Multidisciplinary handbook on pediatric nutritional support.
Explore the source record for details and available documents.
Child↗
Biomedical subjects
M Wong
Publications and source records attributed to M Wong.
Chondrocyte biosynthesis correlates with local tissue strain in statically compressed adult articular cartilage.
In this study, we investigated the depth-dependent metabolic and structural responses of adult articular cartilage to large-strain, static, unconfined compression. Changes in cell biosynthetic activity and several morphometry-based structural parameters (cell density, cell volume fraction, cell surface-area density, mean cell surface area, and mean cell volume) were measured at eight sites representing different depth-zones between the articular surface and the cartilage/bone border. In addition, local axial strain in the superficial, transitional, upper radial, and lower radial zones was estimated on the basis of the change in cell density values. Static compression of articular cartilage revealed a highly heterogeneous deformation profile through the depth of the sample as well as zone-specific changes in biosynthetic activity, as reflected by incorporation of [3H]proline. The axial strains in the top layers were greater than the applied surface-to-surface strain, whereas axial strains adjacent to the cartilage/bone border were significantly less than the applied strain. Zonal changes in cell density and axial strain that occurred during static compression correlated well with alterations in metabolic activity. These coordinated changes between cell biosynthesis and cartilage structure suggest that zone-specific variations in mechanical stimuli could be responsible for spatially varied patterns of cartilage metabolic activity under load.
Animals↗
The effect of chorion-uterine interaction upon free progesterone metabolism during advanced gestation in the guinea pig.
The in vitro fate of [3H]progesterone was studied after incubation with guinea pig tissues at 58/59 days (before pubic symphysis relaxation) and in the final week (post relaxation) of gestation. Buffered steroid was added to the fetal surface of chorion attached to the uterus or to the uterus alone. Neither the amount of recovered progesterone nor its metabolites (6.2% average conversion) differed between the two stages when only uterus was incubated. With chorion present, conversion averaged 28.3% at 58/59 days and 63.4% at the late stage. A 4.6-fold decrease in progesterone concentration, and 3.0-, 2.4- and 3.1-fold increases in the concentrations of 3alpha-hydroxy-5alpha-pregnan-20-one, 3beta-hydroxy-5alpha-pregnan-20-one and 5alpha-pregnane-3,20-dione, respectively, were found in the uterus in the late stage vs 58/59 days. Also, 2.8- and 6.4-fold decreases in progesterone concentration occurred in the myometrium and endometrium, respectively, from 58/59 days to the late stage. In endometrium, the concentrations of the 3alpha- and 3beta-isomers, and 5alpha-pregnane-3,20-dione, increased 2.6-, 2.6- and 5.0-fold, respectively. The above changes were all significant at P < 0.05 or better. Changes in the 3alpha-, 3beta- isomers and dione in the myometrium were not significant. The chorion-uterine interaction and gestation time thus affect the degree of progesterone conversion, and the amounts of metabolites reaching the uterus in the chorion-uterine in vitro system.
Animals↗
Screening for dementia: a preliminary study on the validity of the Chinese version of the Blessed-Roth Dementia Scale.
Blessed-Roth Dementia Scale has been one of the most widely used rating scales in dementia. Previous studies indicated that this behavioral assessment scale is a useful tool for differentiating elderly subjects with no or minimal intellectual decline from those with cognitive deterioration. In the present study, the authors examined the validity of the Chinese version of the Blessed-Roth Dementia Scale (CDS) in Hong Kong. A total of 106 Chinese subjects were recruited from a social center, an old-age home, and psychogeriatric outpatient clinics. At a cutoff score of 3 of 4, the CDS achieved a sensitivity of 90.5% and specificity of 98.1% in differentiating demented from healthy control subjects. In the Chinese population studied, the scale was readily acceptable and considered to be an useful adjunct in screening of dementia.
Aged↗
Dietary vitamin E supplementation inhibits thrombin-induced platelet aggregation, but not monocyte adhesiveness, in patients with hypercholesterolaemia.
