The use of a microcomputer for collecting screening ...

Drug Development Research 3:475-482 (1983)

The Use of a Microcomputer for Collecting Screening Data and for Conducting Range Finding Experiments on Muscle Relaxant Drugs Paul D. Thut, Gregg Polansky, and Frieda G. Rudo Department of Pharmacology, School of Dentistry, University of Maryland, Baltimore ABSTRACT Thut, P.D., G. Polansky, and F.G. Rudo: The use of a microcomputer for collecting screening data and for conducting range finding experiments on muscle relaxant drugs. Drug Dev. Res. 3:475-482, 1983.

This report describes a method that has been developed to use an Apple II Plus microcomputer in data collection, data analysis, and transfer of raw and summary data to a data base that is maintained on a larger computer. The compounds being screened are potential skeletal muscle relaxants acting at the neuromuscular junction. The microcomputer produces a CRT (cathode ray tube) display resembling the data sheets previously used in a drug screening project. It prompts the user to enter the following data through the keyboard: compound number, date, drug solution, animal weight, desired compound dose. From the entered data, the microcomputer calculates and displays the appropriate injection volume so that a technician will be shown the exact dose that is to be injected into the test animal. Following injection, the mouse is immediately placed on an inclined screen as described by Pradham and De [1953].Times to onset and offset of muscle paralysis are entered and displayed on the CRT. For lower doses, the effects of the drug on respiration are recorded. After these primary data are recorded, all other relevant data are elicited by a menu of appropriate pharmacological questions. Data from each animal are stored in a random access file on a 5.25-in. floppy disk. From these files tabular and narrative reports of the drug’s effects can be automatically generated. The data are also sent by telephone modem to a data base that is maintained on a larger computer for access by chemists in structure-activity studies. This method has greatly increased the speed and efficiency of data collection and report generation. Furthermore, it has allowed the raw data to be easily Received final version May 27, 1983; accepted May 27, 1983. Address reprint I ,quests to Dr. Paul D. Thut, Department of Pharmacology, Baltimore College of Dental Surgery, Dental School, University of Maryland, 666 West Baltimore Street, Baltimore, MD 21201.

0 1983 Alan R. Liss, Inc.

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searched and reviewed in subsequent structure-activity studies. Because this data collection system is small and self-contained, it may be moved easily to different testing sites. Key words: drug screen, microcomputers, muscle relaxants INTRODUCTION

Our laboratory is in an academic setting, and it provides a screening service to a group of industrial chemists located in another state. Each month, between 10 and 20 newly synthesized compounds are tested for skeletal muscle relaxant activity. In the past, after animals were weighed, the doses and injection volumes were calculated using a hand-held calculator. A variety of doses were administered to establish a dose-response curve of muscle relaxation, lethality, and side effects for each compound. Data sheets were used to record observed affects of the compounds. Data were evaluated and summarized, and a report of the activity of each compound was written by the laboratory director (a Ph.D. level pharmacologist). Reports were typed by a secretary and were mailed to the contracting company. The data were then manually entered into a data base maintained on a larger computer. The following is a description of the use of a microcomputer system to collect data automatically, write reports, and electronically transfer the data to the central data base. METHODS

