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Biomedical subjects

J Jones

Publications and source records attributed to J Jones.

At least 325 records · Page 18Linked to original sources
PubMed1997

A candidate model for Angelman syndrome in the mouse.

Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are well-recognized examples of imprinting in humans. They occur most commonly with paternal and maternal 15q11-13 deletions, but also with maternal and paternal disomy. Both syndromes have also occurred more rarely in association with smaller deletions seemingly causing abnormal imprinting. A putative mouse model of PWS, occurring with maternal duplication (partial maternal disomy) for the homologous region, has been described in a previous paper but, although a second imprinting effect that could have provided a mouse model of AS was found, it appeared to be associated with a slightly different region of the chromosome. Here, we provide evidence that the same region is in fact involved and further demonstrate that animals with paternal duplication for the region exhibit characteristics of AS patients. A mouse model of AS is, therefore, strongly indicated.

Aneuploidy↗
PubMed1997

Cytochrome oxidase in Alzheimer's disease: biochemical, histochemical, and immunohistochemical analyses of the visual and other systems.

Defects in oxidative metabolism have been implicated in Alzheimer's disease (AD). The present study evaluated the level of cytochrome oxidase (C.O.), an indicator of neuronal oxidative capacity, in various brain regions of post-mortem AD and control patients. We found a statistically significant reduction in C.O. levels in all cortical areas examined, including the primary and secondary visual cortices. In addition, all layers of the dorsal lateral geniculate nucleus and sublaminae of the primary visual cortex in AD cases examined suffered a reduction in their relative C.O. activity and protein amount. Our results suggest a generalized suppression of oxidative metabolism throughout the cortex, as well as in a major subcortical visual center in AD. Such hypometabolism may form the basis for not only deficits in higher cortical functions, but also a variety of visual dysfunctions known to occur in AD.

Alzheimer Disease↗
PubMed1997

Cardiology.

Emergency cardiac problems are a frequent and significant occurrence in the daily life of the emergency physician. The first part of this article discusses some of the pearls and pitfalls of caring for the cardiac patient ranging from treating wide-complex tachycardia and troubleshooting pacemaker malfunction to diagnosing acute myocardial infarction in the setting of bundle branch blocks. The second part of this article updates the reader on several of the newer technologies and treatments, such as transesophageal echocardiography and intravenous amiodarone, now in use in the emergency department setting.

Amiodarone↗
PubMed1997

Integrins and oral cancer.

Integrins are a family of heterodimeric, cation-dependent cell membrane adhesion molecules which mediate cell-cell and cell-matrix interactions. They play a fundamental role in the maintenance of tissue integrity and in the regulation of cell proliferation, growth, differentiation and migration. It is not surprising, therefore, that integrins have been implicated in neoplasia and tumour progression and metastasis. Integrin expression and function are altered in malignant cells, although no specific integrin has been implicated in transformation to the malignant phenotype and changes in integrin expression vary both between and within different tumour types. In oral squamous cell carcinomas there is variable loss or reduced expression of beta 1 integrins and of alpha 6 beta 4, which correlates to loss of basement membrane proteins and is most extensive in poorly differentiated lesions. There are also changes in the repertoire of alpha v integrin expression with de novo expression of alpha v beta 6 which may be important in tumour cell migration. Conversely there is reduced expression of alpha v beta 5. In vitro studies suggest that this integrin may be important in oral neoplasia since alpha v-negative cell lines show a malignant phenotype which can be reversed by transfection of the missing integrin. Because alterations in integrin expression in oral cancers are so variable, it seems unlikely that they will be useful as prognostic markers. However, studies of integrin expression and function are increasing our understanding of cell interactions in oral cancer and may pave the way for novel therapeutic interventions to arrest the progression of individual tumours.

Carcinoma, Squamous Cell↗
PubMed1997

Factor structure, reliability, and validity of the Pain Catastrophizing Scale.

