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Biomedical subjects

R Rao

Publications and source records attributed to R Rao.

At least 109 records · Page 6Linked to original sources
PubMed1997

Attitudes toward death: a community study of octoagenarians and nonagenarians.

Attitudes to death were explored in 125 community residents aged 81 and older. Those people who thought about dying had less frequent contact with their interview informant; those who thought about death more frequently showed less severe cognitive impairment, a greater severity of depressive symptoms, and were more likely to be unmarried and were more commonly reported to be depressed by their interview informant. Worries about dying showed no association with sociodemographic or clinical variables. The commonest category of response from spontaneous comments was concerning the circumstances of dying. The results are discussed in light of other research findings, and emphasize the influence of low mood and social factors on death attitudes. This may have implications for closer examination of such attitudes in the assessment of depression and suicidal risk as well as in the care of the dying.

Aged↗
PubMed1997

Systemic lupus erythematosus, thrombocytopenia, microangiopathic haemolytic anaemia and anti-CD36 antibodies.

Thrombocytopenia in patients with acute systemic lupus erythematosus (SLE) frequently presents the clinician with considerable diagnostic and therapeutic difficulties. In this Grand Round, we present a 48-yr-old woman with a 7 yr history of lupus, who presented with acute proliferative glomerulonephritis and nephrotic syndrome, pneumonia, profound hypocomplementaemia and a severe microangiopathic haemolytic anaemia with associated thrombocytopenia. Her thrombocytopenia proved initially refractory to conventional immunosuppressive therapy, and corticosteroids, and resolved only with plasma exchange and repeated fresh frozen plasma infusions. Serological testing revealed high-titre antinuclear antibodies (ANA) and markedly raised antibodies to double-stranded (ds) DNA, but no significant elevation in anticardiolipin antibodies. Platelet-associated IgG and IgM and antibodies to the CD36 glycoprotein antigen, expressed on platelets and endothelium, were detected in the serum. We address some of the difficult diagnostic and management issues raised by this complex patient and the possible immunopathological links between antibodies to CD36, immune-mediated red cell destruction, thrombocytopenia and thrombotic microangiopathic haemolytic anaemia.

Anemia, Hemolytic, Autoimmune↗
PubMed1997

An international study of the exposure of children to traffic.

OBJECTIVES: To examine the extent of international differences in children's exposure to traffic as pedestrians or bicyclists. DESIGN: Children's travel patterns were surveyed using a parent-child administered questionnaire. Children were sampled via primary schools, using a probability cluster sampling design. SETTING: Six cities in five countries: Melbourne and Perth (Australia), Montreal (Canada), Auckland (New Zealand), Umeå (Sweden), and Baltimore (USA). SUBJECTS: Children aged 6 and 9 years. MAIN OUTCOME MEASURES: Modes of travel on the school-home journey, total daily time spent walking, and the average daily number of roads crossed. MAIN FINDINGS: Responses were obtained from the parents of 13423 children. There are distinct patterns of children's travel in the six cities studied. Children's travel in the three Australasian cities, Melbourne, Perth and Auckland, is characterised by high car use, low levels of bicycling, and a steep decline in walking with increasing car ownership. In these cities, over a third of the children sampled spent less than five minutes walking per day. In Montreal, walking and public transport were the most common modes of travel. In Umeå, walking and bicycling predominated, with very low use of motorised transport. In comparison with children in the Australasian and North American cities, children in Umeå spend more time walking, with 87% of children walking for more than five minutes per day. CONCLUSIONS: There are large international differences in the extent to which children walk and cycle. These findings would suggest that differences in 'exposure to risk' may be an important contributor to international differences in pedestrian injury rates. There are also substantial differences in pedestrian exposure to risk by levels of car ownership-differences that may explain socioeconomic differentials in pedestrian injury rates.

Australia↗
PubMed1997

Antagonist-stimulated internalization of the G protein-coupled cholecystokinin receptor.

Receptor-mediated endocytosis has been observed after agonist occupation of several G protein-coupled receptors, which contributes to the desensitization response to agonist stimulation; however, the cellular signals required to initiate this process are unclear. In this study, we developed and characterized a new antagonist analogue of cholecystokinin (D-Tyr-Gly-[(Nle28,31,D-Trp30)cholecystokinin-26-32]-phen eth yl ester) that can be tagged with a fluorescent rhodamine and radioiodinated. This has permitted us to demonstrate that antagonist occupation of the cholecystokinin receptor also results in receptor internalization, which dissociates this response from second messenger signaling activities and receptor phosphorylation. Immunolocalization of this receptor after occupation with an established nonpeptidyl antagonist confirmed this phenomenon. Antagonist-induced receptor internalization probably results from stabilization of the receptor in a conformation that exposes a domain critical to directing it into the clathrin-dependent endocytic pathway. This work provides evidence for a new and independent mechanism for receptor internalization, provides a mechanism for the rarely observed phenomenon of antagonist-induced desensitization, and raises important issues regarding the approach to establish optimal treatment regimens for antagonist drugs.

