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Biomedical subjects

V Joseph

Publications and source records attributed to V Joseph.

18 recordsLinked to original sources
PubMed2006

Developmental pattern of M1 and M2 muscarinic gene expression and receptor levels in cat carotid body, petrosal and superior cervical ganglion.

Using real-time reverse transcriptase polymerase chain reaction, Northern blot, and Western blot analyses, we evaluated the developmental pattern of mRNA and protein expression level of muscarinic M1 and M2 receptors in the carotid body, petrosal ganglion and superior cervical ganglion of 1-day, 15-day, 2-month-old and adult cats. mRNA expression and protein levels of tyrosine hydroxylase, the rate limiting enzyme for dopamine synthesis, were also assessed. Carotid body M1 receptor mRNA, increased significantly by approximately 100% and 300% in 2-month and adult vs. 1- and 15-day-old cats, but protein level decreased gradually being approximately 50% lower compared with 1-day-old cats. In the petrosal ganglion, muscarinic M1 receptor mRNA level was higher in 15-day-old cats vs. 1-day-old, 2-month-old and adult cats and protein levels were about 30% lower than in 1- and 15-day-old cats. In the superior cervical ganglion, muscarinic M1 receptor mRNA was approximately 50% and 80% higher in 2-month-old and adult cats than 1- and 15-day-old, but no changes in the protein level except in 15-day-old cats which was approximately 40% higher than 1-day-old. There was no change of muscarinic M2 receptor mRNA or protein level in the carotid body or petrosal ganglion. However, in the superior cervical ganglion, the significant increase of mRNA of 30% and 50% in 2-month-olds and adults, respectively was not associated with an increase in receptor protein. Tyrosine hydroxylase mRNA and protein level decreased significantly with age in the carotid body and petrosal ganglion. In the superior cervical ganglion, the age dependent increase in tyrosine hydroxylase mRNA was not associated with any changes in the protein level. These results show that the expression of muscarinic M1 and M2 receptors are age and organ-dependent in cats. Consequently, these changes may modulate chemosensory activity during development since muscarinic M1 receptor is predominantly involved in postsynaptic chemosensory activity, while muscarinic M2 receptor modulates acetylcholine and dopamine release from chemosensitive cells.

Age Factors↗
PubMed2005

Perinatal steroid exposure and respiratory control during early postnatal life.

Numerous factors involved in general homeostasis are able to modulate respiratory motor output. These include placental-derived steroids, which are necessary for maternal physiological adjustments during gestation, including respiratory stimulation. Despite the fact that these hormones exert potent effects on neural development in the fetus, the hypothesis of a developmental control of the neural respiratory network by placental-derived steroids has been approached experimentally only recently. The objective of this review is to summarize the role and mode of action of placental steroids on respiratory control in adult mammals and highlight the potential pathways by which such steroids are supplied to the developing fetus. Additionally, we present recent results showing that the beta estradiol and progesterone receptors are expressed in the carotid body of newborn male rats, thus supporting the hypothesis of receptor-mediated effect of estradiol and progesterone on carotid bodies.

Animals↗
PubMed2005

Suprabrow minicraniotomy for suprasellar tumours.

We present our experience with suprabow minicraniotomy in the excision of 18 suprasellar tumours between May 2001 and September 2003. There were 14 females and four males with ages ranging from 7 to 59 years. The tumours included one epidermoid cyst, 10 meningiomas, five craniopharyngiomas and two optico-chiasmatico-hypothalamic (OCHG) gliomas. The size of the one-piece craniotomy was about 2.5 cm. Both OCHGs were biopsied; one craniopharyngioma was totally excised, the remaining craniopharyngiomas and epidermoid cyst were subtotally excised. Four meningiomas were radically excised and six were subtotally removed. The patient with a craniopharyngioma that had a radical excision died of hypothalamic dysfunction. One patient developed a postoperative meningitis and subsequent hydrocephalus requiring a shunt. The other patients did well and the cosmetic result was excellent in all cases. This basal approach through a small craniotomy provided good surgical access to suprasellar tumours with minimal brain retraction.

Adolescent↗
PubMed2004

Prenatal blockade of estradiol synthesis impairs respiratory and metabolic responses to hypoxia in newborn and adult rats.