The screening system (Fig. 1) is designed around an Apple I1 Plus microcomputer (Apple Computer, Inc., Cupertino, California). The standard 40-column video display of the Apple is expanded to 80 columns by inserting a “Videoterm” 80-column display board (Videx, Inc., Corvallis, Oregon) into expansion slot No. 2 of the Apple. The Videoterm displays both upper and lower case letters and all other American Standard Code for Information Interchange (ASCII)-defined printing characters. In addition, a line drawing graphic character display integrated circuit chip (Videx, Inc., Corvallis, Oregon) has been installed on the Videoterm circuit board to provide the lines required when displaying the test data form. One 5.25-in. floppy disk drive (Apple Computer, Inc., Cupertino, California), providing approximately 83K of permanent storage for programs and data, is attached to the computer. A 9-in. green phosphor CRT monitor (Sanyo, Compton, California) is used to display input and results of calculations. Raw data are printed on a dot matrix printer (Epson, Torrance, California). This system is portable and is provided with a carrying case. It is also compact enough to fit on a small laboratory cart or scientific bench top. In our laboratory, the data reduction, report writing, and data transfer system (Fig. 1) employs a second Apple I1 Plus microcomputer. However, one microcomputer could be configured to perform both functions. The second computer has a 16 K RAM expansion card in Apple expansion slot No. 0, thus providing a total of 64K of memory. It also contains a Videoterm board in slot No. 2. A NEC 5510 Spinwriter character printer, used for table preparation and report generation, is connected by a RS232 serial interface in slot No. 1. Two disk drives, connected to Apple expansion slot No. 6, are used to store data and programs. A Mountain Hardware clock, in slot No. 7, provides the ability to date records and Hayes Microdem 11, in slot No. 5, provides the transfer of data through telephone lines, at 300 baud, to a Data General MV 8000 computer in another state. The program used to drive the screen displays, collect the variables, and store them to disk, is written in Applesoft BASIC computer language. The program uses language and graphic extensions made possible by the addition of the Videx options mentioned above. BASIC was selected because of the ease of original programing and subsequent program maintenance and enhancement and because speed of calculation is not crucial in this application. The program used to transfer data from disk files to printed forms is also written in BASIC. Word processing software, Super Text 11, 40180-column version by Muse Software, is used to generate written summaries. Data Capture 4.0 by Southeastern Software runs the communications hardware.

Use of a Microcomputer in Drug Screening

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Fig. 1. (Top panel) Configuration of microcomputer used in collecting muscle relaxant screening data. Input devices and various output devices are illustrated. (Lower panel) Configuration of microcomputer used in generation of table and narrative reports on activity of potential skeletal muscle relaxant compounds. Input devices and various output devices are illustrated.

The data collection and storage is controlled by a program, SCREENING (Fig. 2 ) , which has two menu driven subroutines. The first menu is a CRT display that has been created to look as similar to previously used data collection forms as possible. The cursor is moved around in the CRT data form display, under program control, to prompt the technician’s responses. The program currently prompts the user to enter as many as 25 pharmacological variables. In its current configuration, the program allows collection of these data for as many as 100 animals for each test compound. However, fewer than 25 mice are usually used in these preliminary range finding experiments. Mice are injected one at a time, and the pharmacologic effects of each test dose are completely evaluated before another mouse is treated (Pradham and De, 1953). This program-directed experimental design encourages the technician to make a thorough evaluation of the drug’s effects in each animal, at all dose levels. When the technician is satisfied that the dose-response has been completed between doses that produce no observed effects and those that produce immediate death, the data are stored on a floppy disk with the compound’s code name serving as the file name. The disk storage subroutine of the computer program uses Apple’s random access files. The data of each animal are stored as a record in the file. The first element in the file record is the animal number. Other elements of the record are either string, real, or integer variables that are codes for data or are actual observed data values. The final 100 elements of the record are reserved for written notes of any unusual responses that the technician may want to add to the report. All data are printed on the Epson dot matrix printer immediately following the disk storage operation. The printed data record is dated automatically and is signed by the technician. This hard copy of the raw

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Fig. 2. Flow chart of program, SCREENING, used to input screening data on potential skeletal muscle compounds.

data is retained as a backup in case of computer failure and is checked against the data in the written drug evaluation report. At frequent intervals, the laboratory director takes the raw data disk files to the second Apple computer and uses a menu driven program, REPORT WRITER (Fig. 3), to prepare a raw data form (Fig. 4) and a tabular summary of the results (Fig. 5). This program collects all mouse records from the “Compound file,” sorts the data by dose, and calculates the means of

Use of a Microcomputer in Drug Screening

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Fig. 3. Flow chart of program, REPORT WRITER, used in generation of tabular and narrative reports of activity of potential skeletal muscle compounds.

primary data (onset, duration, etc.) and summaries of observational data [cyanosis, depressed respiration, etc. (Fig. 5 ) ] . The summary data are also stored on an Apple disk until they can be transferred to a data base that is maintained on a larger computer. Narrative summaries are then added to the tabular summaries by using the word processor software. Several general categories of summary are stored in the word processor files, i.e., further study, hold, terminate, or screen for anticonvulsant activity. These general summaries are easily modified