Binding, Competitive↗
PubMed1997

Suicidal thinking in community residents over eighty.

OBJECTIVE MAIN OBJECTIVE: to study the relationship between suicidal thinking and both cognitive impairment and depression. DESIGN: Random sample selected for interview, all of whom were a cohort in a pre-existing epidemiological study of dementia. SETTING: Community residents. PATIENTS AND OTHER PARTICIPANTS: Participants aged over 81. Study excluded the following: moved out of area/died/ too frail/severe communication difficulties/refused interview, refusal by GP/family/carers, 300 names selected at random from database. 170 eligible participants approached: 31 refused, 125 interviewed, 125 informants approached for interview; 118 interviewed. MAIN OUTCOME MEASURES: CAMDEX, 15-item Geriatric Depression Scale (GDS), and Scale for Suicidal Ideation (SSI) (including informant versions of latter 2 scales). RESULTS: 9 people showed suicidal thinking, all women: 6 had clinical evidence of cardiovascular/cerebrovascular disease. Those with suicidal thinking showed higher CAMDEX depression scores, weaker strength of the wish to go on living, higher rates of expressing wish to die and higher rates of depressive illness and mixed DAT/multi-infarct dementia as primary psychiatric diagnoses. No significant associations between suicidal thinking and GDS scores, Alzheimer-type dementia alone, awareness of memory difficulties or severity of dementia. CONCLUSIONS: Results show association between suicidal thinking and both depression and mixed DAT/multi-infarct dementia, but do not support an association between suicidal thinking and awareness of memory problems/severity of dementia. Given the methodological limitations, the significance of the results should be viewed with caution. Further exploration of the role of cerebrovascular disease in depressive disorder is suggested.

Activities of Daily Living↗
PubMed1997

Children's exposure to traffic and risk of pedestrian injury in an urban setting.

Pedestrian injuries to children represent a major urban health problem in the United States. Thousands of children each year are struck by moving motor vehicles; such collisions result in numerous hospitalizations and deaths. At particular risk are young school-age children between the ages of 5 and 9 years. Using a survey methodology, we collected data regarding the method by which children in an urban setting travel to and from school, in addition to the number of streets they cross in a typical school day. This information was compared with data from police records on street intersection locations of pedestrian collisions. There is a wide variation in the number of streets children cross in 1 day, calculated as the number of streets crossed in the entire day, not only those crossed to and from school. Children whose parents own a car and home cross an average of 3.7 streets per day, whereas children whose parents do not own both a car and home cross an average of 5.4 streets per day; this difference is highly significant (P < 0.0001). The largest differences in traffic exposure are between families reporting car- and-home ownership (x = 3.70 streets) versus those who do not own both a car and home (x = 5.39 streets) (Mann-Whitney = -5.5, P < 0.0001). There is a significant correlation between the proportion of children driven home from school and the rate of pedestrian injury in different regions of Baltimore. In areas where children are driven home, rates of pedestrian injury are significantly lower, whereas in areas where children walk home, rates of pedestrian injury are high (r = -0.79, P < 0.01). This study underscores the importance of adapting the child's environment to prevent injury. Interventions that alter the nature of the hazard are indicated. Changing the environment may ultimately prove more useful than attempting to change children's behavior.

Accidents, Traffic↗
PubMed1997

Annular pancreas.

Explore the source record for details and available documents.

Anastomosis, Surgical↗
PubMed1996

Synthesis and expression of genes encoding putative insect neuropeptide precursors in tobacco.

Neuropeptides are the key molecules in a multiplicity of physiological processes and their use in pest control has recently been suggested. Most neuropeptides are produced in the form of a precursor that is cleaved by proteolysis to yield various biologically active peptides. To mimic this structure, a method has been developed for synthesizing genes that code for putative polyneuropeptide precursors. As a model neuropeptide, the 5-amino-acid proctolin, one of the best studied invertebrate neuropeptides, functioning both as a visceral and a skeletal neuromuscular transmitter, was chosen. The synthetic gene was introduced into bacteria and tobacco plants, where it was efficiently transcribed. We present our results as a possible approach for the expression, in a variety of organisms, of synthetic genes coding for a wide repertoire of insect neuropeptides.

Amino Acid Sequence↗
PubMed1996

The relationship between longitudinal clinical course and sleep and cortisol changes in adolescent depression.

This study examined the relationship between longitudinal clinical course and sleep and cortisol findings in adolescent unipolar major depressive disorder (MDD). Subjects were 28 adolescents (15.4 +/- 1.3 years) systematically diagnosed with unipolar MDD and 35 group-matched normal controls who participated in EEG sleep and neuroendocrine studies. Follow-up clinical assessments were conducted 7.0 +/- 0.5 years later in 94% of the original cohort. Although initial group comparisons failed to show significant differences in biologic measures, analyses incorporating clinical follow-up reveal that changes in sleep and cortisol measures are associated with differential longitudinal course. Normal controls who would develop depression after the biologic studies had shown significantly higher density of rapid eye movements (REM) and a trend for reduced REM latency compared to controls with no psychiatric disorder at follow-up. Depressed subjects with a recurrent unipolar course showed a trend towards elevated plasma cortisol near sleep onset compared to MDD subjects with no further episodes during the follow-up interval.