We tested the hypothesis that estradiol modifies respiratory control in pregnant rats and participates in the development of respiratory chemoreflexes in fetuses. Pregnant rats (n = 12) received daily subcutaneous injections of vehicle (Veh, n = 6) or 4-androsten-4-ol-3,17-dione acetate (ATD; inhibitor of estradiol synthesis; n = 6; 5 mg/day in vehicle) from gestational day 16 (G16) to delivery. Baseline ventilation (whole body plethysmography) and metabolic rate [oxygen consumption (Vo(2))] were determined at G14 and G20, in pups [on postnatal day 3 (P3) and P20] and in adult rats (on P70) born to Veh- or ATD-treated mothers. Hypoxic chemoreflex was assessed in P3 rats by acute exposure to 60% O(2) and in P20 or P70 rats by moderate hypoxia (12% O(2), 30 min). ATD treatment reduced circulating estradiol in pregnant dams at G20 without producing changes in the circulating level of estradiol precursors (testosterone and androstenedione). ATD-treated dams showed impaired respiratory adjustment to late gestation. Pups born to ATD mothers had higher resting Vo(2) (+23% at P3, +21% at P20), respiratory frequency (+15% at P3, +12% at P20), and minute ventilation (+11% at P3, +18% at P20) than pups from Veh mothers. Respiratory decrease during acute hyperoxic exposure at P3 was -9.7% in Veh (P < 0.05 vs. room air) and only -2.6% (P = not significant) in ATD pups. In P20 ATD rats, hypoxic ventilatory response was attenuated compared with Veh. In P20 and P70 rats, the drop of Vo(2) in hypoxia (-31% in P70, P < 0.0001) was not observed in ATD rats. We conclude that estradiol secreted during late gestation is necessary for respiratory adjustment to pregnancy and is required for adequate development of respiratory and metabolic control in the offspring.

Adaptation, Physiological↗
PubMed2004

A zone-wise ecological-economic analysis of Indian wetlands.

In view of their sensitivity and importance, an ecological-economic analysis of wetlands has been carried out for various Indian states. Subsequently, the ecological wealths of different zones (north, south, east and west) have been computed and compared. Amongst states, Karnataka (7896.5 million US dollars yr(-1)), Gujarat (7689.4 million US dollars yr(-1)) and Andhra Pradesh (7670.9 million US dollars yr(-1)) are found to be the richest, whereas Nagaland (3.1 million US dollars yr(-1)), Meghalaya (5.9 million US dollars yr(-1)) and Sikkim (15.9 million US dollars yr(-1)) turn out to be the poorest. Amongst different zones, Southern Zone turns out to be the richest and the Northern Zone poorest. A ratio called ANR [Artificial (A) Wetland Wealth to Natural (N) Wetland Wealth Ratio (R)] has also been devised, which is the ratio of the ecological-economic values of artificial and natural wetlands. In other words, this ratio indicates the level of environmental concern of a given region. ANR ratio is found to be the highest for Madhya Pradesh (564.1) and Karnataka (159.8) states.

Conservation of Natural Resources↗
PubMed2002

Aerosol scavenging: model application and sensitivity analysis in the Indian context.

Sulfate aerosols have been found to be the major contributors to precipitation acidity. Thus, in view of the long-term ecological repercussions they have on aquatic ecosystems and their acidity-potential, the present analysis focuses on a case study application of the layer-averaged aerosol-scavenging model (Okita et al., 1996) for predicting values of the wet scavenging coefficient and sulfate concentrations in precipitation samples on the basis of the information available for some selected Indian cities. Through sensitivity analysis (Pandey et al., 1997) the scavenging coefficient has been found to be very strongly dependent on precipitation intensity. Comparison of model predictions has been done with the measured values for Delhi, Mumbai, Calcutta and Chennai in India.

Acid Rain↗
PubMed2001

Viability of water weeds and microalga in pulp and paper mill wastewater.

Water weeds Azolla pinnata and Lemna minor and the chlorophycean alga Scendesmus bijugatus were grown in a paper mill wastewater. The objective of the study was to assess the viability of these species upon exposure to such effluents and to assess their potential in the improvement of effluent quality. The wastewater was analysed before and after the treatment with these species. The growth of the alga and the hydrophytes was also measured. The algal assay revealed that the clear effluent will promote algal growth on addition of fertilizer while water weeds did not require fertilizer input. Both the algae and macrophytes could reduce the BOD and COD of the effluent.

Araceae↗
PubMed2000

Gender differentiation of the chemoreflex during growth at high altitude: functional and neurochemical studies.

The effect of chronic hypoxia on gender differences in physiology and neurochemistry of chemosensory pathways was studied in prepubertal and adult rats living at sea level (SL; Lyon, France) or at high altitude (HA; La Paz, Bolivia, 3,600 m). HA adult rats had higher hematocrit (Ht%), Hb concentration, resting ventilatory rate (Ve(100)), and higher tyrosine hydroxylase (TH) activity in carotid bodies (CB) than SL animals. At HA and SL, adult females had lower Ht% (46.0 +/- 0.8 vs. 50.4 +/- 0.6% at HA, P < 0.05 and 43.8 +/- 0.9 vs. 47.1 +/- 0.8% at SL, P < 0.05) and Hb (16.1 +/- 0.3 vs. 17.7 +/- 0.2 g/dl at HA, P < 0.05 and 14.5 +/- 0.3 vs. 15.6 +/- 0.1 g/dl at SL, P < 0.05) than males. Females had higher Ve(100) [170 +/- 19 vs. 109 +/- 7 ml. min(-1). 100 g(-1) at HA, P < 0.05 and 50 +/- 3 vs. 40 +/- 2 ml. min(-1). 100 g(-1) at SL, not significant (NS)] and lower CB-TH activity (1.40 +/- 0.2 vs. 3.87 +/- 0.6 pmol/20 min at HA, P < 0.05 and 0.52 +/- 0.1 vs. 0.68 +/- 0.1 pmol/20 min at SL; NS) than males at HA only. The onset of hypoxic ventilatory response during development was delayed at HA. Prepubertal HA females had higher Ve(100) than males (2 wk old, +47%) and higher CB-TH activity (3 wk old, +51%). Medullary noradrenergic groups were sex dimorphic during development at SL. Rats raised at HA had a drop of TH activity between the second and the third postnatal week in all medullary groups. In conclusion, our data support the hypothesis that the CB is the major site for sexual differentiation of the ventilatory control. Ventilatory differences appeared before puberty, and the animals bred at HA had profound alterations in the developmental process of the chemoreflex and its neural pathways. Some of these alterations are under dependence of the sex of the animal, and there is an important interaction between gender and the hypoxic environmental condition during the developmental period.

