: partial cDNA cloning, localization and stage-dependent expression in the ovary of snake head murrel, Channa striatus.

Vertebrate reproduction is under the neuroendocrine control of the hypothalamic decapeptide GnRH which synchronizes various reproductive events and influences other reproduction related aspects like spawning behavior and pheromonal action in fish. Multiple forms of GnRH peptides have been reported across diverse vertebrate and invertebrate classes. Here we report the partial seabream GnRH (sbGnRH) cDNA sequence cloned from the brain of Channa striatus (snake head murrel) a fresh water perciform with immense economic and medicinal value across Asiatic countries. sbGnRH mRNA was found in brain, gill and ovary of mature murrel with possible implications to the effect of GnRH on pheromonal phenomena and on reinitiation of oocyte meiosis. In keeping with the earlier reported role of GnRH in initiation of oocyte meiosis we here present evidence from RT-PCR, ICC demonstrating an increase in the level of sbGnRH mRNA in ovary from pre-vitellogenic to post-vitellogenic follicles.

Immunocytochemical localization of gonadotropins during the development of XX and XY Nile tilapia.

Gonadal development and steroidogenesis in teleosts is regulated by two gonadotropic hormones; luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Earlier studies in tilapia have shown that FSH-beta and LH-beta appear by 14 days after hatching (dah), results from the current study corroborate with these previous reports in tilapia. Here we demonstrate the appearance of LH in pituitary between 14 and 20 dah. In addition to this the present study primarily focuses on any possible differences in appearance of LH-beta and FSH-beta immunoreactivity between XX and XY population of Nile tilapia. LH immunoreactivity was found to be lower in pituitary of XX fish when compared to XY fish. The development of FSH-beta immunoreactivity in pituitary of the Nile tilapia is also presented. Overall, it remains to be established what significance these findings on the appearance of gonadotropins hold for sex differentiation in tilapia.

DNA modification in chick heart and cerebrum.

Heart muscle cells and cerebral neurons are known to lose the ability to proliferate and are called terminally differentiated cells. They are generated in appropriate numbers during embryogenesis and retained throughout adult life without turnover. We are interested in such a long-lived DNA. We isolated DNA from chick heart and cerebrum and compared it with DNA from other organs after incubation with DNase I. Single-strand breaks were assessed using a reaction system composed of DNA and Escherichia coli DNA polymerase. The DNA of both organs was relatively resistant to DNase I, and DNA modification occurred during embryogenesis. CIMS (chemical ionization mass spectrometry) indicated that the molecular mass of the deoxynucleoside of both DNAs was larger than that of the corresponding canonical deoxyribonucleoside by m/z 28 (or 30 for the protonated form). The difference between these deoxynucleosides is based on a difference in sugar constituents. Cerebral deoxynucleotides were analyzed by (13)C NMR. An extra signal near 173 ppm was observed, which was assigned to the amide carbonyl. We propose a model of the deoxynucleoside where a carbonyl residue exists between the base and the 2-deoxyribose moiety of the canonical deoxyribonucleoside.