John W. Fertig

The semen of fertile men: statistical analysis of 1300 men.

The prevasectomy semen analyses of 1300 men who had fathered at least two children were studied. The ages of the men ranged from 23 to 64 years, with a mean age of 39.6 years; 84% of the men were Caucasian, 5% were black, and 5% were of other ethnic groups; 32% of the men were Roman Catholic, 26% Jewish, 22% Protestant, and 11% professed no religion; in 9% religion was not recorded. The number of children ranged from 2 (48%) and 3 (30.6%) to 10 (0.1%). The volume of the ejaculate ranged from 0.1 to 11.0 ml, with a mean of 3.2 ml plus or minus 1.4 SD. Sperm density ranged from 1.5 to 375 million/ml, with an arithmetic mean of 79 million/ml plus or minus 57 SD; however, the logarithmic or geometric mean was chosen as being more representative of the asymmetric distribution under study. The geometric mean was 65 million/ml, with standard deviation limits of 30 to 142 million/ml, figures that correspond to the 16th and 84th percentiles. The percentage of motile sperm ranged from 5 to 95%, with a mean of 65% plus or minus 22 SD. The grade of sperm motility, according to MacLeod and Golds classification (Fertil Steril 2:187, 1951) of 0 to 4, ranged from 1 to 4, with a mean grade of 3. There were 25 men (2%) with a sperm count below 10 million/ml and 26 (2%) in whom the percentage of motile sperm was less than 20%. Polyzoospermy (count greater than 250 million/ml) was found in 15 men (1.2%); one or more spontaneous abortions had occurred in six of the spouses of these men (40%), whereas the over-all spontaneous abortion rate was 7% and the spontaneous abortion rate for wives of men with sperm counts below 10 million/ml was 4%. A positive relationship was found between sperm density and percentage of motile sperm; the relationship between motility and the logarithm of sperm density was represented by a straight line (a 10-fold increase in sperm count was accompanied by an increase of 20.4% in sperm motility); the slope of the line was highly significant, although the correlation coefficient was weak (0.27). A similarly positive relationship was found between sperm density and grade of motility; however, the correlation coefficient was also weak (0.22). The relationship between the grade of motility and the proportion of motile sperm also positive, was reasonably large (0.70), although its significance is questionable because of the crudeness of the scale utilized to assess the grade of sperm motility. A comparison of the findings with those of similar studies was made.

Nephrosis of childhood: Statistical evaluation of the effect of adrenocortical-active therapy

Abstract In summary, the evidence now available supports the belief that prolonged and intensive use of adrenocortical-active hormone therapy in childhood nephrosis not only improves the clinical status but also extends life. Only time will tell whether it will prove curative. We have suggested the use of the sedimentation rate as an added simple criterion to help decide when to give or withdraw such treatment.

Studies in the Design and Analysis of Dental Experiments 12. Comparison of Two Measurements of Root Divergence

In odontometric studies, root divergence can be expressed in terms of the ratio of the projected root length to the actual root length (cosine) or as the actual angle itself. Since the distribution of the cosines is skewed and the distribution of the angles is rather symmetrical, the angle measurement is preferable. Various types of significance tests with either measurement will generally not differ greatly, because of the insensitive (robust) nature of these tests.

The clinical dental trial. I. A new caries-inhibitory agent.

V ARIOUS methods of analyzing the clinical effectiveness of caries-inhibitory agents were presented in an earlier published paper.1 Since then, a conference dealing, in part, with the same general theme was held and a report of the discussions published.2 Of particular interest is the part written under the leadership of A. L. Russell, who also summarized the over-all report.3 Other papers dealing with broader aspects of the subject of clinical trials have been published.4 5 6 In addition, a relatively large number of papers have appeared which purport to show the effectiveness of new cariesinhibitory agents, particularly of dentifrices. Believing that these studies are a manifestation of the increasing interest in the clinical dental trial, the authors would like, in this present paper, to discuss, in greater detail, concepts of the design and analysis of studies dealing with caries-inhibitory agents, particularly with dentifrices.

THE SEMEN OF FERTILE MEN: STATISTICAL ANALYSIS OF 1300 MEN

The prevasectomy semen analyses of 1300 men who had fathered at least two children were studied. The ages of the men ranged from 23 to 64 years, with a mean age of 39.6 years; 84% of the men were Caucasian, 5% were black, and 5% were of other ethnic groups; 32% of the men were Roman Catholic, 26% Jewish, 22% Protestant, and 11% professed no religion; in 9% religion was not recorded. The number of children ranged from 2 (48%) and 3 (30.6%) to 10 (0.1%). The volume of the ejaculate ranged from 0.1 to 11.0 ml, with a mean of 3.2 ml plus or minus 1.4 SD. Sperm density ranged from 1.5 to 375 million/ml, with an arithmetic mean of 79 million/ml plus or minus 57 SD; however, the logarithmic or geometric mean was chosen as being more representative of the asymmetric distribution under study. The geometric mean was 65 million/ml, with standard deviation limits of 30 to 142 million/ml, figures that correspond to the 16th and 84th percentiles. The percentage of motile sperm ranged from 5 to 95%, with a mean of 65% plus or minus 22 SD. The grade of sperm motility, according to MacLeod and Golds classification (Fertil Steril 2:187, 1951) of 0 to 4, ranged from 1 to 4, with a mean grade of 3. There were 25 men (2%) with a sperm count below 10 million/ml and 26 (2%) in whom the percentage of motile sperm was less than 20%. Polyzoospermy (count greater than 250 million/ml) was found in 15 men (1.2%); one or more spontaneous abortions had occurred in six of the spouses of these men (40%), whereas the over-all spontaneous abortion rate was 7% and the spontaneous abortion rate for wives of men with sperm counts below 10 million/ml was 4%. A positive relationship was found between sperm density and percentage of motile sperm; the relationship between motility and the logarithm of sperm density was represented by a straight line (a 10-fold increase in sperm count was accompanied by an increase of 20.4% in sperm motility); the slope of the line was highly significant, although the correlation coefficient was weak (0.27). A similarly positive relationship was found between sperm density and grade of motility; however, the correlation coefficient was also weak (0.22). The relationship between the grade of motility and the proportion of motile sperm also positive, was reasonably large (0.70), although its significance is questionable because of the crudeness of the scale utilized to assess the grade of sperm motility. A comparison of the findings with those of similar studies was made.

The clinical dental trial. II. Evaluation of a relaxing drug for operative dentistry.

T HE evaluation of the effects of tranquilizing drugs is subject to tremendous variation both in the effect on the patient and in the observation of the clinician. As a result, some observers feel that the effectiveness of ataractic drugs is either extremely limited or nonexistent, while others believe they are the answer to the problems of the management of the apprehensive patient. It is the purpose of this paper to describe a study of the clinical effectiveness of a new drug in making patients more relaxed for operative dentistry. Particular emphasis will be placed upon the design of the experiment.

A MULTIVARIATE ANALYSIS OF PULPAL RESPONSES OF BILATERAL INTACT HUMAN TEETH

Abstract The use of multivariate analysis on pulp-test readings of three surfaces of bilateral intact maxillary first premolars is demonstrated. As in the case of the analysis of variance performed on these data, it was convenient to use the sums and differences between corresponding surfaces of the two sides. The multivariate tests for surface differences and for the difference in surface profiles between the two sides agreed with the corresponding tests in the analysis of variance. The test for the difference in the surface profiles was adjusted for the overall side difference. The effect of this adjustment was negligible.