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Biomedical subjects

R Katz

Publications and source records attributed to R Katz.

At least 253 records · Page 14Linked to original sources
PubMed1983

Patient readmission to critical care units during the same hospitalization at a community teaching hospital.

The incidence and cause of patient readmission, during the same hospitalization, to a critical care unit was studied in an urban community teaching hospital. During a 12-month period, there were 1069 admissions to the critical care units with 640 patients being at risk for readmission. The readmission rate was 11.7%. Prematurity of transfer out of a critical care unit may have been a contributing factor in 4.2% of the readmissions. Cardiac and respiratory problems were the major contributing causes for readmission. Improved communication between physicians, nurses and therapists could probably decrease premature transfers that contribute to readmission. Enhanced awareness of need for, and ability to provide aggressive pulmonary toilet may diminish the incidence of respiratory relapse. More data is needed regarding acceptable readmission rates; prospective studies are needed to better define the patient population at risk.

Heart Diseases↗
PubMed1983

Multi-center, double-blind, placebo-controlled trial of fluocortin butyl in perennial rhinitis.

Fluocortin butyl (FCB) is a newly synthesized corticosteroid with a high ratio of topical to systemic activity. FCB was studied in a multi-center, double-blind, placebo-controlled trial of therapy of perennial rhinitis. The study was conducted between January and May 1981. Patients evaluated suffered from either chronic allergic or chronic nonallergic rhinitis or both. A total of 306 patients from 16 investigative centers were evaluated by comparing FCB to placebo. Three separate dosage regimens were employed. Patients received a total daily dose of 2, 4, or 8 mg. FCB was found to be an effective therapeutic agent. It reduced symptoms of nasal congestion, rhinorrhea, postnasal drainage, and sneezing. It also markedly reduced the use of concomitant medications (chlorpheniramine maleate and/or pseudoephedrine). Relief of symptoms was noted as early as the first week of therapy, and the degree of improvement increased progressively during the study. There was little difference between the relief produced by the 4 mg and 8 mg regimens. Both of these were superior to the 2 mg regimen. The drug was well tolerated; no significant side effects were noted.

Adult↗
PubMed1983

Anaesthetic uptake by the goldfish: effect of respiratory rate.

In order to assess the uptake of halothane by the goldfish, the respiratory rate of six fish was studied when water temperature was varied with and without changes in oxygen or carbon dioxide tension. The effective dose 50 of halothane (ED-50-H) and the time taken to reach it (T-ED-50-H) at an FIO2 of 0.35 in nitrogen, were studied when temperature and CO2 tension were varied. Nomograms were drawn to predict respiratory rate as a function of water CO2 tension, when CO2 was bubbled in air or in oxygen, and with changes in water temperature. At low temperatures (5 degrees C to 7.5 degrees C), respiratory rate remained below 10 per min, irrespective of CO2 partial pressure. At 28 degrees C, a CO2 partial pressure of 8 +/- 0.2 kPa produced a respiratory rate of 125 +/- 3/min in air, and in oxygen unexpectedly 140 +/- 3/min. Halothane ED-50 varied with temperature (0.8% at 10 degrees C and 1.6% at 23 degrees C). Time to reach ED-50-H decreased with increases in respiratory rate, but increased as water temperature was elevated.

Animals↗
PubMed1983

Osteomyelitis of both clavicles as a complication of subclavian venipuncture.

Complications of subclavian vein catheterization are common and include pneumothorax, hemothorax, and sepsis. Osteomyelitis is a rare complication. The present report describes a patient with osteomyelitis of both clavicles due to subclavian vein venipuncture, in whom fever and chills were absent and the sole clinical finding was local pain and tenderness in the involved area.

Aged↗
PubMed1983

Double-blind comparison of acute effects of inhaled albuterol, isoproterenol and placebo on cardiopulmonary function and gas exchange in asthmatic children.

Although albuterol aerosol is an effective bronchodilator in adult asthmatics its efficacy and safety are not fully established in asthmatic children. Albuterol (100 and 200 micrograms), isoproterenol (70 and 140 micrograms) and placebo were administered from metered dose aerosol cannisters to 11 asthmatic children (9 to 16 years of age). Our findings indicate that in asthmatic children albuterol aerosol causes bronchodilation for up to six hours and greater bronchodilation than comparable doses of inhaled isoproterenol and does not produce overt effects on the cardiovascular system, significant changes in arterial partial pressure of oxygen or excessive tremor.

Adolescent↗
PubMed1982

Comparison of soleus H reflex facilitation at the onset of soleus contractions produced voluntarily and during the stance phase of human gait.

Variations in the soleus monosynaptic reflex have been studied in normal human subjects during soleus contractions while walking, and compared with those observed during voluntary soleus activation. The monosynaptic reflex was always more facilitated during voluntary contractions than during walking. The EMG activity was identical in both situations. Under the assumption that this reflects an identical excitability of the motoneuronal pool, this different soleus H-reflex facilitation can be attributed to a difference in the excitatory efficiency of the group I volley evoked by the H-reflex stimulation. It is suggested that the level of presynaptic inhibition exerted on Ia fibers could be lower during walking than during voluntary contraction.

