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Biomedical subjects

H Kaufman

Publications and source records attributed to H Kaufman.

126 records · Page 7Linked to original sources
PubMed1968

Photoregulation of an enzymic process by means of a light-sensitive ligand.

A specific inactivator of chymotrypsin, p-azophenyldiphenylcarbamyl chloride, exists as two geometric isomers, cis and trans, which are interconvertible by means of light. The cis-isomer is five times more reactive than the more stable trans-isomer, and is obtained by exposure of the latter to light of 320 nanometer wavelength. The trans-isomer can be regained by exposure of the cis-isomer to light of 420 nanometer wavelength. This interconversion can be made to occur in aqueous solution in the presence of the enzyme under conditions in which the trans-isomer reacts relatively slowly with chymotrypsin. Thus, it is possible to regulate the rate of inactivation of chymotrypsin by using light of the appropriate wavelength. This system is presented as a model for some of the light-sensitive metabolic systems present in living organisms.

Adenosine Triphosphate↗
PubMedDate not supplied

Saving the frontal branch during a low fronto-orbital approach.

This report describes the anatomy of the frontal branch of the seventh nerve and a technique for assuring its preservation when doing a low frontal approach. By dissecting under both layers of the temporal fascia, rapid and safe access to the inferior fronto-orbital region may be achieved. This technique is recommended for exposure of a bony lesion in the fronto-orbital region and when performing an osteoplastic pterional craniotomy.

Child↗
PubMedDate not supplied

[Standardization of the peak expiratory flow rate].

Five successive measurements of the peak expiratory flow rate have been made on a large number of children and adolescents in various age groups and both sexes. The predominant part of the increase in individual performance is already achieved during the first three trials. Besides, the maximum value of the five measurements apparently does not differ essentially from the mean value of the two or three highest measurements.

Adolescent↗
PubMedDate not supplied

Double-masked, paired-comparison clinical study of ketorolac tromethamine 0.5% ophthalmic solution compared with placebo eyedrops in the treatment of seasonal allergic conjunctivitis.

In a multicenter, double-masked, clinical study, we compared the ocular safety and efficacy of ketorolac 0.5% ophthalmic solution with placebo in alleviating the signs and symptoms of allergic conjunctivitis. The study was conducted in 93 patients who received one drop of the appropriate treatments in each eye, four times a day, for seven days. Of these subjects, 74 were evaluated for efficacy. The principal clinical sign of allergic conjunctivitis, conjunctival inflammation, and six allergic symptoms (itching, swollen eyes, burning or stinging, discharge or tearing, foreign body sensation, and photophobia) were evaluated by the investigators at midweek (day 3 or 4) and at the end of the study (day 7 or 8). Ketorolac was superior to placebo in reducing conjunctival inflammation (p = 0.003) and itching (p = 0.020), the principal clinical symptom, at the final examination. In addition, ketorolac was favored over placebo in reducing the other five symptoms evaluated. On the day of final examination, overall therapeutic response evaluated by the investigators rated ketorolac as superior to placebo (p = 0.007). A significant placebo effect was noted in this study, as has been previously reported in clinical studies of allergic conjunctivitis patients. Results of this study demonstrate that 0.5% ketorolac ophthalmic solution used topically four times daily, for seven days, was effective in alleviating the principal sign and the symptoms associated with allergic conjunctivitis.

Adult↗
PubMedDate not supplied

Issues in the design of a multirate model-based controller for a nonlinear drug infusion system.

Multivariable controller design for the regulation of mean arterial pressure (MAP) and cardiac output (CO) in congestive heart failure patients is restricted by the limited frequency of CO sampling. Performance criteria for the controller specify maximum allowable transient settling times for both variables, and the design should account for the inherent multirate nature of the process in order to satisfy these criteria. We present a multirate model predictive control (MPC) design for MAP and CO regulation by combined infusion of sodium nitroprusside and dopamine, based on a comprehensive nonlinear model of the system. The multirate MPC algorithm is based on nonlinear quadratic dynamic matrix control. To reduce computation time, we introduce a selective linearization technique that linearizes the model on the basis of trends in the plant-model mismatch. The problem is complicated by restrictions on initial dopamine infusion, prescribed to avoid extremely slow responses. We present a novel rule-based override (RBO) to the MPC controller that uses a set of heuristics to initialize dopamine. The performance of the MPC/RBO controller is illustrated using simulation results.

Algorithms↗
PubMedDate not supplied

Control of a nonsquare drug infusion system: A simulation study.

