Nelson R. Niles

Lack of objective improvement in ventricular systolic function in patients with myocarditis treated with azathioprine and prednisone

Six patients with myocarditis documented by biopsy, after a baseline right heart catheterization and echocardiogram, underwent treatment with azathioprine and prednisone. After 3 months of treatment, biopsy, right heart catheterization and echocardiogram were repeated. In addition to the immunosuppressive therapy, most patients received additional conventional medications for heart failure between evaluation periods (mean number of cardiac drugs increased from 1.7 +/- 1.0 to 2.7 +/- 0.05, p = 0.041). Mean heart rate decreased (105 +/- 14 to 84 +/- 13 beats/min, p = 0.016), as did pulmonary wedge pressure (23 +/- 8 to 12 +/- 4 mm Hg, p = 0.012). There were no significant changes in cardiac index (3.1 +/- 0.8 to 2.9 +/- 1.0 liters/min), end-diastolic dimension (62 +/- 13 to 62 +/- 12 mm) or fractional shortening (11 +/- 6 to 12 +/- 3%) with treatment. Complications from immunosuppressive therapy included severe soft tissue infection, acute psychosis and adrenal insufficiency in one patient each. The benefits from prednisone and azathioprine in this group of patients have not been demonstrated. Although heart rate and pulmonary wedge pressure decreased, these changes could be ascribed to increases in the conventional therapy for heart failure. Finally, there is a high incidence of side effects from prednisone and azathioprine therapy. These findings suggest that this unproven therapy for myocarditis should be limited to experimental protocols.

Female Reproductive System

The female reproductive system consists of two groups of structures, the internal genitalia (Figs. 17.1 through 17.3) located in the pelvic cavity, and the external genitalia (Figs. 17.3 and 17.38) located in the perineum. The former include the ovaries, oviducts (fallopian tubes), uterus, and vagina; the latter include the labia minora, labia majora, and clitoris. Although the breasts are glands ofthe integument and have been described in Chapter 11, they are importantly related to reproductive function and these aspects will be included here.

Male Reproductive System

The male reproductive system (Fig. 18.1) consists of paired primary sex organs, the testes, and a series of secondary sex organs. The secondary organs are the (paired) rete testis, the ductuli efferentes, vas deferens, seminal vesicle and bulbourethral gland, the (single) prostate gland, and penis. The secondary organs are so called because they are dependent on a hormone (testosterone) from the testes for development and maintenance of their structure and function. In addition, there are secondary sex characters, such as hair and fat distribution, form of the laryngeal cartilages and of the pelvis, and sexual behavior patterns, which are also dependent on testosterone.

Organs of Special Sense

The eye is a fluid-filled sphere with a transparent opening through which light enters and is focused on an epithelium whose highly modified cilia are sensitive to the impact of photons. The membrane depolarization initiated by such impact is then passed through a chain of neurons to the eNS, where it is interpreted as light. In the visual cortex the patterns of this nerve activity are translated into images that represent the structure of the external world. Each globe is set in a bony protective socket (the orbit) (Fig. 19.1) within the skull and fitted with six muscles that provide the precise movement needed for the depth perception made possible by binocular vision, as well as for the coordinated tracking movements.

Digestive System, Tubular Portion

The digestive system consists of (1) a convoluted 26-foot epithelium-lined tube (Fig. 12.1), and (2) a number of associated glands derived by evagination and extended growth of the epithelium into or through the other layers of the tube. This chapter deals with the first of these two major subdivisions.

Recapitulation with Variations: “Play It Again, Sam”

One cannot deny the fundamental interdependence ofstructure and function in biology and medicine. This is now a hoary and possibly boring adage. But is it also recognized that structure and function determine the characteristics of disease? Is it understood that diseases are experienced, measured, and classified as they are mainly because of the anatomic parts affected? The history ofquackery depends largely on the lack ofthis perception. How else would anyone accept an elixir not only as a panacea—a cure for countless ills of all sorts—but also as a preventive against any disease? Yet, a little sensible reflection on the complexity and detailed specificity (that is, the fine anatomy and physiology) of the human body can prevent the frauds of quackery. Severed nerve fibers are not induced to regrow and to function normally again by the action ofan odoriferous nostrum. Metastatic cancer will not be overcome by an extract of fruit pits. There is no advantage in overdosage with vitamins. The only likely victory over disease lies in seeing it for what it is and this means looking at it, possibly with old and simple tools or perhaps with new and subtle tricks. But look at it we must; otherwise we are only charlatans whether we admit it or not.

Basic Principles: “What You See Is What You Get”

Histology is largely a visual discipline. Observation is vitally important. For most students, as for Sherlock Holmes, the attainment of this facility of observing and reasoning on the basis ofobservation requires training and practice. In microscopy, as in detective work, one must not simply look; one must look with a system and an objective. The essence of scientific study is to observe and record differences and similarities among a group ofspecimens or circumstances using reliable criteria to determine these characteristics. By distinguishing and identifying form, dimension, and substance one can develop a useful morphologic construct ofcell, tissue, organ, or system. Also, by keeping in mind the physiologic capabilities of individual elements of entire organs and systems one can understand more easily the function of the whole.

Cartilage and Bone

Cartilage has a solid and comparatively firm consistency, although it is not as rigid as bone. In adult humans it functions most importantly as a shock absorber in joints and prevents collapse ofsome tubular structures such as the airway. It also serves in the fetus as the model upon which many ofthe long bones are later built, and it allows rapid growth of these structures as they mature.

Blood and Bone Marrow

Blood is a liquid tissue that is pumped by the heart through the circulatory system. About 45% of the volume of blood is composed of cells; the remaining 55% is liquid plasma in which these cells are suspended. The percentage of blood volume occupied by packed cells, which is determined by centrifugation in a standardized tube, is the hematocrit. This volume varies widely in different diseases (Table 9.1, page 170).