Several recent studies have indicated the possible beneficial effects of antioxidants, specifically vitamin E, in primary and secondary coronary prevention. These studies suggest that a diet enriched in vitamin E is insufficient to have a significant protective effect, whereas supplements, in excess of 200 international units (IU) per day, are efficacious in preventing coronary disease in both men and women. The mechanisms by which vitamin E may exert its protection are uncertain, but, vitamin E is lipophilic and has been shown to inhibit the oxidative modification of low density lipoprotein (LDL), a process thought to be of crucial importance in atherogenesis. We have also previously shown that alpha-tocopherol (the biologically most potent isomer of vitamin E) has important direct effects on vascular endothelial and smooth muscle cells. In the present study we have investigated the effects of oral supplements of vitamin E (400 IU per day) on platelet and mononuclear cell function in patients with hypercholesterolaemia. We found that although vitamin E supplementation had no significant effect on mononuclear cell adhesion ex vivo, it had a significant effect on the thrombin-induced platelet aggregation (P < 0.01; ANOVA): 6 weeks after starting the vitamin E supplements, the mean EC50 for thrombin-induced aggregation increased 132% (P < 0.05; paired t-test) compared to treatment with placebo. The effects of vitamin E on platelet function may, in part, explain its anti-atherogenic properties.
Adult↗
Gradual phenotypic conversion associated with immortalization of cultured human mammary epithelial cells.
Examination of the process of immortal transformation in early passages of two human mammary epithelial cell (HMEC) lines suggests the involvement of an epigenetic step. These lines, 184A1 and 184B5, arose after in vitro exposure of finite lifespan 184 HMEC to a chemical carcinogen, and both are clonally derived. Although early-passage mass cultures of 184A1 and 184B5 maintained continuous slow growth, most individual cells lost proliferative ability. Uniform good growth did not occur until 20-30 passages after the lines first appeared. Early-passage cultures expressed little or no telomerase activity and telomeres continued to shorten with increasing passage. Telomerase activity was first detected when the telomeres became critically short, and activity levels gradually increased thereafter. Early-passage cultures had little or no ability to maintain growth in transforming growth factor-beta (TGFbeta); however, both mass cultures and clonal isolates showed a very gradual increase in the number of cells displaying progressively increased ability to maintain growth in TGFbeta. A strong correlation between capacity to maintain growth in the presence of TGFbeta and expression of telomerase activity was observed. We have used the term "conversion" to describe this process of gradual acquisition of increased growth capacity in the absence or presence of TGFbeta and reactivation of telomerase. We speculate that the development of extremely short telomeres may result in gradual, epigenetic-based changes in gene expression. Understanding the underlying mechanisms of HMEC conversion in vitro may provide new insight into the process of carcinogenic progression in vivo and offer novel modes for therapeutic intervention.
Adult↗
The modified Fuld Verbal Fluency Test: a validation study in Hong Kong.
Recent studies in the West have found that verbal fluency tests are useful in the detection of dementia. In this study, the Fuld Verbal Fluency Test (FVFT) was modified and tested for its usefulness as a screening instrument for differentiating demented from normal elderly Chinese in Hong Kong. Fifty-three normal and 56 demented subjects were administered the FVFT, the Cantonese version of the Mini-Mental State Examination (CMMSE), and the Chinese version of the Hamilton Depression Rating Scale. In addition to bearing significant correlation with the CMMSE, the verbal fluency scores for all semantic categories (animals, fruits, vegetables) were found to produce significant differentiation between the normal and demented groups. However, test-retest reliability for the individual verbal fluency scores was shown to be unsatisfactory, and a composite measure was recommended for use in future screening on the grounds of its enhanced reliability.
Aged↗
Epithelial cell growth and differentiation. III. Promoting diversity in the intestine: conversations between the microflora, epithelium, and diffuse GALT.
