Search PubMed⌕ Search

Biomedical subjects

J Katz

Publications and source records attributed to J Katz.

At least 19 recordsLinked to original sources
PubMed2007

Unilateral 6-hydroxydopamine lesion of dopamine neurons and subchronic L-DOPA administration in the adult rat alters the expression of the vesicular GABA transporter in different subsets of striatal neurons and in the substantia nigra, pars reticulata.

The loss of dopamine neurons combined or not with the subsequent administration of L-DOPA in patients with Parkinson's disease or in experimental models of the disease results in altered GABAergic signaling throughout the basal ganglia, including the striatum and the substantia nigra, pars reticulata. However, the molecular mechanisms involved in altered GABA neurotransmission remain poorly understood. In order to be released from synaptic vesicles, newly synthesized GABA is transported from the cytosol into synaptic vesicles by a vesicular GABA transporter. The objective of this study was to examine the hypothesis that expression of the vesicular GABA transporter (vGAT) is altered in the unilateral 6-hydroxydopamine model of Parkinson's disease. Our results provide evidence that a unilateral 6-hydroxydopamine lesion results in increased and decreased vGAT mRNA levels in striatopallidal and striatonigral neurons, respectively. These two subsets of neurons were identified by the co-expression or lack of co-expression of preproenkephalin, a marker of striatopallidal neurons, using double-labeling in situ hybridization histochemistry. Such changes occurred in the striatum ipsilateral to the 6-hydroxydopamine lesion and were paralleled by decreased vGAT protein levels in the substantia nigra, pars reticulate (SNr). On the other hand, the subchronic systemic administration of L-DOPA increased vGAT mRNA levels in preproenkephalin-negative neurons on the side ipsilateral and, to a lesser extent, the side contralateral to the 6-hydroxydopamine lesion. Systemic L-DOPA also increased vGAT protein levels in the ipsi- and contralateral SNr. As a whole, the results provide original evidence that vGAT expression is altered in the 6-hydroxydopamine model of Parkinson's disease. They also suggest that the behavioral effects induced by a subchronic administration of L-DOPA to 6-hydroxydopamine-lesioned rats involve an increase in the vesicular release of GABA by striatonigral neurons.

Animals↗
PubMed2006

Combined propofol sedation with sub-Tenon's lidocaine/mercaine infusion for strabismus surgery in adults.

AIMS: To evaluate the safety and efficacy of propofol sedation combined with sub-Tenon's anaesthesia for strabismus surgery in adults. METHODS: Thirty-two consecutive patients aged 31-85 years underwent strabismus surgery under general (n=16) or local (n=16) anaesthesia. In the local anaesthesia (study) group, sedation was induced with a loading dose of midazolam, fentanyl, and propofol, followed by continuous infusion of propofol, 3-6 mg/k/h to deep sedation. A nasal tube was inserted to prevent airway obstruction. Sub-Tenon's anaesthesia included infusion of a 3-4 ml mixture (50 : 50) of lidocaine 2%/mercaine 0.5%. General anaesthesia consisted of premedication with midazolam, followed by fentanyl, esmeron-bromate, propofol, and tracheal intubation. Duration of surgery and anaesthesia, intraoperative oculocardiac reflex and arrhythmias, time to discharge, postoperative pain, nausea and vomiting, and patient and surgeon satisfaction were evaluated. RESULTS: The local anaesthesia group had a significantly shorter operative and anaesthesia time, fewer episodes of oculocardiac reflex or arrythmia/bradycardia requiring treatment, fewer early or late episodes of nausea and vomiting, and less pain. The patients and surgeon in this group reported higher satisfaction. CONCLUSION: Propofol sedation with local sub-Tenon's injection of lidocaine/mercaine is recommended for the induction and maintenance of anaesthesia during unilateral or bilateral strabismus surgery in adults. The method is quick and effective, without systemic or ocular side effects.

Adult↗
PubMed2006

Epidemiology of anemia among 4- to 17-month-old children living in south central Nepal.