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Fig. 4. Raw data report form that is completed by computer program, REPORT WRITER. The following abbreviations are used: IMM. = immediate onset; NA = not applicable; / = depression; + to + + + = intensity of effect; - = no effect. to reflect unique features of the agent currently being studied. The summaries are then printed on the report form provided by the chemist. The report is then dated and signed by the laboratory director and the immediate supervisor and is mailed to the contractor. As appropriate, the compound name, its “lowest effective dose” (LED) and the date last tested arc added to a further study (FS) list, which is kept by sequential synthetic numbers. The compound name is also added to a priority of testing list, which is kept by LEDs. RESULTS AND CONCLUSIONS

Use of these microcomputer systems in our screening program has provided several advantages over the previous, manual methods. First, the program ensures that all data are

Use of a Microcomputer in Drug Screening

CO.'LPOUND NO.:Tuhocurarlne

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481

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SUMIYARY T U B O C U A A R I N E STANDARD p r o d u c e d M . R . a f t e r a d o s e o f . 1 mg/kg. U r i n a t i o n and s a l i v a t i o n occured o n l y a f t e r d e a t h . Tremors occured a f t e r a d o s e o f . 1 mg/kg. The compound had a n i m m e d l a t e o n s e t o f action. T h e r e was a s h o r t d u r a t i o n of a c t i o n . The compound i s h i g h l y potent.

Fig. 5 . Summary report form that is completed by computer program, REPORT WRITER. The following abbreviations are used: I.D. = immediate death; M.R. = muscle relaxation; urin. = urination; relax. = general muscle relaxation; saliv. = salivation.

collected consistently and completely. Computer calculation of injection volumes reduces those errors associated with incorrect volume calculation to a minimum. Using the CRT to display the test sequences, the technician is directed to record all the required observational data in the same sequence for each animal. Furthermore, only one animal at a time can be treated and observed, thus ensuring that each animal receives a complete evaluation. Several different technicians conduct this screen and use of the computer has improved the intertechnician consistency of results.

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Data are stored in both electronic and printed forms and need not be reentered for further calculations, thus preventing subsequent typographical errors. If an entire doseresponse curve is not completed in a single screening session, it may be completed at a later time after which results from the noncontinuous test may be examined and will appear as if the test were continuous. The computer and its programs therefore ensure complete consistency in data collection. Data are transferred to a form containing the compound’s structure, its physical characteristics, and the date of preparation, which was sent to the laboratory by the chemist at the same time that the test compounds were shipped to the laboratory. All reports are written in a consistent format because the computer collects and summarizes all collected data in the same manner for each compound. While actual data gathering time may not be reduced, the process of report generation is greatly accelerated, ensuring timely generation of reports and consistency of data and formats. Based on the compiled data observed, the computer prograin suggests a narrative summary and the steps for further study of the compound. This ensures that each compound will be treated in an identical fashion in the screening program. The laboratory chief may alter the narrative to reflect any unique characteristics of the compound. Formerly, a secretary spent 2 days per week typing data tables and reports. These microcomputer programs eliminate this secretarial expense, with its apparently unavoidable typographical errors. All raw data and summary data are transferred, without need for alteration, to a large mainframe data base system. This allows chemists to utilize the data base as they conduct structure-activity studies in planning the designs of future compounds for both the muscle relaxant synthetic program and other synthetic programs. As screening activity and the variety of compounds synthesized for potential in other pharmacological categories have increased, this computerization of screening has proved more and more valuable. The larger the screening effort and the more individuals involved, the more valuable such a portable and general computerized screening system becomes. The major difficulties in producing an operational system involved designing the input screens, the data base, and the communications program. Many large pharmaceutical firms, with in-house screening programs, probably already have data base systems and would not need long distance communications of data, but they could derive great benefit from local automation of screening procedures. In situtations where remote screening sites are utilized, the consistency provided by this computerized technique would prove most valuable. These programs are a relatively new addition to our research effort and they have already demonstrated their utility by providing increased efficiency and consistency. The time saved by using these programs is being used to conduct further studies on the most promising of these newly synthesized compounds. ACKNOWLEDGMENTS

The authors express their appreciation to Mr. Conrad T. Cordes for his valuable technical assistance throughout development of these procedures. REFERENCE Pradham, S . N . , and De, N.N.: Hayatin methiodide: New curariform drug. Br. J. Pharmacol. 8:399-405, !%3.