An interpretation of the structural changes responsible for the chronicity of rhinoscleroma.

OBJECTIVE: To identify the structural changes of the proliferative phase of rhinoscleroma which could be responsible for the chronicity of the disease. STUDY DESIGN: Observational research. METHODS: Samples of friable tissue taken from the nasal mucosa of nine untreated patients were processed for light and ultrastructural microscopy. RESULTS: The majority of changes contributing to the chronicity of the disease occurred in the subepithelium and followed three closely related but distinct events. In the first (infiltrative), subepithelial invasion by the Klebsiella was followed by its active multiplication and proliferation of capillaries. In the second (neutrophilic), large numbers of neutrophils were delivered into this space. Neutrophils actively phagocytized the Klebsiella but appeared to die at an accelerated rate without completing digestion of the microorganisms. In the third event (histiocytic), histiocytes entered the subepithelium and engaged in unrestrained phagocytosis of decaying neutrophils, Klebsiella, and debris. During this process, the histiocytes' phagosomes underwent massive dilation, thus becoming Mikulicz cells. Mikulicz cells were unable to consistently destroy the Klebsiella and eventually ruptured, releasing them into the interstitium. Evidence was found that an autophagic process might contribute to phagosome distention and to the rupture of the vacuolar membranes and cell wall. CONCLUSIONS: Several critical changes responsible for the chronicity of rhinoscleroma occur during the proliferative phase of the disease. The majority of these take place in the subepithelium and include: 1) factors leading to the transformation of histiocytes into Mikulicz cells, 2) the inability of these cells to consistently destroy the Klebsiella, 3) their rupture releasing viable Klebsiella, and 4) the intrinsic resistance of the pathogen.

Serum lipid and lipoprotein patterns in patients with liver cirrhosis and chronic active hepatitis.

BACKGROUND: An impaired lipid metabolism is often found in patients with chronic liver diseases. Unfortunately, few studies are available concerning serum lipid and lipoprotein levels in patients with liver cirrhosis and chronic active hepatitis (CAH). OBJECTIVES: To evaluate low-density lipoprotein (LDL), high-density lipoprotein (HDL), very low-density lipoprotein (VLDL), and total cholesterol serum levels in patients with cirrhosis and CAH and control patients and to relate the findings to the severity of the cirrhosis (Child classification). METHODS: We measured the serum lipid pattern in 34 consecutive patients with liver cirrhosis (15 men and 19 women; mean [+/-SD] age, 55 +/- 14 years; Child classes: 14 in A, 9 in B, 11 in C; patients with biliary cirrhosis were excluded), 34 patients with CAH, and 34 control patients. The 3 groups were matched for sex and age. Total serum, HDL cholesterol, and triglyceride levels were measured by enzymatic methods; serum LDL and VLDL levels were calculated. RESULTS: In patients with cirrhosis, there was a significant decrease in LDL, HDL, and total cholesterol serum levels compared with both the patients with CAH and the control patients, while the VLDL cholesterol level in patients with cirrhosis was significantly lower compared with the control patients alone. A significant decrease in total cholesterol levels was also observed in the CAH group when compared with the control patients. In patients with cirrhosis, levels of LDL, HDL, and total serum cholesterol were progressively lower when comparing patients in Child class A with patients in class C. CONCLUSIONS: In this study, the striking decrease in the level of serum LDL cholesterol in patients with liver disease was related to the increasing severity of the disease. Accordingly, the assessment of the serum LDL cholesterol level is important for an effective treatment and prognostic evaluation of patients with chronic liver disease.

Sperm structure and its relevance to infertility. An electron microscopic study.

In this article, I review the submicroscopic organization of the human spermatozoon, the functional role of its individual organelles in motility, penetrating ability, and fusogenic and fertilizing competence, and its pathology as a cause of male infertility.

Binding of sperm to somatic cells via HLA-DR. Modulation by sulfated carbohydrates.

We have shown previously that human sperm bind and enter leukocytes expressing surface HLA class II molecules. In the present study, mutant B lymphoblastoid cells and HLA-DR-transfected murine 3T3 fibroblasts are used to confirm that HLA class II molecules are somatic cell receptors for sperm. Further, for isolated HLA-DR expressed on murine cells, we show that sperm receptor activity requires the presence of sulfated carbohydrates. As carriers of multiple HLA-DR binding ligands, sperm may 1) mimic the target cell-activating effects of anti-DR antibody and 2) bind HIV through CD4-like or alternate receptors. By these or other mechanisms, sperm/somatic cell interactions in the female reproductive tract may affect fertility and potentiate the sexual transmission of AIDS.

Physiology and pathophysiology of the human spermatozoon: the role of electron microscopy.

In this article, the major contributions of electron microscopy to the present understanding of the physiology and pathophysiology of the human spermatozoon are reviewed. The ultrastructural organization of sperm organelles playing a significant role for cell function and, therefore, for the reproductive process is described. Also, the major abnormalities and defects of the various organellar systems and how they impair the reproductive function and/or the viability of the cell are reviewed.