Homeostasis in the self-renewing mouse intestinal epithelium appears to be regulated in large part by cell nonautonomous mechanisms. The society of nonpathogenic bacteria that resides in the intestine is an important source of instructions that modify epithelial differentiation programs. The stability of this society is remarkable given its numerical, compositional, and spatial complexity, the openness of the ecosystem, and the fact that the epithelium is replaced so rapidly. The ability of components of this society to influence epithelial differentiation may represent a critical step in allowing specific groups of organisms to be assembled in specific regions of the gut. Simplified model systems have been created to define and dissect the conversations between microbe and host. These systems use inbred strains of mice that are raised under germ-free conditions and then monocontaminated with a single component of the microflora. The results suggest that a trialogue involving communications between the microflora, the epithelium, and the diffuse gut-associated lymphoid tissue (GALT) may play a key role in establishing and maintaining the spatial diversity of this remarkable ecosystem.
Animals↗
Repetitive and non-repetitive violent offending behaviour in male patients in a maximum security mental hospital--clinical and neuroimaging findings.
OBJECTIVE: To examine if different violent offending behaviours are associated with different clinical and neuroimaging profiles. METHOD: Thirty-nine schizophrenic and schizoaffective offenders from a maximum security mental hospital-20 repetitive violent offenders (RVOs) and 19 non-repetitive violent offenders (NRVOs)-were selected for clinical and neuroimaging assessments. RESULTS: Both groups had positive family history of mental illness and violence. Age, diagnosis, duration of illness, victim profiles and use of weapons at the time of the index offence were similar. RVOs had a higher prevalence of early parental separation, juvenile conduct problem, previous convictions of crimes not involving violence, impulsive suicide attempts, delusion of their lives being threatened at the time of the index offence and electroencephalographic (EEG) abnormalities localized to temporal lobes. NRVOs had a higher prevalence of sexual inexperience and command hallucinations to kill at the time of the index offence. Asymmetric gyral patterns at the temporo-parietal region were particularly common in RVOs and absent in NRVOs. Non-specific white matter changes in magnetic resonance imaging (MRI) and generalized cortical hypometabolism in positron emission tomography (PET) were present in both groups. CONCLUSIONS: Different structural and metabolic changes in the brain were associated with different violent offending behaviours. The complex interaction between violent behaviour, clinical features and neuroimaging findings in schizophrenia requires further studies.
Adult↗
Nutrition management in a pregnant comatose patient.
Major intracranial injury or disease during pregnancy resulting in a comatose state presents unique and complex management challenges. Our patient is a 34-year-old woman who suffered a closed-head injury associated with spousal abuse at 22 weeks' gestation. This injury resulted in a large right frontoparietal hematoma that was subsequently evacuated via a right frontotemporal craniotomy 5 days after the injury. She remained in a vegetative state postoperatively. Aggressive nutrition support was provided with enteral feedings through a nasoduodenal feeding tube. Mild oligohydramnios was detected at 30 weeks' gestation and was subsequently determined to be due to preterm premature rupture of membranes. She was managed until 33 weeks' gestation, when signs of chorioamnionitis were noted. She then underwent a primary cesarean delivery and was delivered of an appropriate-for-gestational-age 2150-g viable male infant. The patient had progressive improvement in her mental status with occupational and physical therapy and was discharged on the 29th postpartum day. This case presents the nutrition and medical challenges of maintaining adequate maternal and fetal health in a pregnant comatose patient.
Adult↗
Patterns of onset and cessation of drug use over the early part of the life course.
This study uses retrospective drug use histories to examine the timing of drug use behavior among young people participating in a large random probability survey of residents of the province of Ontario, Canada. Results reveal that the major risk period for initiation into alcohol, tobacco, and most illicit drugs begins around age 12 and is mostly over by age 22. For most drugs, peak periods of risk of initiation occur in the age range 15 to 19. For all categories of illicit drugs, results reveal high quit rates in the first few years of use followed by a sharp decline. Differences by gender reveal higher rates of onset for males for most drugs. Male drug users are significantly less likely than female users to quit using a drug. Results are discussed in terms of their implications for the development of primary prevention and early intervention programs for adolescents and young adults.
Adolescent↗
Acute effects of intravenous cocaine on pulmonary artery pressure and cardiac index in habitual crack smokers.