Adolescent↗
PubMed1996

Epidermal growth factor protects mouse ileal mucosa from Triton X-100-induced injury.

Luminal exposure of mouse ileal mucosal sheets in vitro to 0.3% Triton X-100 for 10 min resulted in a 45.3 +/- 4.4% decrease in tissue resistance (Rt). Luminal pretreatment of tissue with epidermal growth factor (EGF, 30 nM) reduced the Triton X-100-induced decrease in Rt to 10.2 +/- 3.5%. This effect of luminal EGF was concentration-related with an A50 value of 7.4 nM. EGF applied to the basal buffer also produced a similar protective effect, but it was 5.3-fold less potent than luminal EGF. Morphological analysis indicated the formation of denudations at villi tips by Triton X-100 which was prevented by EGF pretreatment. These results suggest that EGF may play a role in the protection of ileal mucosal integrity.

Animals↗
PubMed1996

Effect of loading and fracture motions on diaphyseal tibial fractures.

A computerized motion sensor was used to record the three-dimensional components of interfragmentary motion during healing in three patients with closed, low-energy fractures of the tibial diaphysis treated with functional braces. At the first measurement session 2 weeks after fracture, the patients applied approximately 15 kg to the injured limb. Although this produced 1-4 mm of translation of the fragments, this was recovered when the load was removed. The maximum rotational and angulatory displacements often occurred as the patients rose from the chair with no weight applied to the limb and frequently were reduced as the 15 kg of load was applied. Under load, the maximum axial rotation was 3 degrees and the maximum angular displacement was 1 degree. As with the translations, the initial rotational and angulatory positions of the fragments were recovered when the load was removed and the patient returned to the seated position. At 8 weeks, the patient applied full body weight, producing a maximum interfragmentary translation of 0.5 mm and maximum axial rotation or angulation of 0.5 degrees. Abundant peripheral callus formed in all three fractures, and they healed by 15 weeks through typical gradual consolidation and mineralization of the callus, accompanied by a corresponding reduction in interfragmentary motions.

Adult↗
PubMed1996

Limiting dilution analysis of proliferating and cytotoxic lymphocytes in the peripheral blood and tumours of oral cancer patients.

Frequencies of proliferating and cytotoxic lymphocytes from the peripheral blood and tumour tissue of oral cancer patients and healthy individuals were monitored using limiting dilution analysis. Significantly lower precursor frequencies of proliferating lymphocytes were observed in the peripheral blood and tumour tissue of oral cancer patients. A high frequency of natural killer (NK) cells but low cytotoxic T lymphocytes (CTL) was observed in the peripheral blood compartment of oral cancer patients as compared to healthy individuals. A marked reduction in both NK and CTL frequencies in the tumour tissue compared to the peripheral blood was observed. In the tumour tissues, increased percentages of activated CD4+ lymphocytes as compared to CD8+ lymphocytes were observed. Our results suggest that impaired proliferative and cytotoxic potential of tumour infiltrating lymphocytes may play an important role in the escape of tumour cells from the immune system.

Adult↗
PubMed1996

Effects of granulocyte colony-stimulating factor in severe pancreatitis.

BACKGROUND: The effect of granulocyte colony-stimulating factor (G-CSF) on the rate of secondary infections in acute pancreatitis was evaluated in a canine model. Infectious complications are the major determinant of morbidity and mortality in severe pancreatitis. Bacterial translocation has been shown to be a cause of these secondary infections. The relative immunosuppression found with pancreatitis may promote translocation and the spread of bacteria to the pancreas. METHODS: Thirty-four mongrel dogs were studied. Pancreatitis was induced in 18 dogs; 9 were treated with 100 micrograms G-CSF/day and 9 were given only saline solution. Laparotomy alone was done in 16 dogs of which one half were given 100 micrograms G-CSF/day and one half were given saline solution. Daily blood counts and cultures were obtained. All dogs were killed on day 7, and the mesenteric lymph nodes, pancreas, liver, spleen, and peritoneal fluid were cultured and studied histologically. RESULTS: G-CSF caused a significant and sustained increase in mature granulocytes in dogs given pancreatitis. No difference was found in the rate of translocation to mesenteric lymph nodes in dogs given G-CSF (n = 4) versus dogs given saline solution (n = 6). However, a significant decrease occurred in the spread of bacteria to distant sites in dogs given G-CSF (1 versus 15, p < 0.05). CONCLUSIONS: Although G-CSF does not decrease the rate of translocation, it does decrease the rate of distant infection in severe acute pancreatitis.

Acute Disease↗