The Pain Catastrophizing Scale (PCS; Sullivan et al., Psychol. Assess. 7, 524-532, 1995) has recently been developed to assess three components of catastrophizing: rumination, magnification, and helplessness. We conducted three studies to evaluate the factor structure, reliability, and validity of the PCS. In Study I, we conducted principal-components analysis with oblique rotation to replicate the three factors of the PCS. Gender differences on the original PCS subscales were also analyzed. In Study II, we conducted confirmatory factor analyses to evaluate the adequacy of fit of four alternative models. We also evaluated evidence for concurrent and discriminant validity. In Study III, we evaluated the ability of the PCS and subscales to differentiate between the responses of clinic (students seeking treatment) and nonclinic undergraduate samples. Also, in the clinic sample, we evaluated evidence of concurrent and predictive validity for the PCS. The internal consistency reliability indices for the total PCS and subscales were examined in all three studies. Limitations and future directions are discussed.

Adult↗
PubMed1997

Acheson revisited: public health medicine ten years after the Acheson Report.

The issue of communicable disease control and the role of public health medicine is once more of considerable concern, particularly in the light of recent outbreaks and NHS reorganisations. Ten years ago, following similar concerns, the Acheson Report highlighted several issues with striking parallels to the present day. These included uncertainty over the future and role of public health medicine following repeated Health Service reorganisations. The Report recommended the expansion of the specialty in both communicable disease control and public health medicine in general, and a more clearly defined role for public health medicine. Successive health authority mergers and the specialty's inclusion as part of management costs have meant that the Report's findings have yet to be fully implemented. In fact, the establishment of public health medicine consultants (CsPHM) has fallen by a quarter since 1992. A further review of the public health function is required if the specialty is not to fragment, and if able doctors are not to be deterred from entering the specialty. Such a review should include the removal of the specialty from management costs, and the clarification & standardisation of the roles of the Director of Public Health (DPH), CPHM and other members of the multi-disciplinary public health team, as well as identifying possible organisational locations for the public health function.

Communicable Disease Control↗
PubMed1997

A prospective randomized study of glutamine-enriched parenteral compared with enteral feeding in postoperative patients.

Plasma amino acids were measured in 17 postoperative subjects randomly assigned to receive for > or = 5 d tube feeding or total parenteral nutrition (TPN) that had identical energy, nitrogen, and glutamine contents. Subjects required gastric or pancreatic surgery for malignancy and were well-matched for age and body mass index. Tube feeding or TPN began on postoperative day 1 and advanced in daily 25% increments to meet goals of 105 kJ . kg body wt-1 . d-1, 1.5 g protein . kg body wt-1 . d-1, and 0.3 g glutamine . kg body wt-1 . d-1. Delivered energy, nitrogen, and glutamine were closely matched on day 4. Nitrogen balance and plasma proteins did not differ significantly between feeding groups. Total indispensable amino acids, branched-chain amino acids, and glutamine declined 25% on postoperative day 1 compared with preoperative day 0. Indispensable and branched-chain amino acid concentrations were restored with 5 d of either tube feeding or TPN. Glutamine concentrations did not differ significantly by feeding group, though a trend suggested that glutamine recovered more slowly in the tube-fed than in the TPN-fed subjects. Plasma amino acids otherwise reflected formula composition with ratios of valine to leucine of 1.24 and 3.69 mumol/L in subjects receiving 5 d of tube feeding or TPN, respectively. These findings suggest that glutamine-enriched tube feeding and TPN can result in similar profiles for most plasma amino acids at carefully matched doses.

Adolescent↗
PubMed1997

Microtubule organization and chromatin configurations in hamster oocytes during fertilization and parthenogenetic activation, and after insemination with human sperm.