Ankle↗
PubMed1982

Effects of chronic partial deafferentiation on the electrical properties of lumbar alpha-motoneurones in the cat.

Membrane properties of cat spinal alpha-motoneurones were compared in cats following acute and chronic low (L5) spinal section and dorsal rhizotomy (L7--S1) and in cats with intact spinal cord in order to investigate effects of chronic partial deafferentation. The most significant change observed was a decrease in electrotonic length of the chronically deafferented neurones. Calculations showed that this decrease was related to a 15--20% reduction in length of an equivalent cylinder used to represent a motoneurone. Using a compartmental model, calculations showed that the peak voltage produced by a given synaptic input would be increased by 6--36% by chronic section. Such an increase is not sufficient to explain reported increases in EPSP peak amplitudes. Neither peak amplitude (and underlying conductance change) nor duration of the afterhyperpolarizaton were affected by the acute or chronic sections. No obvious changes in the delayed depolarization were observed. The properties of the repetitive discharge induced by intracellular current injection was not altered by chronic section.

Action Potentials↗
PubMed1982

The transverse cervical trapezius myocutaneous island flap.

The transverse cervical trapezius myocutaneous island flap has demonstrated superior versatility and reliability when used in a series of eight patients. The technique differs from the previously described lateral trapezius myocutaneous flap in that the skin is centered more posterosuperior in the neck and is completely undersurfaced by a larger paddle of trapezius muscle. Experience has shown that surgical defects of the oral cavity, oropharynx, hypopharynx, and skin of the cheek may be repaired with this flap with an acceptable incidence of complications. The advantages and disadvantages of this flap compared with other popular myocutaneous flaps are discussed.

Cheek↗
PubMed1982

Meperidine-promethazine combination and learning function of mice and of their progeny.

Twenty mice aged three to four months and trained to find food in a six compartment maze after a 24 hour fast, were divided into two equal groups. For just over one month the group which had received intraperitoneal meperidine 3 microgram.g-1 and promethazine 1.66 microgram.g-1 performed significantly slower than the group which had received intraperitoneal physiological saline. Because of this marked effect, it was decided to investigate the action of the drug combination on brain development and to assess whether it produced permanent retardation in learning function. The dams of a second group of 12 mice were, therefore, given either the same dose of drug combination or saline. At the age of seven weeks, the six pups born to dams which had received intramuscular saline and the six born to dams which were given intramuscular promethazine with meperidine performed equally well in a series of tests conducted in a T maze and in the six compartment maze after a 24 hour fast. In the T maze they had to distinguish between the presence of food provided in diminishing amounts or no food. In the six compartment maze they were tested with multiple maze pattern sequences. Meperidine and promethazine given during early labor does not permanently affect the learning function of the progeny of mice.

Aging↗
PubMed1982

Recurrent inhibition of alpha-motoneurons in patients with upper motor neuron lesions.

The recurrent inhibition of alpha-motoneurons by Renshaw cells, brought about by a conditioning reflex discharge, was estimated by measuring the amplitude of a test reflex which involved only those soleus motoneurons which had already fired in response to the conditioning volley. The results obtained in 95 patients with upper motor neuron disease and in 31 normal subjects were compared. At rest, there was no evidence for a decrease in the excitability of Renshaw cells: on the contrary, recurrent inhibition, if it changed at all, was increased in 55 out of 95 patients. In most patients the changes in Renshaw cells excitability which occur during postural or voluntary contractions in normal subjects were not found. We conclude that changes in recurrent inhibition are not responsible for the hyperexcitability of the stretch reflex which characterizes human spasticity. On the other hand, the paralysis of the supraspinal control of Renshaw cells, which normally accompanies voluntary movements, could account in part for two difficulties exhibited by spastic patients: in grading the strength of a muscular contraction, and in regulating reciprocal Ia inhibition according to the requirements of a voluntary movement.

Adolescent↗
PubMed1981

Cutaneous depression of Ib reflex pathways to motoneurones in man.

Variations in the H-reflex of soleus (Sol), quadriceps (Q) and short head of biceps femoris (Bi) muscles in normal man were used to investigate the effect of volleys in low threshold cutaneous afferents from the ipsilateral limb on transmission of Ib effects from ankle and Q muscles to these different motoneurone (MN) pools. Stimulation of cutaneous afferents from the foot sole and the toes (but not from the thigh, knee or calf), which did not modify the size of the test reflexes when applied alone, strongly depressed Ib reflex pathways to MNs supplying muscles operating at the knee. The very brief central latency of this depression suggests that tactile cutaneous afferents from the foot have oligosynaptic spinal connexions with the interneurones intercalated in the Ib pathways to MNs. The same cutaneous stimuli did not all modify Ib inhibition of Sol MNs from triceps surae. These findings are discussed with regard to the role of the different muscles in human locomotion. It is suggested that during the stance phase of heel bipedal locomotion, the cutaneous depression of Ib reflex pathways to MNs supplying muscles operating at the knee might operate in association with the strong Ia connexions from ankle to knee muscles described in the previous paper.

Adult↗