Effect of eye rubbing on signs and symptoms of allergic conjunctivitis in cat-sensitive individuals.

OBJECTIVE: To evaluate the effect of eye rubbing on signs and symptoms of allergic conjunctivitis in cat-sensitive individuals. DESIGN: Two prospective, nonrandomized comparative studies. PARTICIPANTS: Thirteen patients in the first study and 20 patients in the second study with a documented history of acute allergic conjunctivitis induced by exposure to cats were enrolled. INTERVENTION: In the first trial, all patients had one eye rubbed 15 times by the investigator without exposure to airborne allergens. Both eyes were evaluated after 5, 15, 30, and 60 minutes using subject questionnaires and slit-lamp examination. At least 1 week later, each patient was exposed to cat dander for 75 minutes; 15 minutes after entering the cat room, each patient had one eye rubbed 15 times by the examiner. Subjects' eyes were then evaluated using questionnaires and slit-lamp examination. In the second trial, the visits were identical to the first trial, except that the rubbed eye in each visit was rubbed 20 times and with more force, and that patients wore masks during exposure to cat dander. MAIN OUTCOME MEASURES: In both studies, the difference between patients' rubbed and nonrubbed eyes with respect to ocular itching, chemosis, and hyperemia was noted 5, 15, 30, and 60 minutes after controlled eye rubbing. RESULTS: Without exposure to the cat room, rubbed eyes exhibited increased itching at 5 minutes in both studies and at 15 minutes in the second study (P < 0.05), increased chemosis at 5 and 15 minutes in the second study (P < 0.05), and increased hyperemia at 5 minutes in the second study (P < 0.05) compared with nonrubbed eyes. During exposure to cat dander, rubbed eyes consistently exhibited increased itching at 5, 15, and 30 minutes in the first and second study as well as at 60 minutes in the second study compared with nonrubbed eyes. Furthermore, during exposure to cat dander, rubbed eyes consistently exhibited increased chemosis at 5 and 15 minutes (P < 0.05) and increased hyperemia at 5, 15, and 30 minutes (P < 0.05) in the second study compared with nonrubbed eyes. CONCLUSIONS: Firm eye rubbing causes a mild and transient increase in ocular itching, chemosis, and hyperemia. However, after exposure to cat allergens in cat-sensitive individuals, the effects of eye rubbing are longer and more dramatic. Eye rubbing may play a role in ocular signs and symptoms of allergic conjunctivitis in cat-sensitive individuals, especially after exposure to cat dander.

Convergence of auditory nerve fibers onto bushy cells in the ventral cochlear nucleus: implications of a computational model.

1. Convergence of auditory nerve (AN) fibers onto bushy cells of the ventral cochlear nucleus (VCN) was investigated with a model that describes the electrical membrane properties of these cells. The model consists of a single compartment, representing the soma, and includes three voltage-sensitive ion channels (fast sodium, delayed-rectifier-like potassium, and low-threshold potassium). These three channels have characteristics derived from voltage clamp data of VCN bushy cells. The model also contains a leakage channel, membrane capacitance, and synaptic inputs. The model accurately reproduces the membrane rectification seen in current clamp studies of bushy cells, as well as their unique current clamp responses. 2. In this study, the number and synaptic strength of excitatory AN inputs to the model were varied to investigate the relationship between input convergence parameters and response characteristics. From 1 to 20 excitatory synaptic inputs were applied through channels in parallel with the voltage-gated channels. Each synapse was driven by an independent AN spike train; spike arrivals produced brief (approximately 0.5 ms) conductance increases. The number (NS) and conductance (AE) of these inputs were systematically varied. The input spike trains were generated as a renewal point process that accurately models characteristics of AN fibers (refractoriness, adaptation, onset latency, irregularity of discharge, and phase locking). Adaptation characteristics of both high and low spontaneous rate (SR) AN fibers were simulated. 3. As NS and AE vary over the ranges 1-20 and 3-80 nS, respectively, the full range of response types seen in VCN bushy cells are produced by the model, with AN inputs typical of high-SR AN fibers. These include primarylike (PL), primarylike-with-notch (Pri-N), and onset-L (On-L). In addition, Onset responses, whose association with bushy cells in uncertain, and "dip" responses, which are not seen in the VCN, are produced. Dip responses occur with large NS and/or AE, and are due to depolarization block. When the AN inputs have the adaptation characteristics of low-SR AN fibers, PL--but not Pri-N or On-L responses--are produced. This suggests that neurons showing Pri-N and On-L responses must receive high-SR AN inputs. 4. The regularity of discharge of the model is compared with that of VCN bushy cells, using a measure derived from the mean and standard deviation of interspike intervals. Regularity is an important constraint on the model because the regularity of VCN bushy cells is the same as that of their AN inputs.(ABSTRACT TRUNCATED AT 400 WORDS)

Patient-controlled analgesia in a postoperative total joint arthroplasty population.

The present study prospectively evaluated patient-controlled analgesia (PCA) in 94 postoperative primary total joint patients. Total knee arthroplasty patients had significantly higher pain scores than those undergoing total hip arthroplasty. Trochanteric osteotomy patients used less morphine (mean, 37.6 mg) than those undergoing a muscle-splitting (Hardinge) approach. Eighty-eight percent of patients would use PCA again. The authors recommend PCA as a potentially superior form of postoperative pain control in joint arthroplasty patients, but recommend antiemetic usage, generous additional intravenous administration of bolus doses on the floor, trials of higher set doses, and earlier administration of PCA in the recovery room.

Demeclocycline in the prophylaxis of self-induced water intoxication.

Demeclocycline, a competitive inhibitor of antidiuretic hormone at renal tubules, was studied in a patient with the syndrome of psychosis, psychogenic polydipsia, and episodic water intoxication. Under double-blind, placebo-controlled conditions, demeclocycline substantially reduced the severity and frequency of hyponatremic episodes.

Psychosis and water intoxication.

Three cases of psychosis, polydipsia, and water intoxication are presented as examples of a syndrome that is potentially unrecognized in psychiatric settings. Diagnostic and etiologic considerations, with particular attention to the syndrome of inappropriate antidiuretic hormone secretion (SIADH), are discussed through a review of relevant literature. A schema for a routine psychiatric evaluation is described that will minimize overlooking this association of psychosis and disturbed water balance.