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Biomedical subjects

J C Walton

Publications and source records attributed to J C Walton.

At least 19 recordsLinked to original sources
PubMed2006

Sex-specific influences of vasopressin on human social communication.

Arginine vasopressin (AVP) and related peptides affect social behaviors in numerous species, but AVP influences on human social functions have not yet been established. Here, we describe how intranasal AVP administration differentially affects social communication in men and women, and we propose a mechanism through which it may exert those influences. In men, AVP stimulates agonistic facial motor patterns in response to the faces of unfamiliar men and decreases perceptions of the friendliness of those faces. In contrast, in women, AVP stimulates affiliative facial motor patterns in response to the faces of unfamiliar women and increases perceptions of the friendliness of those faces. AVP also affected autonomic responsiveness to threatening faces and increased anxiety, which may underlie both communication patterns by promoting different social strategies in stressful contexts in men and women.

Administration, Intranasal↗
PubMed2004

Visual sex discrimination in goldfish: seasonal, sexual, and androgenic influences.

The olfactory signals used by goldfish for sexual and aggressive communication have been studied extensively, but little work has addressed the role of other sensory modalities in social communication in this species. We therefore investigated the role that visual stimuli play in sex discrimination and the ability of androgens, which masculinize courtship behavior, to affect behavioral responses toward female visual stimuli. We found that males selectively orient toward female visual stimuli during the breeding season but not outside it, whereas prostaglandin F2-alpha (PGF2alpha)-injected females do not differentially approach male and female visual stimuli, even during the breeding season. Implanting adult females with testosterone (T) and 11-ketotestosterone (KT), however, induced orientation responses toward female visual stimuli similar to those observed in males. These results indicate that visual sexual stimuli are likely important for reproductive signaling in goldfish, potentially helping males identify ovulating females from a distance in a shoal of fish, and that androgens can influence mechanisms associated with orientation responses toward such stimuli.

Androgens↗
PubMed2000

Plastic bread-bag clips in the gastrointestinal tract: report of 5 cases and review of the literature.

Plastic bread-bag clips have been identified as a cause of local perforation or obstruction at many sites in the gastrointestinal tract. This study is the largest case series yet reported, consisting of 3 cases presenting as small-bowel perforation, 1 case in which the clip was found incidentally in the small bowel at laparotomy during vascular surgery and 1 case in which the clip was found incidentally in the small bowel at autopsy. In all cases there was no radiographic evidence to suggest a foreign body in the gastrointestinal tract. People older than 60 years of age who have either partial or full dentures seem to be particularly at risk for the accidental ingestion of these devices. If accidentally ingested, plastic bread-bag clips represent a significant health hazard. As the population ages, small-bowel perforation secondary to ingestion of such clips may occur with increasing frequency. The authors recommend elimination or redesign of the clips, to prevent their being swallowed and becoming impacted in the small bowel or to allow them to be identified in the gastrointestinal tract by conventional radiography.

Age Factors↗
PubMed2000

Inhibition of human platelet aggregation by a novel S-nitrosothiol is abolished by haemoglobin and red blood cells in vitro: implications for anti-thrombotic therapy.

1. S-Nitrosothiols are nitric oxide (NO) donor drugs that have been shown to inhibit platelet aggregation in platelet rich plasma (PRP) in vitro and to inhibit platelet activation in vivo. The aim of this study was to compare the platelet effects of a novel S-nitrosated glyco-amino acid, RIG200, with an established S-nitrosothiol, S-nitrosoglutathione (GSNO) in PRP, and to investigate the effects of cell-free haemoglobin and red blood cells on S-nitrosothiol-mediated inhibition of platelet aggregation. 2. The effects of GSNO and RIG200 in collagen (2.5 microg ml(-1))-induced platelet aggregation in PRP and whole blood were investigated in vitro. Both compounds were found to be powerful inhibitors of aggregation in PRP, and RIG200 was significantly more potent (IC(50)=2.0 microM for GSNO and 0.8 microM for RIG200; P=0.04). 3. Neither compound inhibited aggregation in whole blood, even at concentrations of 100 microM. Red blood cell concentrations as low as 1% of the haematocrit, and cell-free haemoglobin (> or = 2.5 microM), significantly reduced their inhibitory effects on platelets. 4. Experiments involving measurement of cyclic GMP levels, electrochemical detection of NO and electron paramagnetic resonance of haemoglobin in red blood cells, indicated that scavenging of NO generated from S-nitrosothiols by haemoglobin was responsible for the lack of effect of S-nitrosothiols on platelets in whole blood. 5. These studies suggest that scavenging of NO by haemoglobin in blood might limit the therapeutic application of S-nitrosothiols as anti-platelet agents.