BACKGROUND: Some habitual crack cocaine smokers who deny IV drug abuse show decreased pulmonary transfer of carbon monoxide (DCO). We speculated that repeated elevations in pulmonary artery pressure (PAP) might cause pulmonary capillary damage and result in a lowered DCO, or that the reduction could be due to anoxic lung injury secondary to repeated episodes of cocaine-induced pulmonary vascular constriction. STUDY OBJECTIVE: Compare the acute effects of i.v. cocaine HCl and placebo on PAP, cardiac stroke volume, and cardiac output estimated indirectly by continuous Doppler echocardiography. DESIGN: A single-blind crossover study in which placebo always preceded the active drug. SUBJECTS: Ten current crack-smoking subjects, 32 to 47 years of age, with a history of limited previous i.v. cocaine use. METHODS: PAP, cardiac stroke volume, heart rate, and BP were measured continuously after injection of placebo followed by cocaine HCl (0.5 mg/kg). RESULTS: i.v. cocaine resulted in no significant change in PAP (-0.14 +/- 3.3[SD] mm Hg, 95% confidence interval [CI] for difference -2.48, +2.21). Stroke volume index showed no significant change after cocaine (-0.1 +/- 2.0 mL; 95% CI, -1.5, +1.3). Heart rate showed a significant increase (10.0 +/- 7.2 min-1; p = 0.0017, 95% CI, +4.9, +15.1). Cardiac index showed a significant increase (0.48 +/- 0.32 L/min; p = 0.0012, 95% CI, +0.25, +0.71). Pulmonary vascular resistance showed no significant change (-44 +/- 101 dyne.s.cm-5/m2, 95% CI, -116, +29). CONCLUSIONS: i.v. cocaine HCl does not cause short-term increases in PAP or stroke volume index, but causes an increase in cardiac index due to its chronotropic effect.
Adult↗
An action research study into the development of nurses as reflective practitioners.
This study adopted an action research approach in addressing the question: How could nurses be prepared to be reflective practitioners? The study took place among a group of registered nurses who enrolled in the first year of their degree studies at the Hong Kong Polytechnic University. The methods of data collection included observation, interview, students' written material, and teacher reflection. The experience of this study suggested that teachers and students should be partners in the promotion of reflective learning among students. As teachers reflected on their teaching arrangement and the progress of student learning, students could accordingly be offered appropriate guidance. Throughout the span of their studies, students learned to gradually develop different perspectives in viewing professional nursing practice. The reconceptualization of nursing practice helped students challenge taken-for-granted views and eventually reconstruct their conception of nursing.
Curriculum↗
Evidence for RANTES, monocyte chemotactic protein-1, and macrophage inflammatory protein-1 beta expression in Kawasaki disease.
OBJECTIVE: Patients with Kawasaki disease mount an immune response directed to their abnormally stimulated vascular endothelium, that is associated with vascular inflammation and injury and a predisposition to arterial aneurysm formation. This suggests that specific pro-inflammatory cytokines may mediate these hyperreactive responses. The selective chemoattractant and activation effects of chemokines on lymphocytes identifies them as potential candidates in mediating selective inflammatory processes in Kawasaki disease. We examined peripheral blood from patients with Kawasaki disease for chemokine gene expression. METHODS: Consecutive samples from 14 patients during the acute, subacute, and convalescent phases of their illness were collected and elaborated for RANTES, macrophage inflammatory protein-1 beta (MIP-1 beta) and monocyte chemotactic protein-1 (MCP-1) expression. RESULTS: RANTES and MCP-1 gene expression levels were significantly elevated in 12 of the 14 patients, and MIP-1 beta gene expression was elevated in 13 of the 14 patients. There was no obvious correlation between clinical phase of the disease and chemokine expression level, yet elevated expression levels were detected in all phases, including the convalescent phase, when laboratory evidence of lymphocyte activation has been shown to return to normal. Serial samples showed persistence or increased expression of chemokine genes into the convalescent phase in patients with coronary artery lesions. CONCLUSION: Chemokine mediated inflammatory events may persist in the convalescent phase of Kawasaki disease and may contribute to further risk of vascular endothelial cell injury, specifically coronary aneurysm formation.
