Search PubMed⌕ Search

Biomedical subjects

J Prasad

Publications and source records attributed to J Prasad.

At least 55 records · Page 3Linked to original sources
PubMed1986

Perennial allergic conjunctivitis: definition, clinical characteristics and prevalence. A comparison with seasonal allergic conjunctivitis.

Perennial allergic conjunctivitis (PAC) is a perennial form of seasonal allergic (hay fever) conjunctivitis (SAC). Fourteen subjects with PAC were compared with 25 subjects with SAC. All patients met the same criteria for the diagnosis of a Type 1 ocular allergy. In a study of ophthalmic morbidity at an inner city health centre during the summer months the 3-month period prevalence of PAC was 3.5:10,000. In PAC symptoms are present throughout the year although seasonal exacerbations occurred in 79 per cent. Many similarities were found with SAC. PAC showed the same age range, length of history and symptoms as SAC although SAC was more severe. In both, conjunctival cytology showed eosinophils (PAC 43 per cent; SAC 25 per cent) and total IgE levels were raised in the tears (PAC 100 per cent; SAC 96 per cent) and serum (PAC 79 per cent; SAC 78 per cent). However, PAC differed from SAC in several respects: a history of exacerbation on exposure to house dust (PAC 42 per cent; SAC none) and an association with perennial rhinitis (PAC 75 per cent; SAC 12 per cent) were more common in PAC. The largest response on skin prick testing to a panel of antigens was to house dust mite (Dermatophagoides pteronyssinus) and this was more frequent in PAC (PAC 71 per cent; SAC 4 per cent). Dust mite antigen specific IgE was present in the tears of 78 per cent of cases of PAC, in higher levels than in serum indicating local production of IgE, whereas in SAC there were no detectable levels in any of the tears tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Comparison of the ocular effects of atropine or glycopyrrolate with two I.V. induction agents.

Atropine and glycopyrrolate combined with either methohexitone or thiopentone were compared with the induction agent alone in patients undergoing electroconvulsive therapy. Patients acted as their own controls in each sub-group defined by induction agent. Pupil size, muscle twitches, presence of hiccups and the extent of oropharyngeal secretions were noted. Methohexitone produced a greater and more prolonged increase in pupil size than did thiopentone. The subsequent pupil size following the atropine-methohexitone mixture was significantly greater than that following the glycopyrrolate-methohexitone mixture. The combination of atropine with thiopentone produced a greater "secondary" mydriasis than thiopentone alone, or thiopentone combined with glycopyrrolate. The effect of the glycopyrrolate-thiopentone combination did not differ significantly from that of thiopentone alone. Methohexitone was associated with a greater incidence of hiccups, muscle twitching and excessive salivation.

Adult↗
PubMed1983

Status of hepatitis B virus in the aetiology of uveitis in Great Britain.

Viruses have been demonstrated or suspected as the causative agents of various types of uveitis. Hepatitis B virus (HBV), apart from causing hepatitis, has also been implicated in the pathogenesis of systemic vasculitis, for example in glomerulonephritis and polyarteritis nodosa. It is therefore possible to postulate that a similar vasculitic process might occur in the eye leading to intraocular inflammation. A recent report from Switzerland suggests that HBV may be implicated in the aetiology of uveitis, as hepatitis B surface antigen (HBsAg) was found in the serum of 13% of cases of uveitis. Since the status of HBV in the aetiology of uveitis in Great Britain has not been investigated, we have examined serum from 200 cases of uveitis of various clinical types for the presence of circulating HBsAg. Only 4 cases (2%) were found to be HBsAg positive. This study failed, therefore, to confirm HBV as an important cause of uveitis in this country, but one cannot exclude the possibility that it may play a pathogenetic role in a small proportion of such cases.

Adolescent↗
PubMed1981

Role of deep nephrons and the terminal collecting duct in a mannitol-induced diuresis.