Adult↗
PubMed1998

Recognizing and managing Clostridium difficile-associated diarrhea.

Clostridium difficile-associated diarrhea poses a significant physical risk and cost to the recovery of hospitalized older adults. C. difficile is responsible for 75% or more of the diarrhea-associated enteric infections acquired during a hospital stay (Gerding, Johnson, Peterson, Mulligan, & Silva, 1995). C. difficile is easily spread by direct or indirect contact, therefore placing other patients at great risk for contamination by this organism. Nursing plays a significant role in early identification, management, and control of the spread of this potentially lethal infection.

Adult↗
PubMed1998

Evaluating physical and behavioral changes in older adults.

In older adults, subtle and sometime not so subtle physical or behavior changes can act as early warning signs of changing status. Nonspecific signs and symptoms occurring in older adults such as decline in previous functional capacity, urinary incontinence, anorexia, confusion, or unexplained falls may be signs of infection, medication interaction, dehydration, constipation, or sleep deprivation. Nurses, by critically assessing the situation early, may identify a developing problem. Prompt and early diagnosis of the underlying problem may save costly extended hospitalization or even prevent life-threatening complications.

Aged↗
PubMed1997

Managing unlicensed assistive personnel: tips for improving quality outcomes.

Today, nursing care delivery requires effective management of unlicensed assistive personnel (UAP). With capitation, each member of the care delivery team is critical to assuring quality patient outcomes. Yet, staff nurses may not fully understand how to maximize the performance of these workers. To be effective managers, nurses must understand how learning styles, cultural diversity, and multicultural team building improve the performance of UAP and the entire care delivery team. These variables are critical elements in effective communication, delegation, supervision, behavior modification, and team building with UAP.

Communication↗
PubMed1996

Cutaneous ganglioneuromas: a case report and review of the literature.

The occurrence of ganglioneuromas outside the sympathetic chains of the mediastinum and abdomen in the nonpediatric age group is rare. We report the case of a solitary cutaneous ganglioneuroma on the abdomen of a 52-year-old woman. The lesion, which had been present for 20 years, measured 1.2 cm in greatest dimension. Unmyelinated axons, Schwann cells, and scattered mature ganglion cells were identified by histochemistry, immunohistochemistry, and electron microscopy. Only three similar cases have been reported in the literature to date. Ganglioneuromas have also been reported as mature components of metastatic neuroblastomas and in association with plexiform neurofibromas, neither of which was present in this case. The pathogenesis of this lesion is unclear, however, aberrant migration of neural crest elements is the most likely explanation. The possible trophic role of sex steroids is also discussed. Although no follow-up series exist, local excision should he curative considering the small size and histologically benign appearance of the lesion.

Female↗
PubMed1996

Hospital nurses' views about physical restraint use with older patients.

1. A survey of knowledge, practice and attitudes about physical restraints was completed by nursing staff (RN, LPN, CNA) from four hospitals. 2. Nurses from both geriatric and geropsychiatric units reported significantly more educational activities about restraint use than did nurses on medical units. 3. RNs had the highest knowledge scores (56%), but lacked specific information about the dangers associated with restraint use. 4. While education about restraints is important, staff need role models who can help them problem solve and examine alternatives to restraints.