Clinical relevance of evaluation of sperm and ova.

The various methods currently available to assess the structural and functional fitness of the spermatozoa for the reproductive process have been reviewed. The semen analysis remains the single most important predictor of male fertility potential, even though sperm motility and morphology are inadequately and subjectively evaluated. Of the various tests used to assess sperm penetrating ability, the zona-free hamster oocyte penetration assay probably is the most useful and most widely used, especially to screen the penetrating competence of spermatozoa to be used for extracorporeal insemination procedures. However, several important limitations prevent it from being a definitive method for the assessment of fertility. The electron microscopic examination of the sperm as complementary to semen analysis and the zona-free hamster oocyte penetration assay is an important procedure, in that it permits a detailed assessment of the structural integrity, and hence the functional adequacy, of the various subcellular components that are responsible for cell motility, penetrating competence, and fertilizing ability. Unfortunately, the oocyte escapes analytical methods.

Germinal cell ectopism in the strepsirhine prosimian Galago crassicaudatus crassicaudatus.

The presence of germinal cells outside of the embryonal and fetal gonads of the strepsirhine prosimian Galago crassicaudatus crassicaudatus is described. Forty-three embryos and fetuses from day 26 or 27 of gestational age to near term were studied: more than 90% possessed germinal cells in ectopic sites situated either far from (extragonadal ectopism) or close to the gonads (perigonadal ectopism). The first sites were the walls of the aorta and mesenteric artery, the stroma between the aorta and the cardinal vein, and the retroperitoneal neuroganglia. The second were the mesenchyme dorsal to the gonads and around the vestigia of the mesonephric glomeruli and tubules, and the rete ovarii and testis. The ectopic cells were generally present in conscpicuous numbers, in some animals being more numerous than in the gonads. Those situated far from the gonads underwent degeneration and decreased significantly in numbers during post-embryonal stages of development, while the others remained numerous and functionally active up to near term. While the differentiation of the extragonadal germinal cells after day 60 of gestational age could not be studied due to technical difficulties, the XX and XY cells in perigonadal sites appeared to follow patterns of differentiation identical to those of their entopic counterparts.

The development of the sexually indifferent gonad in the prosimian, Galago crassicaudatus crassicaudatus.

The morphogenesis of the sexually indifferent gonad of the primate Galago crassicaudatus crassicaudatus was studied by high-resolution light microscopy and electron microscopy in 15 embryos aged 26 to 33 days. Onset of gonadal development follows the morphogenesis of the mesonephros by a conspicuous interval and is identified as the time when the first primordial germinal cells arrive in the region ventral to the central third of the mesonephros; this is followed by intense proliferation of the coelomic mesothelial cells lining the area. They become organized into short piles that deepen in the underlying mesenchyme, enclosing the germinal cells in the process. Rapidly, the piles become confluent forming a compact mass, the gonadal blastema, which is soon cleaved into gonadal cords by stroma and vascular lacunae. The mesonephros becomes involved in the morphogenesis of the gonad only in late stages of development when anatomic continuities become established between the capsules of its regressing glomeruli and the elongating gonadal rete cords. These observations show that in the Galago the somatic cells of the gonadal blastema, i.e., the precursors of the definitive testicular and ovarian sustentacular cells, derive from the coelomic mesothelium in contrast to other mammals, e.g., ruminants and rodents, where they are of mesonephric derivation. This important point is discussed in light of the differences that exist among species with regard to the structural complexity, functionality, and stages of differentiation/involution of their mesonephroi on the one hand, and the time of gonadal development on the other.

Gametes contain angiotensin converting enzyme (kininase II).

The localization of angiotensin converting enzyme (ACE) in the gonads of the normal rabbit was studied by immunofluorescence and immunoelectron microscopy. The enzyme is present in the cytoplasm of testicular spermatids and of epididymal and ejaculated spermatozoa, and on the surface of follicular and tubal oocytes. These findings support the hypothesis that ACE has a role in gamete maturation and in fertilization.

Extracorporeal fertilization and embryo transfer in the treatment of infertility.

The study of human fertilization has assumed greater clinical importance as extracorporeal fertilization has been increasingly used to treat infertility. In vitro fertilization has advanced from years of struggle that preceded a single success to some programs that are able to establish pregnancy in a fifth or more of treatment cycles. The simpler procedure of donation of an early conceptus from an artificially inseminated female, now routine in animal husbandry, has only been recently accomplished in humans. With further refinements in methods of in vitro fertilization, virtually all women with an anatomically intact and healthy uterus may be able to establish a successful pregnancy.

Differentiation of mouse ectopic germinal cells in intra- and perigonadal locations.