OBJECTIVE: To describe the distribution of hemoglobin and prevalence of anemia in Nepali children living in the Terai region by potential risk factors for deficiency. DESIGN: This was a cross-sectional, community-based study of baseline characteristics of children enrolled in a randomized, placebo-controlled clinical trial between January and March 2002. Participants were weighed and measured and had their blood drawn. Their mothers contributed demographic, morbidity, and feeding data. SUBJECTS: There were 569 4- to 17-month-old children. Statistical models were based on 490 children. RESULTS: Anemia was prevalent: 58% of the children had a hemoglobin <105 g/l. Iron-deficiency anemia (anemia with erythrocyte protoporphyrin (EP) > or =90 micromol/mol heme) was present in 43% of the children. Severe anemia was rare: less than 2% of the children had a hemoglobin <70 g/l. The mean (s.d.) hemoglobin concentration was 101 (12.5) g/l. Stunting and wasting were prevalent: 30.8% were stunted (length-for-age Z-score <-2) and 18.1% were wasted (weight-for-length Z-score <-2). Bivariate analyses revealed that age, caste, socioeconomic status, dietary diversity, stunting, and underweight were associated with hemoglobin concentration and/or anemia. In multivariate models with and without EP, age and caste were found to be strong predictors of both hemoglobin concentration and anemia. CONCLUSIONS: Anemia and iron deficiency increased strongly with age and low-caste status among the study children. The data reveal the importance of targeting interventions to children in the first year of life before they become anemic and iron deficient.

Age Factors↗
PubMed2005

Single subject pharmacological-MRI (phMRI) study: modulation of brain activity of psoriatic arthritis pain by cyclooxygenase-2 inhibitor.

We use fMRI to examine brain activity for pain elicited by palpating joints in a single patient suffering from psoriatic arthritis. Changes in these responses are documented when the patient ingested a single dose of a selective cyclooxygenase-2 inhibitor (COX-2i). We show that mechanical stimulation of the painful joints exhibited a cortical activity pattern similar to that reported for acute pain, with activity primarily localized to the thalamus, insular, primary and secondary somatosensory cortices and the mid anterior cingulum. COX-2i resulted in significant decreased in reported pain intensity and in brain activity after 1 hour of administration. The anterior insula and SII correlated with pain intensity, however no central activation site for the drug was detected. We demonstrate the similarity of the activation pattern for palpating painful joints to brain activity in normal subjects in response to thermal painful stimuli, by performing a spatial conjunction analysis between these maps, where overlap is observed in the insula, thalamus, secondary somatosensory cortex, and anterior cingulate. The results demonstrate that one can study effects of pharmacological manipulations in a single subject where the brain activity for a clinical condition is delineated and its modulation by COX-2i demonstrated. This approach may have diagnostic and prognostic utility.

Adult↗
PubMed2005

Development of clinical sign based algorithms for community based assessment of omphalitis.

BACKGROUND: In developing countries, newborn omphalitis contributes significantly to morbidity and mortality. Community based identification and management of omphalitis will require standardised clinical sign based definitions. OBJECTIVE: To identify optimal sign based algorithms to define omphalitis in the community and to evaluate the reliability and validity of cord assessments by non-specialist health workers for clinical signs of omphalitis. DESIGN: Within a trial of the impact of topical antiseptics on umbilical cord infection in rural Nepal, digital images of the umbilical cord were collected. Workers responsible for in-home examinations of the umbilical cord evaluated the images for signs of infection (pus, redness, swelling). Intraworker and interworker agreement was evaluated, and sensitivity and specificity compared with a physician generated gold standard ranking were estimated. RESULTS: Sensitivity and specificity of worker evaluations were high for pus (90% and 96% respectively) and moderate for redness (57% and 95% respectively). Swelling was the least reliably identified sign. Measures of observer agreement were similar to that previously recorded between experts evaluating subjective skin conditions. A composite definition for omphalitis that combined pus and redness without regard to swelling was the most sensitive and specific. CONCLUSIONS: Two sign based algorithms for defining omphalitis are recommended for use in the community. Focusing on redness extending to the skin around the base of the stump will identify cases of moderate and high severity. Requiring both the presence of pus and redness will result in a definition with very high specificity and moderate to high sensitivity.