Aged↗
PubMed1994

Immunohistochemical localization, messenger ribonucleic acid abundance, and activity of 15-hydroxyprostaglandin dehydrogenase in placenta and fetal membranes during term and preterm labor.

Type 1 15-hydroxyprostaglandin dehydrogenase (PGDH) is the main enzyme responsible for the metabolism of prostaglandin E2 (PGE2) and PGF2 alpha. To examine the possibility that a deficiency of PGDH might contribute to preterm labor, we measured localization of immunoreactive (IR-) PGDH, PGDH mRNA, and PGDH enzyme activity in chorio-decidua, placenta, and amnion in patients after term elective cesarean section (n = 9), after spontaneous vaginal term delivery (n = 10), and at idiopathic preterm labor (PTL) in the absence of infection (< 36 weeks gestation; n = 11). Localization of IR-PGDH was determined in additional specimens of membranes after PTL with infection (n = 13) and without (n = 37). IR-PGDH was localized in syncytiotrophoblast and intermediate trophoblasts in placenta and in the trophoblast layer of extraplacental chorion, but was absent from amnion in all patient groups. In chorion, the number of IR-positive trophoblasts was significantly reduced in the idiopathic PTL group compared to those in the other groups. The relative abundance of PGDH mRNA in the chorio-decidua, but not the placenta, from spontaneous labor and PTL was significantly less than that after cesarean section. PGDH mRNA in chorio-decidua from preterm patients correlated with PGDH enzyme activity. Undetectable or low IR-PGDH in chorionic trophoblasts was also associated with low enzyme activity. These results suggest that there exists a subset of patients that present in PTL because of reduced PGDH expression in chorionic trophoblasts. We suggest that this relative deficiency would allow PGs synthesized in the amnion or chorion to escape metabolism in the chorion and thereby contribute to the stimulus to idiopathic PTL.

Amnion↗
PubMed1993

Transitional cell carcinoma of the renal pelvis with choriocarcinomatous differentiation. Immunohistochemical and immunoelectron microscopic assessment of human chorionic gonadotropin production by transitional cell carcinoma of the urinary bladder.

BACKGROUND: There have been 12 documented cases of choriocarcinoma arising in the urinary bladder, either alone or in combination with other epithelial tumors. It has been shown that some high-grade transitional cell carcinomas (TCC), without obvious syncytiotrophoblastic elements, can produce human chorionic gonadotrophins (HCG). METHODS: A case of choriocarcinoma, in association with high-grade TCC of the renal pelvis, was encountered in an 80-year-old man. For additional evaluation of HCG production by TCC, 25 consecutive cases of invasive high-grade TCC of the bladder were stained with an anti-HCG antibody. Immunogold staining also was performed in two of the cases studied. RESULTS: Immunoperoxidase staining of the renal pelvis tumor showed focal positivity for HCG within the TCC and a more intense reaction as the tumor cells differentiated into choriocarcinoma elements. Seven of the 25 cases (28%) displayed varying degrees of reactivity within individual cells or groups of cells. In an additional case, typical syncytiotrophoblastic giant cells without cytotrophoblasts were seen in a high-grade TCC. Immunogold studies demonstrated positive labeling in the cytoplasm of carcinoma cells in a case of TCC without syncytiotrophoblasts and in the syncytiotrophoblastic giant cells in the one case in which these were present. CONCLUSIONS: The findings support a metaplastic origin of cases of choriocarcinoma arising primarily in the urothelial tract.

Aged↗
PubMed1992

Localization of 15-hydroxy prostaglandin dehydrogenase in human fetal membranes, decidua, and placenta during pregnancy.