A model predictive control strategy was developed and tested on a nonlinear canine circulatory model for the regulation of hemodynamic variables under critical care conditions. Different patient conditions such as congestive heart failure, post-operative hypertension, and sepsis shock were studied in closed-loop simulations. The model predictive controller, which uses a different linear model depending on the patient condition, allowed constraints to be explicitly enforced. The controller was initially tuned on the basis of a linear plant model, then tested on the nonlinear physiological model; the simulations demonstrated the ability to handle constraints, such as drug dosage specifications, commonly desired by critical care physicians.

Animals↗
PubMedDate not supplied

A comprehensive school-based clinic: university and community partnership.

PURPOSE: To describe the evolution and current status of a university and community partnership engaged in operating an urban elementary school-based clinic (SBC) POPULATION: The children at the school who are eligible to receive care at the SBC include 500 elementary students and 200 adolescents who attend a magnet junior high school housed in the same building. The vast majority of the children attending the school are from families whose incomes are below the national poverty level. Eighty-five percent of the children are black. Fifteen percent are Hispanic, non-white. CONCLUSIONS: A variety of services and programs are offered to the children and their families for the promotion of health and the prevention of mental disorders. Service, education, and research occur simultaneously to achieve the multiple goals of the partners and participants. PRACTICE IMPLICATIONS: Advanced practice nurses can provide quality health and mental health care services for school-age children and their families through SBCs. Institutional partnerships, capitalizing on each other's strengths, can expand the availability of SBC offerings.

Adolescent↗
PubMedDate not supplied

Total and free testosterone and estradiol in human semen.

Total and free testosterone (T) and estradiol (E2) were determined by a radioimmunoassay technique in 30 normozoospermic and oligozoospermic human semen samples. The mean amounts of total T ranged from 25.1 +/- 7.4 to 32.5 +/- 12.2 ng/100 mL, and those of the free hormone from 7.0 +/- 2.8 to 7.9 +/- 2.3 ng/100 mL. The values for E2 were 10.5 +/- 4.4 to 11.2 +/- 4.5 pg/mL and 2.3 +/- 1.1 to 3.2 +/- 2.6 pg/mL, respectively. There was no correlation between sperm density of semen and the levels of T and E2. It is suggested that the nonspecific binding of T and E2 in semen provides a physiological reservoir for active, free T and E2 and that an appropriate ratio of free T to free E2 in semen may be crucial in the processes that lead to fertilization.

Adult↗
PubMedDate not supplied

Maternal and cord plasma cortisol and aldosterone levels at delivery, in various ethnic groups in Israel. Preliminary report.

This study was carried out to evaluate the maternal venous and umbilical cord blood levels of cortisol and aldosterone at spontaneous delivery in three ethnic groups in Israel (Ashkenazic, Sepharadic and Oriental) (n = 47). The mean maternal plasma cortisol level of the Sephardic group was significantly lower than were those of the other groups (P less than 0.01). Cord plasma cortisol level was similar in the three groups. No statistical differences were noted between the maternal and cord plasma cortisol levels in the three groups. The mean maternal and cord plasma aldosterone level was lowest in the Sephardic group. There was a good correlation of maternal and cord aldosterone levels in all of the groups. A positive statistical correlation detected in our study between levels of maternal plasma cortisol and cord plasma aldosterone is of interest, but needs more investigation before an appropriate explanation can be formulated. The ethnic differences in hormonal changes at birth observed in this study are preliminary results, and further investigations are being conducted to clarify these findings.

Adult↗
PubMedDate not supplied

Considerations and preparations for making managed care part of your practice.

The decision to integrate managed care into the traditional FFS practice is one that requires careful consideration. Should you decide that it offers your practice an attractive opportunity to fill empty chairtime while positioning the practice for positive growth, now may be an opportune time for involvement. Furthermore, embracing a new mind-set could prove to be an invaluable business move-change is essential, no matter which path is taken. Most consultants believe that dentists who expand their horizons now will maintain a competitive edge over those who stick with more traditional methods of operation. As with any industry, it is important to aim for where things are going, not for where they have been; the positive focus should be on the dental practice of the future. According to Reengineering the Corporation (HarperBusiness, 1993) by Hammer and Champy, businesses today must not forget the three Cs: customers, competition, and change. The book points out that the customers are in charge, the competition has intensified, and change is a constant. The decisions made now regarding the direction of dental practices will determine how dentists deal with the forces in this uncharted future.

Dentist-Patient Relations↗