Recollection micropuncture in Munich-Wistar rats was used to study the effects of intravenous hypertonic mannitol infusions on fluid reabsorption by surface nephrons, prior to the bend of Henle's loop of deep nephrons, and along the papillary collecting duct. During mannitol diuresis, single nephron glomerular filtration rate rose significantly in surface nephrons but fell in deep nephrons. Although mannitol increased the delivery of sodium and water to the end of the proximal tubule and to the first portion of the distal tubule of surface nephrons, water and sodium were reabsorbed between these two sites. In deep nephrons, water reabsorption prior to the bend of the loop of Henle was significantly decreased. Absolute sodium delivery to this site was reduced despite a marked decrease in fractional sodium reabsorption prior to the bend. Papillary osmolality was decreased. Renal plasma flow and inner medullary plasma flow (IMPF) increased proportionally. The reduced water extraction prior to the bend of deep nephrons and the decrease in papillary osmolality could have been partly due to a concomitant increase in IMPF and a decrease in sodium delivery to the medulla. The reabsorption of delivered sodium and water by the papillary collecting duct was reduced to a greater extent than could be expected from the increase in sodium delivery.

Absorption↗
PubMed1979

Response of deep nephrons and the terminal collecting duct to a reduction in renal mass.

Juxtamedullary (JM) nephron and collecting duct function was studied after a two-thirds reduction in renal mass in the young rat. The glomerular filtration rate of JM nephrons was twofold greater in the remnant kidney (RK) group than in controls, but this increase was proportional to the increase measured in surface nephrons. Despite an increase in absolute reabsorption, delivery of sodium and water to the end of the proximal tubule of superficial nephrons and to the bend of Henle's loop of JM nephrons was increased. This was a consequence of an increase in filtered load and a decrease in fractional reabsorption. Potassium handling in surface nephrons was similar to that of sodium and water. In deep nephrons of the RK group, potassium delivery to the bend was increased as a consequence of increased filtered load. The terminal portion of the collecting duct has a role in this adaptive response to a reduction in renal mass. In rats with a RK, reabsorption of water occurred along this segment; however, when the amount reabsorbed was related to delivery, fractional water reabsorption was only 30% of controls. Changes in sodium handling were more profound. In the group with the RK, sodium reabsorption was not detectable along this segment. Thus, while 40% of delivered sodium was reabsorbed in controls, in the remnant kidney group the mean was not different from zero (-1.7%).

Animals↗
PubMed1978

Deep nephron function after release of acute unilateral ureteral obstruction in the young rat.

The effects of acute unilateral ureteral obstruction (UUO) of 18 h duration on deep nephron function was evaluated in 14 weanling rats with the technique of micropuncture. After release of UUO, 3.4 +/- 0.66% (SE) of the filtered water remained at the tip of the collecting duct nearly fivefold greater than in controls (0.75 +/- 0.10%). Similar differences were seen in fractional sodium that remained at this site. The ratio of tubular fluid osmolality to that of plasma was also reduced in the UUO group (1.53 +/- 0.06 vs. 4.60 +/- 0.26 in controls, P less than 0.001). Single nephron glomerular filtration rate of cortical and deep nephrons was significantly less (P less than 0.001) after release of UUO. Although the percentage of filtering nephrons was significantly reduced in both nephron populations, the decline in glomerular filtration rate was greater in cortical than in juxtamedullary nephrons (cortical:juxtamedullary nephrons = 27.6 +/- 4.5% vs. 53.3 +/- 5.2% in controls, P less than 0.005) which suggests that single nephron glomerular filtration rate is redistributed to deep nephrons after release of UUO. In contrast to cortical nephrons, the amount of tubular fluid which remains near the bend of the loop of Henle of deep nephrons was greater after release of UUO. This appeared to be the result of a decrease in the reabsorption of both water (tubular fluid:plasma inulin = 2.41 +/- 0.16 vs. 7.94 +/- 0.69 in controls, P less than 0.001) and sodium (52.3 +/- 4% vs. 40.7 +/- 2.9% of the filtered sodium in controls, P less than 0.02). It is suggested that this altered reabsorption occurs along both the proximal tubule and descending limb of the loop of Henle of juxtamedullary nephrons. Inner medullary plasma flow (IMPF), as measured with the [125I]albumin-accumulation technique, was significantly depressed before release of UUO, but exceeded control values 90 min postrelease. Such changes imply that the filtration fraction of deep nephrons is decreased and that physical factors in the proximal tubular reabsorption of sodium have been altered. When papillary solute content was measured before release of UUO it was low (428 +/- 23 vs. 1,205 +/- 106 mosmol/kg in controls, P less than 0.001) which indicates that the decline in papillary osmolality is not a consequence of the increased IMPF seen after ureteral release, but rather precedes it. In fact, the decline in papillary osmolality may contribute to the increase in IMPF after release of UUO and to the decreased reabsorption of fluid along the descending limb of the loop of Henle.

Animals↗