Algorithms↗
PubMed2005

Comparative effects of acute or chronic administration of levodopa to 6-hydroxydopamine-lesioned rats on the expression of glutamic acid decarboxylase in the neostriatum and GABAA receptors subunits in the substantia nigra, pars reticulata.

Current evidence suggests that behavioral sensitization to the chronic administration of levodopa (L-DOPA) to dopamine-depleted animals involves a plasticity of GABA-mediated signaling in output regions of the basal ganglia. The purpose of this study was to compare in adult rats with a unilateral 6-hydroxydopamine (6-OHDA) lesion the effects of an acute or chronic (for 3 or 7 days) injection of L-DOPA on mRNA levels encoding for glutamic acid decarboxylase (GAD65 and GAD67) in the striatum and GABA(A) receptor alpha1, beta2 and gamma2 subunits in the substantia nigra, pars reticulata (SNr), by in situ hybridization histochemistry. In addition, immunostaining levels for the alpha1 subunit were examined in the SNr. In agreement with previous studies, we found that L-DOPA administration increased GAD mRNA levels in the striatum of 6-OHDA-lesioned rats. However, the magnitude of this effect increased with the number of injections of L-DOPA. On the other hand, we found that 6-OHDA lesions resulted in increases in alpha1, beta2 and gamma2 mRNA levels in the ipsilateral SNr, which were normalized or decreased compared with the contralateral side by the acute or chronic administration of L-DOPA. In addition, alpha1 immunostaining in the SNr was significantly decreased in rats injected for 7 days but not for 3 days or acutely with L-DOPA. Our results demonstrate that a chronic administration of L-DOPA results in a progressive increase in GAD and decrease in GABA(A) receptor expression in the striatum and SNr, respectively. They provide further evidence that behavioral sensitization and dyskinesia induced by a chronic administration of L-DOPA in an experimental model of Parkinson's disease is paralleled by a plasticity of GABA-mediated signaling in the SNr.

Adrenergic Agents↗
PubMed2005

Expression of the receptor of advanced glycation end products in gingival tissues of type 2 diabetes patients with chronic periodontal disease: a study utilizing immunohistochemistry and RT-PCR.

OBJECTIVES: Relationship between diabetes and periodontal disease is well established. It has been shown that advanced glycation end-products (AGEs) might exert noxious effects on gingival tissues through its receptor. Evidence for the role of receptors of AGE (RAGE) in periodontal disease was verified in a murine model for diabetes. However, the presence of RAGE in human gingival tissues has not been demonstrated previously. In this study we demonstrate the presence of RAGE in human periodontium in patients with chronic periodontitis with and without type 2 diabetes. MATERIAL AND METHODS: Gingival biopsies from eight patients with both type 2 diabetes and chronic periodontitis and 14 healthy control subjects with chronic periodontitis were immunohistochemically stained for RAGE. Five samples from the study groups and four controls were subjected to reverse transcriptase coupled to polymerase chain reaction (RT-PCR) for quantitative determination of mRNA for RAGE. RESULTS: On immunohistochemistry, positive staining for RAGE was seen in the endothelium and the basal and spinous layer of the inflamed gingival epithelium in both type 2 diabetes and non-diabetes tissue with no statistically significant difference between both groups. RT-PCR, however, showed a 50% increase in mRNA for RAGE in the gingiva of diabetic patients when compared with controls (p<0.05). CONCLUSIONS: Although there was no change in the staining intensity for RAGE between both groups, the increase in the mRNA for RAGE in the type 2 diabetes gingival epithelium may indicate a possible involvement of this receptor in the periodontal destruction in type 2 diabetes.

Chronic Disease↗
PubMed2004

Peripheral odontogenic tumours--differential diagnosis in gingival lesions.