Four hundred and thirteen ectopic germinal cells in the testicular and extratesticular stroma and in the rete testis of mouse fetuses from day 13 of uterine development to term were studied together with 161 ectopic germinal cells in the rete ovarii and periovarian stroma of female fetuses at days 17 and 18 of intrauterine life. The morphology and the differentiation of these ectopic germinal cells were compared to those of germinal cells within seminiferous and ovigerous cords. While the ectopic germinal cells in the testis and in the rete testis followed patterns of differentiation identical with those in the seminiferous cords throughout the period included in the study, those in the extratesticular stroma behaved like entopic germinal cells only through day 17, since at days 18 and 19 many of them entered meiotic prophase just like XX germinal cells in the ovigerous cords. No differences were noted between ectopic and entopic ovarian germinal cells. The results of this study show that the factors responsible for the male differentiation of XY germinal cells are not limited to the seminiferous cords but operate throughout the testicular territory, and confirm that outside the testis, XY germinal cells differentiate as female; our study also corroborates the thesis that the differentiation of XX germinal cells is an autonomous and ubiquitous process.

Germ cell differentiation in mouse adrenal glands.

The differentiation of germ cells in the adrenal glands of 26 male and female Swiss albino mice was studied in sequential stages of development, from day 12 1/2 of intrauterine life to postnatal day 21; the study was performed by means of high-resolution light microscopy and electron microscopy. In 12 1/2- and 13-day-old embryos, the ectopic cells had morphologic characteristics typical of primordial germ cells, whereas in 14- and 15-day-old fetuses they were identifiable as oogonia. In male and female fetuses from day 17 to term, all ectopic germinal elements entered meiotic prophase, reached diplotene, and differentiated into oocytes in perfect adherence to mouse ovarian timetables. In the postnatal animals, females as well as males, all oocytes progressed through the postmeiotic phase of growth just as they normally do in ovarian follicles, and, in the 2- and 3-week-old animals, they displayed features identical to those exhibited by oocytes in large antral follicles, including a zona pellucida. Germinal elements were no longer seen in the adrenals of animals older than 3 weeks. Our study shows that mammalian germ cells are capable of developing even outside the gonads, and that in ectopic sites they all differentiate as oocytes irrespective of their genetic sex.

Ectopic germ cells: natural model for the study of germ cell sexual differentiation.

In the course of a study on the morphogenesis of the adrenal gland in random-bred Swiss albino mice, we noted the presence of ectopic germ cells in the adrenal cortexes and medullas in animals of both sexes, from day 12 1/2 of fetal development to postnatal day 12. Up to day 15 of fetal development, the cells exhibited characteristics of primordial germ cells. At day 17, and irrespective of the sex of the fetus, they all entered meiosis in synchrony with those in the ovary. Postnatally, in females as well as males, all ectopic germ cells displayed morphologic characteristics identical to those of young oocytes in unilaminar ovarian follicles. No germinal elements were seen in the adrenal glands past day 12 of life. Our study shows that mammalian germ cells are capable of undergoing sustained differentiation outside the gonads and that, in ectopic sites, they all differentiate into oocytes as they normally would in the ovary, even in males.

The contribution of the mesonephros to the development of the sheep fetal testis.

In this study, which was performed on 52 sheep fetuses aged 24 to 85 days, we examined the relationship between testicular development and the "giant" mesonephric nephron, a peculiar structure consisting of a large glomerulus and multiple tubules. The development of the testis occurred in two phases. The preparatory phase began at day 24 of gestation, evolved simultaneously with the involution of the glomerulus of the giant nephron, and was characterized by mobilization of the glomerular cells and by their colonization of the genital ridge. By day 31, a prominent mass of migrating mesonephric cells had developed; it extended uninterrupted from the giant glomerulus into the gonad where the mesonephric cells associated with the germinal cells forming the cellular template from which the testicular cords later became assembled. At complete involution of the glomerulus (day 52), the migratory mass implanted on the tubules of the giant nephron, which thus became continuous with the gonad. During the organizational phase, which began at day 29 with the formation of the tunica albuginea, the various components of this continuum became progressively organized along a testis-to-mesonephros direction into seminiferous cords, tubuli recti, the cords of the rete testis, and the ductules efferentes. These observations show that, in the sheep, the precursors of the Sertoli cells are mesonephric in origin, and that the genital tract proximal to the epididymis differentiates from a single mesonephric nephron.

Preliminary observations on the role of the mesonephros in the development of the adrenal cortex.

The interrelationship between mesonephros, adrenal cortex, and gonads was studied in 28- and 31-day old sheep fetuses by means of light microscopy on plastic sections. At these stages, the adrenal cortex is just beginning to develop and mesonephros is undergoing involution; its regression is accompanied by mobilization of cells from the glomerulus of a peculiar nephron situated in the proximal third of the organ, and referred to as "giant" because of its large size. The mobilized cells egress from this glomerulus organized in trabeculae, some of which reach the cranial extremity of the adrenal cortex while others coalesce into a prominent cellular formation which extends uninterrupted toward and into the developing gonads. In previous studies we have shown that the mesonephric cells which colonize the gonads differentiate into sustentacular and interstitial steroidogenic cells; the presence of an analogous cellular migration from the mesonephros to the adrenal cortex now suggests that also the adrenal cortical cells may be of mesonephric origin.