The cytoskeletal components of hamster oocytes, zygotes, and spontaneously activated parthogenotes were examined after immunocytochemical labeling. Microtubules were found only in the anastral, tangentially arranged second meiotic spindle of unfertilized oocytes. Taxol treatment of unfertilized oocytes greatly augmented astral microtubules in both the metaphase II spindle and the cortex. Disruption of the meiotic spindle microtubules with nocodazole resulted in cortical chromosomal scattering. During hamster sperm incorporation and pronuclear formation, no sperm aster was detected in association with the male DNA. Instead, a large overlapping array of microtubules assembled in the cortex. By mitosis, this interphase array disassembled and an anastral metaphase spindle formed. Microtubule and chromatin configurations were also imaged in hamster oocytes injected with human sperm. Astral microtubules were absent from the sperm centrosome. The implications of these results are discussed in relation to the hamster oocyte penetration assay, a test commonly used by in vitro fertilization clinics to demonstrate the fertilizing ability of human sperm. We conclude that since hamsters and humans follow different methods of centrosome inheritance, maternal and paternal, respectively, the hamster may be an inappropriate model for exploring microtubule and centrosomal defects in humans or for assaying postinsemination forms of human male fertility defects.

Animals↗
PubMed1997

ADHD is associated with early initiation of cigarette smoking in children and adolescents.

OBJECTIVE: The association between attention-deficit hyperactivity disorder (ADHD) and cigarette smoking in children and adolescents was evaluated. METHOD: Subjects were 6- to 17-year-old boys with DSM-III-R ADHD (n = 128) and non-ADHD comparison boys (n = 109) followed prospectively for 4 years into mid-adolescence. Information on cigarette smoking was obtained in a standardized manner blind to the proband's clinical status. Cox proportional hazard models were used to predict cigarette smoking at follow-up using baseline characteristics as predictors. RESULTS: ADHD was a significant predictor of cigarette smoking at follow-up into mid-adolescence. Our findings also revealed that ADHD was associated with an early initiation of cigarette smoking. This was the case even after controlling for socioeconomic status, IQ, and psychiatric comorbidity. In addition, among children with ADHD, there was a significant positive association between cigarette smoking and conduct, major depressive, and anxiety disorders. CONCLUSIONS: ADHD, particularly the comorbid subtype, is a significant risk factor for early initiation of cigarette smoking in children and adolescents. Considering the prevalence and early childhood onset of ADHD, these findings highlight the importance of smoking prevention and cessation programs for children and adolescents with ADHD.

Adolescent↗
PubMed1997

A pilot study of neuropsychological function in girls with ADHD.

OBJECTIVE: Attention-deficit hyperactivity disorder (ADHD) is known to have neuropsychological consequences that are evident from psychological tests and from measures of school failure. However, most available data are based on studies of boys. Our goal was to assess, in this pilot study, whether ADHD in girls expressed neuropsychological features similar to those found in boys. METHOD: Subjects were 43 girls, aged 6 to 17 years, with DSM-III-R ADHD and 36 comparison girls without ADHD. Information on neuropsychological performance was obtained in a standardized manner blind to clinical status. RESULTS: Girls with ADHD were significantly more impaired on estimated IQ than comparison girls despite being matched on other demographic variables. Relative to comparison girls, the girls with ADHD were also significantly more impaired on the Freedom From Distractibility subtests of the WISC-R and on arithmetic and reading achievement scores. Although their mean performance on executive function tests was generally poorer than that of control girls, there were no statistically significant differences on these measures. CONCLUSIONS: Girls with ADHD have impairments in some tests of attention and achievement. However, neuropsychological performance on tests of executive function was less impaired than that previously documented in boys with ADHD. If confirmed in a larger sample, these findings suggest that girls with ADHD may be less vulnerable to executive function deficits than boys.

Adolescent↗
PubMed1997

Effect of shock timing on defibrillation success.