Peripheral odontogenic tumours (POT) are rare benign focal overgrowths of the oral soft tissue, usually occurring in the gingiva. Between 1996-2000, 6 out of 406 excised gingival lesions were diagnosed as POT (1.5%). Tumours included peripheral odontogenic fibroma (2 patients), peripheral calcifying odontogenic cyst (2 patients), peripheral ameloblastoma (1 patient), and peripheral calcifying epithelial odontogenic tumour (1 patient). Review of the literature reveals that peripheral odontogenic fibroma and peripheral ameloblastoma were the most common POT. The purpose of this article was to analyse the clinical data of these tumours according to the presented cases and the literature review, to elucidate typical features of each tumour type and enhance easy identification.

Adolescent↗
PubMed2004

Cigarette smoking during pregnancy in rural Nepal. Risk factors and effects of beta-carotene and vitamin A supplementation.

OBJECTIVE: We examined risk factors of smoking and the association between smoking and pregnancy-related and 6-month infant mortality in rural Nepal, where 30% women reported smoking during pregnancy. DESIGN: Cross-sectional analysis of risk factors associated with smoking status and health consequences of smoking, using prospective data collected as part of a randomized community trial to examine the effect of maternal vitamin A or beta-carotene supplementation on maternal mortality. SETTING: Rural, southeastern plains of Nepal. SUBJECTS AND METHODS: A total of 17 767 women contributed at least one pregnancy during 3.5 y of the study. Data on cigarette or bidi (rolled tobacco) smoking were collected using a 7-day recall, twice during pregnancy. Associations between smoking status and maternal diet, morbidity profile, household socioeconomic status and serum concentration of retinol, carotenoids and tocopherols were examined. Further, relative risk (RR) and 95% confidence intervals (CI) were calculated to estimate supplement effects on pregnancy-related mortality, stratified by smoking status during pregnancy. RESULTS: Smokers were more likely to be older, illiterate and poor compared to nonsmokers. Fruit and vegetable consumption among smokers and nonsmokers did not vary. However, smokers were more likely to consume meat/fish/eggs and less likely to consume milk than nonsmokers. They were also more likely to report symptoms of vaginal bleeding, edema, severe headache and convulsions during pregnancy relative to nonsmokers. Mortality per 100,000 pregnancies appeared to be higher among smokers than nonsmokers in the placebo group (915 vs 584, RR=1.57, 95% CI: 0.80-3.08). beta-Carotene supplementation reduced pregnancy-related mortality both among smokers (RR=0.31 95% CI: 0.11-0.89) and nonsmokers (RR=0.41, 95% CI: 0.19-0.89). Similar results obtained with vitamin A supplementation were not statistically significant. Infant mortality up to 6 months was approximately 30% higher among smokers compared to nonsmokers in the placebo group both before and after adjusting for confounding factors. Neither supplement given to women reduced infant mortality. CONCLUSIONS: Cigarette smoking during pregnancy is associated with an increased risk of maternal and infant mortality in rural Nepal. beta-Carotene and to some extent vitamin A may reduce the risk of pregnancy-related mortality, but not infant mortality, among both smokers and nonsmokers.

Adult↗
PubMed2004

Receptor of advanced glycation end product (RAGE) expression in the minor salivary glands of patients with Sjögren's syndrome: a preliminary study.

OBJECTIVE: Receptor for advanced glycation end product (RAGE) is a cell-surface receptor with ligands capable of inducing proinflammatory responses in autoimmunity. We investigated the immunohistochemical expression and immunoblotting of RAGE in labial salivary glands from Sjögren's syndrome (SS) patients. MATERIAL AND METHODS: Ten minor salivary glands from SS and 15 from normal salivary tissue adjacent to mucocele were stained immunohistochemically using an antibody to RAGE. Immunoblotting was performed on four SS biopsies and four controls from normal gland. RESULTS: Immunohistochemistry showed all sections positive for RAGE. The SS sections did not statistically differ from controls. In immunoblotting, SS samples expressed approximately 100% more RAGE than controls [probability (p)<0.03, Student's t-test]. CONCLUSIONS: RAGE is present in the labial salivary glands of both normal and SS patients, with preliminary data suggesting over-expression in SS tissues. The role of RAGE in the pathogenesis of SS has yet to be determined.