Age Factors↗
PubMed1999

Raptor hematology and chemistry evaluation.

Hematologic and biochemical evaluation of raptor blood samples is discussed to guide the practitioner in the diagnosis of disease. Species and age variation in the raptors in response to the laboratory values is also addressed.

Animals↗
PubMed1999

Introducing Adelaide dental students to a problem-based learning curriculum.

A course designed to introduce new students to a problem-based learning (PBL) curriculum in dentistry at the University of Adelaide is described. Australian students are admitted to the Adelaide dental course either directly from school (SL) or after one or more years of tertiary education (TT). The admissions process is designed to select academically able students who will flourish in a problem-based environment. Some international students (INT) are also selected through a modified admissions process. A 9-item questionnaire derived from frequently-asked questions from previous years was administered to the new students at the beginning and at the end of the introductory course, and each individual's responses before and after the course were compared. There was an increased number of positive responses (significant at P < 0.05 to 7 of the 9 items) after the course. Although the course appeared to be effective in familiarising new students with a PBL curriculum, many students were still uncertain about two items which commonly provoke anxiety, namely how to decide when to stop researching a topic, and how to balance group and solo learning.

Attitude of Health Personnel↗
PubMed1998

Dexamethasone's influence on tyrosine hydroxylase activity in the chemoreflex pathway and on the hypoxic ventilatory response.

Catecholamines have been implicated in neuromodulation of peripheral chemosensitivity and central respiratory mechanisms. Because glucocorticoids can affect catecholamine metabolism in the carotid body and brainstem, this study explored the possibility that, in rats, dexamethasone or adrenalectomy affects catecholamine biosynthesis in carotid body chemoreceptors and the medullary areas (A2C2, A5, A6, A7) involved in the chemoreflex pathway and the hypoxic ventilatory response (HVR). One dexamethasone injection (1 mg/kg body wt.) stimulated tyrosine hydroxylase activity in the carotid body and had no effect in brainstem catecholamine areas, while HVR was reduced. Chronic dexamethasone (1 mg/kg body wt. daily for 10 days) had a stimulatory influence on tyrosine hydroxylase activity in the carotid body and an inhibitory effect on A2C2, A5 and A7 cell groups. Breathing pattern, but not HVR, was altered. Adrenalectomy elicited an increase in tyrosine hydroxylase activity in A2C2, which was accompanied by a decreased respiratory frequency in hypoxia. The data show that glucocorticoids have differential effects on catecholamine biosynthesis in peripheral and central structures involved in the chemoreflex pathway. Depending on the treatment, the neurochemical changes were accompanied by alterations of HVR or the breathing pattern, which are consistent with a neuromodulating influence of catecholamines on peripheral chemosensory inputs or the central respiratory network.

Adrenalectomy↗
PubMed1998

Emergency care of raptors.

Emergency care of raptors often requires extensive diagnostics and therapeutic regimens to stabilize and support the ill or injured raptor. Whether falconry birds, educational birds, or raptors from the wild are presented, various medical conditions must be addressed to help guide the practitioner toward a complete recovery for the raptor.

Animal Husbandry↗
PubMedDate not supplied

Atypical parasitic migration and necrotizing sacral myelitis due to Serratospiculoides amaculata in a prairie falcon (Falco mexicanus).

An adult, wild-caught, female prairie falcon (Falco mexicanus) was presented with the chief complaint of anorexia. Radiographic findings included increased densities within the air sacs, and coelomic endoscopy revealed numerous slender worms within the air sacs and on the serosal surfaces of the ovary, oviduct, liver, proventriculus, and ventriculus. The bird seemed to improve for a short period of time with antiparasitic therapy (ivermectin and fenbendazole) and supportive care. Twenty-one days after initial presentation, the bird became recumbent with increasing pelvic limb neurologic deficits and was euthanized. On histopathologic examination, mature nematodes and larvated eggs identified as Serratospiculoides amaculata were found within the subdural space of the distal thoracolumbar and synsacral spinal cord and within the coelomic cavity. This case suggests that S. amaculata can cause clinically significant lesions in its falconiform host with potentially fatal results.

Animals↗