The goal of this study was to determine whether delivering transvenous defibrillation shocks, coordinated with the up/down-slope VF waveform patterns in the shocking lead, would improve the probability of successful defibrillation. Anesthetized swine (32-38 kg, n = 8) were implanted with an RV-->SVC + SQArray transvenous system to measure VF waveform patterns and to deliver shocks. The shocks were generated by a Cardiac Pacemakers Inc. biphasic waveform generator. Energy required for 50% success probability (E50) was determined using the multishock up-down protocol. VF was repeatedly induced and defibrillation shocks at E50 were given after 10 seconds. The defibrillation outcome, delivered energy (Ed), peak voltage (V), peak current (I), system impedance (Z) and VF waveform pattern at the time of shock were recorded and measured. Out of a total of 685 shocks, 324 (47%) succeeded and 361 (53%) failed. The Ed, V, I, and Z were similar for the two defibrillation outcome groups (success or failure). VF patterns were classified as high or low amplitude at the time of the shock based on the peak-to-peak amplitude of signals recorded between the shocking electrodes. Shocks that coincided with high amplitude VF patterns were further divided into shocks that occurred on the up-slope or on the down-slope. The probability of success when the E50 shocks were coincident with high or low amplitude fibrillation did not differ significantly (Student's t-test: 46% vs 48%. P = NS). However, during high amplitude fibrillation, shocks delivered on the up-slope were significantly more successful than those delivered on the down-slope (Chi-square: 67% vs 39%; P < 0.001). These results suggest that delivering defibrillation shocks during the up-slope of the high amplitude signal in the shocking lead may improve the probability of successful defibrillation of ICDs.

Animals↗
PubMed1997

Changes in the expression of alpha v integrins in oral squamous cell carcinomas.

Integrins are cell surface adhesion molecules that regulate normal cellular interactions; aberrant integrin expression is believed to play a role in tumour invasion and metastasis. The alpha v subunit is capable of forming heterodimers with several beta subunits but not all the heterodimers expressed in oral epithelium have been investigated. We have examined the distribution of alpha v integrins in normal buccal mucosa and seventeen oral squamous cell carcinomas. Antibodies to the alpha v subunit and alpha v beta 5 heterodimer stained normal epithelium, with strong expression in the basal layers and weaker staining in the more superficial layers. The beta 3 and beta 6 subunits were not expressed in normal epithelium. Anti-alpha v and anti-alpha v beta 5 antibodies stained all the squamous cell carcinomas, but the pattern of expression was variable both within and between tumours. Poorly differentiated tumours showed the weakest staining and often had areas showing loss of expression. beta 6 was expressed in all of the carcinomas, indicating new expression of the alpha v beta 6 integrin in malignant oral epithelium. These results suggest that alterations in alpha v integrins may contribute to the behaviour of malignant epithelium and that alpha v beta 6 expression may play a role in tumour progression.

Antigens, Neoplasm↗
PubMed1997

Eccentric contractions decrease glucose transporter transcription rate, mRNA, and protein in skeletal muscle.

We have recently shown that eccentric contractions (ECs; forced lengthening of active muscle) elicit a delayed decrease in glucose transporter (GLUT-4) protein content in rat skeletal muscle and a decrease in subsequent contraction-stimulated glucose transport. Here, we investigate whether this decrease in total GLUT-4 protein after prior ECs is due to changes in GLUT-4 gene transcription rate and GLUT-4 mRNA level. Furthermore, the effect of prior ECs on sarcolemmal GLUT-4 protein content in plasma membrane (PM) vesicles isolated from contraction-stimulated muscle was determined. Rat gastrocnemius muscle was electrically stimulated for ECs, and the contralateral muscle served, as unstimulated control (UC). Two days later, the total GLUT-4 protein content was decreased by 50% (P < 0.05) and 32% (P < 0.05) in the white and red gastrocnemius muscle, respectively. Furthermore, the GLUT-4 mRNA concentration was decreased by 41% (P < 0.05) in both the white and red gastrocnemius muscle. Moreover, the GLUT-4 transcription rate, determined by nuclear run-on analysis, was decreased by 75% (P < 0.05) in mixed EC gastrocnemius muscle compared with UC muscle. PM vesicles were isolated from EC and UC muscle after 15 min of isometric contractions. The PM GLUT-4 protein content was reduced by 51% (P < 0.05) in EC muscle compared with UC muscle. In conclusion, 2 days after ECs, the GLUT-4 transcription rate, GLUT-4 mRNA, and GLUT-4 protein content were decreased in rat skeletal muscle. Moreover, the PM GLUT-4 protein content in contraction-stimulated muscle was decreased. We suggest that eccentric muscle contractions decrease muscle GLUT-4 transcription rate, resulting in a lower GLUT-4 protein content, which in turn decreases the number of GLUT-4 transporters translocated to the sarcolemma, ultimately leading to decreased contraction-induced muscle glucose transport.