Aged↗
PubMed2004

A randomised, controlled study of peri-operative low dose s(+)-ketamine in combination with postoperative patient-controlled s(+)-ketamine and morphine after radical prostatectomy.

In a randomised, double-blind prospective study we compared the effects on postoperative pain and analgesic consumption of intra-operative s(+)-ketamine (100 microg.kg-1 bolus and a continuous infusion of 2 microg.kg-1.min-1) followed by postoperative patient-controlled analgesia with morphine (1 mg per bolus) plus s(+)-ketamine (0.5 mg per bolus), or intra-operative saline followed by postoperative patient-controlled analgesia morphine (1 mg per bolus) alone. A total of 28 male patients undergoing radical prostatectomy were studied. Morphine consumption, pain scores, pressure algometry and adverse effects were recorded for 48 h after surgery. Cumulative morphine consumption was significantly lower in the ketamine/morphine group (47.9 +/- 26.2 mg) than in the saline/morphine group (73.4 +/- 34.8 mg; p = 0.049). Pain scores at rest were significantly lower in the ketamine/morphine group across the 48-h study period (p = 0.01). No significant differences were found in pressure algometry measurements or the occurrence of adverse effects.

Adult↗
PubMed2004

The relation between birth size and the results of refractive error and biometry measurements in children.

AIM: To examine the association of birth parameters with biometry and refraction in Singapore Chinese schoolchildren. METHODS: Chinese children aged 7-9 years (n = 1413) from three schools in Singapore were recruited. Birth parameter information on birth weight, head circumference, length at birth, and gestational age were obtained from standard hospital records. Cycloplegic autorefraction, keratometry and biometry measures (axial length, vitreous chamber depth, lens thickness, and anterior chamber depth) were obtained. RESULTS: Across the normal birthweight range (2.0-4.9 kg), children with birth weights > or =4.0 kg had longer axial lengths (adjusted mean 23.65 mm versus 23.16 mm), compared with children with birth weights <2.5 kg, after controlling for age, sex, school, height, parental myopia, and gestational age. For every 1 cm increment in head circumference at birth, the axial length was longer by 0.05 mm. For every 1 cm increment in birth length, the axial length was longer by 0.02 mm in multivariate analysis. Additional week increases in gestational age till 46 weeks resulted in axial lengths that were longer by 0.04 mm, controlling for age, sex, school, parental myopia, and height. Children with larger birth weights, head circumferences, birth lengths, or gestational ages had deeper vitreous chambers and larger corneal curvature radii; however, there were no significant associations with refraction. CONCLUSIONS: Children who were born heavier, had larger head sizes or lengths at birth, or who were born more mature had longer axial lengths, and deeper vitreous chambers; but there were no differences in refraction at ages 7-9 years, possibly because of the observed compensatory flattening of the cornea.

Anterior Chamber↗
PubMed2004

The epidemiology of ocular trauma in rural Nepal.