Localization of NAD(+)-dependent 15-hydroxy prostaglandin dehydrogenase (type I-PGDH) may influence local concentrations of bioactive eicosanoids within intrauterine tissues. In early pregnancy (6-9 weeks), IR-PGDH was localized by immunohistochemistry to syncytiotrophoblast, cytotrophoblast, and intermediate trophoblast of placenta. At 23-30 weeks of gestation and at term IR-PGDH was present in syncytiotrophoblast and intermediate trophoblast, but not in cytotrophoblast in placenta. It was absent from amnion, and distributed within the trophoblast cell layer of extraplacental chorion variably at 23-30 weeks, but consistently at term. We speculate that PGDH is ideally localized to metabolize and to maintain low concentrations of primary prostaglandins in the fetal membranes for much of gestation.

Decidua↗
PubMed1992

Immunohistochemical localization of 3 beta-hydroxy-5-ene-steroid dehydrogenase/delta 5----delta 4 isomerase in human placenta and fetal membranes throughout gestation.

The regulation of steroid production by the placenta and fetal membranes is important for both the maintenance of pregnancy and the timing of parturition. 3 beta-Hydroxy-5-ene-steroid dehydrogenase/delta 5----delta 4-isomerase (3 beta HSD) catalyzes an obligatory step in the biosynthesis of steroid hormones. We have determined the localization of 3 beta HSD in the human placenta, fetal membranes, and umbilical cord throughout gestation by immunohistochemical analysis, using a polyclonal antibody raised in rabbits against a purified preparation of human placental 3 beta HSD. In placenta, immunoreactive (IR-) 3 beta HSD was localized in the syncytiotrophoblast and intermediate trophoblast cells at both villous and extravillous sites, but not in cytotrophoblast cells from 6 weeks gestation to term. At 6-7 weeks gestation, IR-3 beta HSD was distributed in the cytoplasm of syncytiotrophoblast in about half of placental villi. By 12-14 weeks, the syncytiotrophoblast of all placental villi stained positively for 3 beta HSD. In the fetal membranes, strong IR-3 beta HSD staining was found in the trophoblast and reticular layers of chorion and in invasive trophoblast cells in decidua, and weakly in decidual stromal cells and amniotic epithelium. No IR-3 beta HSD was found in amnion on the placental plate, but in the umbilical cord, IR-3 beta HSD was present in the amniotic epithelium and also in fibroblast cells in Warton's jelly. These observations demonstrate that the localization of 3 beta HSD immunoreactivity and, therefore, the presumed sites of delta 5- to delta 4-steroid interconversion throughout gestation are principally the syncytiotrophoblast and intermediate trophoblast cells in placenta and the trophoblast cells in chorion and decidua in fetal membranes.

Extraembryonic Membranes↗
PubMed1991

The localization and distribution of corticotropin-releasing hormone in the human placenta and fetal membranes throughout gestation.

Using immunohistochemical techniques, we have determined the localization and distribution of CRH immunoreactivity (CRH-IR) in the human placenta, fetal membranes, decidua, and umbilical cord. Tissues were obtained at 6-8 weeks of pregnancy, at term, in association with premature birth, and from patients with pregnancy-induced hypertension or diabetes mellitus. A polyclonal antibody to the epithelial cell marker cytokeratin was used to identify trophoblast cells. CRH-IR was not detected in placenta or decidua at 6-8 weeks gestation. In tissues obtained after idiopathic premature delivery after 21 weeks gestation, positive CRH staining was found in placenta in syncytiotrophoblast and intermediate trophoblast, but not cytotrophoblast. CRH-IR was present in intermediate trophoblast cells that had invaded maternal blood vessels in decidua basalis. In the fetal membranes, CRH-IR was localized in the epithelium and subepithelial cells of amnion, in the trophoblast layer, in some cells of the reticular and cellular layers of chorion, and in some stromal cells and invasive trophoblast cells of decidua. CRH-IR was found in the amniotic epithelium of the umbilical cord and in the musculature of the umbilical vessels. This pattern of distribution of CRH-IR was found in tissues from 21 weeks gestation to term and postterm, and was similar in tissues examined from patients with pregnancy-induced hypertension and diabetes mellitus. These results show clearly that in placenta and membranes, CRH is localized primarily to syncytiotrophoblast and intermediate trophoblast, but not to cytotrophoblast cells. We suggest that the localization of CRH-IR is consistent with CRH affecting paracrine/autocrine interactions within the placenta, fetal membranes, and decidua that may be involved in the maturation of the fetal hypothalamic-pituitary-adrenal axis and in the stimulus and maintainance of labor.