Animals↗
PubMed1997

The Intensity of Home Care Acuity Scale. Part one.

Competition and consumer demand for lower-cost health services are affecting how patients receive home care. To help support field staff, one agency created an quantitative tool--Intensity of Home Care Acuity Scale.

California↗
PubMed1997

Further evidence of an association between attention-deficit/hyperactivity disorder and cigarette smoking. Findings from a high-risk sample of siblings.

The authors investigated the relationship between attention-deficit/hyperactivity disorder (ADHD) and cigarette smoking in siblings of ADHD and non-ADHD probands. They conducted a 4-year follow-up of siblings from ADHD and control-group families. In the siblings of ADHD probands, ADHD was associated with higher rates and earlier onset of cigarette smoking. There was also a significant positive association between cigarette smoking and conduct disorder, major depression, and drug abuse in the siblings, even after adjusting for confounding variables. Moreover, smoking was found to be familial among ADHD families but not control-group families. Our findings indicate that ADHD is a risk factor for early initiation of cigarette smoking in the high-risk siblings of ADHD probands.

Adolescent↗
PubMed1997

Studies on the time-course of ethanol's acute effects on skeletal muscle protein synthesis: comparison with acute changes in proteolytic activity.

A study of the effects of ethanol on skeletal muscle protein synthesis and protease activities was carried out in young male Wistar rats (150 g) for up to 24 hr after a single intraperitoneal dose of 75 mmol of ethanol/kg of body weight. At 20 min, the mean blood ethanol levels were 448 mg/dl. This level dropped steadily to zero through the following 24 hr. Compared with pair-fed controls, significant reductions in total protein, RNA, and DNA contents were seen only after 24 hr in all skeletal muscles studied: changes were more marked in the muscles containing large proportions of type II fibers. In plantaris muscle, the fractional rate of protein synthesis (ks, %/day) did not fall 20 min after dosage but was reduced after 1 hr by 23% (p < 0.001), and by 63% after 24 hr, compared with control saline-injected rats (p < 0.001). This effect was independent of dietary intake because, compared with the pair-fed group, the 24-hr ethanol-treated rats still showed a 52% decrease in fractional rates of protein synthesis (p < 0.001). Smaller reductions in ks were seen in soleus muscles in response to ethanol at 24 hr (-39%, p < 0.001). The activities of a variety of lysosomal and nonlysosomal proteases in plantaris muscle of 24-hr treated rats were not significantly affected by ethanol. Only alanyl- and tripeptidyl-aminopeptidase activities were reduced significantly (26%, p < 0.05 and 39%, p < 0.01, respectively). These results suggest that the muscle compositional changes seen over acute periods of ethanol toxicity are predominantly associated with impaired synthesis of protein and that the contribution of cellular proteolytic systems may be minimal. The effects of ethanol on skeletal muscle protein metabolism are greater in muscles containing a predominance of type II fibers than in those containing mainly type I fibers. Ethanol's effects on muscle may be influenced by hormonal changes after 24 hr, because protein synthesis is still compromised and free plasma T3 and corticosterone are altered at this time-point.

Alcoholism↗