AIMS: To estimate the incidence of ocular injury in rural Nepal and identify details about these injuries that predict poor visual outcome. METHODS: Reports of ocular trauma were collected from 1995 through 2000 from patients presenting to the only eye care clinic in Sarlahi district, Nepal. Patients were given a standard free eye examination and interviewed about the context of their injury. Follow up examination was performed 2-4 months after the initial injury. RESULTS: 525 cases of incident ocular injury were reported, with a mean age of 28 years. Using census data, the incidence was 0.65 per 1000 males per year, and 0.38 per 1000 females per year. The most common types of injury were lacerating and blunt, with the majority occurring at home or in the fields. Upon presentation to the clinic, 26.4% of patients had a best corrected visual acuity worse than 20/60 in the injured eye, while 9.6% had visual acuity worse than 20/400. 82% were examined at follow up: 11.2% of patients had visual acuity worse than 20/60 and 4.6% had vision worse than 20/400. A poor visual outcome was associated with increased age, care sought at a site other than the eye clinic, and severe injury. 3% of patients were referred for further care at an eye hospital at the initial visit; 7% had sought additional care in the interim between visits, with this subset representing a more severe spectrum of injuries. CONCLUSIONS: The detrimental effects of delayed care or care outside of the specialty eye clinic may reflect geographic or economic barriers to care. For optimal visual outcomes, patients who are injured in a rural setting should recognise the injury and seek early care at a specialty eye care facility. Findings from our study suggest that trained non-ophthalmologists may be able to clinically manage many eye injuries encountered in a rural setting in the "developing" world, reducing the demand for acute services of ophthalmologists in remote locations of this highly agricultural country.

Accidents, Home↗
PubMed2004

Risk factors for age related cataract in a rural population of southern India: the Aravind Comprehensive Eye Study.

AIM: To determine risk factors for lens opacities and age related cataract in an older rural population of southern India. METHODS: A cross sectional population based study of 5150 people aged 40 years and above from 50 clusters from three districts in southern India. The lens was graded and classified after dilation using LOCS III system at the slit lamp for cataract. Definite cataract was defined as nuclear opalescence >/=3.0 and/or cortical cataract >/=3.0 and/or PSC >/=2.0. RESULTS: Definite cataracts were found in 2449 (47.5%) of 5150 subjects and the prevalence of cataract increased with age. The age adjusted prevalence of cataract was significantly lower in males (p = 0.0002). Demographic risk factors-increasing age and illiteracy-were common for the three subtypes of cataract; females were more likely to have cortical cataracts and nuclear cataracts. Additionally, nuclear cataracts were associated with moderate smoking (OR:1.28, 95% CI:1.01 to 1.64), lean body mass indices (OR: 1.37, 95% CI: 1.17 to 1.59) and higher waist to hip ratios (OR: 0.67, 95% CI: 0.54 to 0.82); cortical cataracts with hypertension (OR: 1.39 95% CI:1.11 to 1.72), pseudoexfoliation (OR:1.53,95% CI:1.17 to 2.01), and moderate to heavy smoking; and posterior subcapsular cataracts with diabetes (OR:1.55, 95% CI:1.12 to 2.15), lean body mass (OR:1.32, 95% CI:1.11 to 1.57), and high waist to hip ratios (OR: 0.77, 95% CI: 0.62 to 0.94). CONCLUSIONS: Risk factors for age related cataract in this population do not appear to be different from those reported in other populations. Further studies are required to identify the reason for the high prevalence of age related cataract and to understand better the role of each risk factor for cataractogenesis in this population.

Adult↗
PubMed2004

Utilisation of eye care services in rural south India: the Aravind Comprehensive Eye Survey.

AIM: To determine utilisation of eye care services in a rural population of southern India aged 40 years or older. METHODS: 5150 subjects aged 40 years and older selected through a random cluster sampling technique from three districts in southern India underwent detailed ocular examinations for vision impairment, blindness, and ocular morbidity. Information regarding previous use of eye care services was collected from this population through a questionnaire administered by trained social workers before ocular examinations. RESULTS: 3476 (72.7%) of 5150 subjects examined required eye care examinations. 1827 (35.5%) people gave a history of previous eye examinations, primarily from a general hospital (n = 1073, 58.7%). Increasing age and education were associated with increased utilisation of eye care services. Among the 3323 people who had never sought eye care, 912 (27.4%) had felt the need to have an eye examination but did not do so. Only one third of individuals with vision impairment, cataracts, refractive errors, and glaucoma had previously utilised services. CONCLUSIONS: A large proportion of people in a rural population of southern India who require eye care are currently not utilising existing eye care services. Improved strategies to improve uptake of services is required to reduce the huge burden of vision impairment in India.

Adult↗