Amnion↗
PubMed1991

Anterior segment mesenchymal dysgenesis associated with partial duplication of the short arm of chromosome 2.

We present a case of partial duplication of the short arm of chromosome 2 (karyotype 46,XX, dup [2p21-2p25]) in a newborn girl. The infant was born at 41 weeks of gestation and died approximately 3 hours after birth. At autopsy the characteristic dysmorphic features (hypertelorism, high, prominent forehead, micrognathia and low-set, malformed ears) and numerous other congenital malformations were observed. Bilateral microcornea with opacities was noted. Histopathological examination of the eyes showed dysgenesis of Bowman's membrane, with glycosaminoglycan deposition and a series of structural anomalies that form part of the anterior segment mesenchymal dysgenesis (ASMD) complex. To our knowledge this is the first case of partial duplication of the short arm of chromosome 2 in which the ocular histopathological features have been studied. Our case provides a further example of the association of ASMD with a chromosomal abnormality.

Abnormalities, Multiple↗
PubMed1990

Immunocytochemical distribution and localization of 15-hydroxyprostaglandin dehydrogenase in human fetal membranes, decidua, and placenta.

Biochemical studies have shown the presence of type I oxidized nicotinamide-adenine dinucleotide-dependent 15-hydroxyprostaglandin dehydrogenase in human fetal membranes, decidua, and placenta. However, the localization of prostaglandin dehydrogenase within these tissues is not known. Because the distribution of prostaglandin dehydrogenase may affect the concentration of prostaglandins that reach the myometrium, we used immunocytochemistry to localize immunoreactive prostaglandin dehydrogenase in fetal membranes and placenta. We also examined whether this distribution changed with labor. Tissues were collected at term elective cesarean section or after term spontaneous labor and delivery, were fixed, embeded, and sectioned at 5 microns. Immunoreactive prostaglandin dehydrogenase was determined with a polyclonal primary antibody to human placental prostaglandin dehydrogenase and visualized with the avidin-biotin procedure. Epithelial and epithelium-derived cells were identified by positive staining with a polyclonal antikeratin primary antibody. Cytokeratin staining was observed in amniotic epithelium, trophoblast layer of chorion, invading trophoblast in decidua, and all subsets of trophoblast in the placenta. Immunoreactive prostaglandin dehydrogenase was localized to the trophoblast layer of chorion, invading trophoblast in decidua, and in syncytiotrophoblast and intermediate trophoblast but not cytotrophoblast in the placenta. In chorion, approximately 50% to 60% of the nonvacuolated trophoblast cells stained positively for prostaglandin dehydrogenase. There was no change in the localization of immunoreactive prostaglandin dehydrogenase in any tissue in association with labor.

Amnion↗
PubMed1990

Electron spin resonance study of free radicals generated from retinyl- and ionyl-derivatives.

Free radicals generated from alpha- and beta-ionyl bromides gave well resolved ESR spectra, but retinyl bromide and chloride gave only broad signals. Delocalised radicals were also spectroscopically observed on hydrogen abstraction from alpha-ionane, alpha-ionyltrimethylsilylether and buten-3-ynyl-2,6,6-trimethyl-2-cyclohexene. Retinyl and beta-ionyl radicals, derived from the corresponding xanthates, were successfully spin trapped with nitrosodurene. The results suggested that the secondary sites C(7) and C(9) were the most reactive in the beta-ionyl radical and that the secondary sites C(7) and C(11) and probably the primary site C(15) were the most reactive in the retinyl radical.

Butylated Hydroxytoluene↗