Chemokine CCL2↗
Estrogen: nontranscriptional signaling pathway.
The long-term, genomic actions of estrogen and other steroid hormones are now relatively well understood. In this process, steroids bind to a cytoplasmic/nuclear receptor and the hormone receptor complex that, in turn, binds to DNA and triggers RNA-dependent protein synthesis. This process produces a response over time periods of several minutes to hours to days. Estrogen also exerts a variety of short-term effects (observed in milliseconds to minutes) on target organs that are not compatible with the classical genomic mechanism. These short-term, nontranscriptional actions are thought to be neuromodulatory in nature and critical for cell-cell communication. This chapter discusses current evidence for nontranscriptional effects of estrogen, with major emphasis on electrophysiological results demonstrating rapid, estrogen-induced changes in neuronal excitability. The mechanisms for nontranscriptional estrogen effects are also considered. These mechanisms include nonspecific influences on the lipid bilayer, specific binding to novel membrane receptors, direct modulation of neurotransmitter-ion channel complexes, and direct activation of second messenger systems. Particular attention will be focused on studies from our laboratory investigating mechanisms of estrogenic potentiation of kainate-induced currents in hippocampal neurons. Finally, the physiological relevance of short-term estrogenic actions will be addressed.
Animals↗
Steroidogenic factor 1 plays multiple roles in endocrine development and function.
The nuclear hormone receptor family comprises a group of structurally related transcriptional regulators that mediate the actions of diverse ligands, including steroid hormones, thyroid hormone, vitamin D, and retinoids. The nuclear receptor family also contains members for which activating ligands have not been identified-the orphan nuclear receptors. One of these orphan nuclear receptors, steroidogenic factor 1 (SF-1), has emerged as an essential regulator of steroidogenic cell function within the adrenal cortex and gonads; SF-1 also plays important roles in reproduction at all three levels of the hypothalamic-pituitary-gonadal axis. First identified as a tissue-specific regulator of the transcription of the cytochrome P450 steroid hydroxylases, considerably broader roles for SF-1 were revealed by genetic studies in mice lacking SF-1 due to targeted gene disruption. These SF-1-knockout mice had agenesis of their adrenal glands and gonads, male-to-female sex reversal of their internal and external genitalia, impaired gonadotrope function, and agenesis of the ventromedial hypothalamic nucleus. These studies delineated essential roles of SF-1 in regulating endocrine differentiation and function at multiple levels. Despite these insights into roles of SF-1, the precise mechanisms by which SF-1 exerts its multiple effects remain to be determined. This review highlights experiments that have established SF-1 as a pivotal determinant of endocrine differentiation and function and identifies areas in which additional studies are needed to expand our understanding of SF-1 action.
Animals↗
Protein purification in preparative scale of mammalian cell culture-derived products. Strategies for extra high purity.
Explore the source record for details and available documents.
Animals↗
Bacterial mutagens in the urine of patients under tinidazole treatment.
Tinidazole is an antiparasitic drug belonging to the 5-nitroimidazole family. It is prescribed against protozoal infestations and is widely used in Mexico as well as other underdeveloped countries where infectious diseases are the first cause of children mortality. The drug is a direct mutagen in Salmonella typhimurium TA100 strain and the presence of S9 mixture did not modify its mutagenic effect. At low doses no mutagenicity was detected with strains TA100NR, TA98 or UTH8414 (Uvr+ derivative of TA100). Urine from four patients under tinidazole treatment exhibited a mutagenic activity on strain TA100, greater than the expected from the tinidazole concentrations determined by high-performance liquid chromatography (HPLC). Components from the urine samples were separated on thin-layer chromatography (TLC) plates, and their mutagenic effects tested by direct application of the Salmonella assay onto sections of the developed chromatoplate. The Rf of one component (0.62) corresponded to the one obtained for a tinidazole standard and showed the expected mutagenicity, while a second component with an Rf=0.39, exhibited a mutagenic potency slightly greater than the observed for tinidazole; however, as in the case of the drug itself, reduction of the nitro group was necessary for a mutagenic activity.
Adult↗