The role of testosterone in the feedback control of male FSH and LH secretion

Summary Intramuscular administration of 250 mg testosterone oenanthate per week over a period of 21 weeks treatment rapidly and sustainedly suppressed serum LH as well as FSH levels in seven normal males, while serum testosterone rose by a factor of approximately two. These together with other data provide increasing evidence for a feedback control of FSH secretion by gonadal steroids in the male in addition to the already described but as yet undefined tubular testicular factor.     

Hyposmolarity-activated fluxes of taurine in astrocytes are mediated by diffusion

In order to obtain information about the mechanism responsible for swelling associated taurine release in astrocytes, the kinetics of taurine uptake in cultured astrocytes from mouse cerebral cortex was studied under isosmotic and hyposmotic (50% osmolarity) conditions. It was found that the V_max for the high affinity component of taurine uptake was unaffected by exposure of the astrocytes to hyposmotic conditions and that the K_m value was somewhat increased. Contrary to V_max, the non-saturable component of the uptake was greatly increased (2.5-fold) after exposure of the cells to hyposmotic media leading to cell swelling. In addition to the kinetic characterization of taurine uptake the actual intracellular taurine content after incubation (15 min) in isosmotic or hyposmotic media with different taurine concentrations (0–100 mM) under Na⁺-free conditions was determined. At taurine concentrations < 30 mM corresponding to the intracellular content in cells not exposed to taurine, exposure to hyposmotic media led to a decrease in the intracellular taurine content. At higher external taurine concentrations (> 30 mM) the intracellular taurine contents were dramatically increased after exposure to hyposmotic conditions. The increase in intracellular taurine seen under hyposmotic conditions at 100 mM external taurine could be significantly reduced by 100 μM DIDS (4,4′-diisothiocyanatostilbene-2,2′-disulfonate). Altogether these results suggest that a diffusional process rather than the high affinity taurine carrier is involved in the swelling induced increase in astrocytic taurine influx and efflux.     

Implantation, interception and contraception

The factors involved in post-fertilization events leading toimplantation in mammals are discussed with special referenceto potential forms of interception. The stages of embryonicgrowth until implantation are considered initially. The growthand differentiation of the uterine endometrium is then described,followed by the events occurring during the apposition and invasionof the implanting embryo. Several potential approaches to newforms of interception are considered, and the advantages anddisadvantages of each of them are evaluated. Among them, newvaccines against the zona pellucida, inactivation of the secretionsof the blastocyst, hatching, the activity of the pinopodes,and the endometrial proteins produced in the secretory phaseseem to offer various and varied targets. Some existing methodsof fertility regulation may act by affecting these stages ofdevelopment, e.g. RU486 may interfere with pinopod function.Various physiological and embryonic consequences of interferingwith these stages of pregnancy are discussed.     

Lipoblastoma and lipoblastomatosis in infancy and childhood: histopathologic, ultrastructural, and cytogenetic features

Lipoblastoma is a relatively rare tumor that occurs in infancy and early childhood and arises from embryonic white fat. Although a benign tumor, lipoblastomas tend to recur and may resemble myxoid liposarcoma. The authors report 26 cases over a 15-year period at Texas Children's Hospital. There was a slight female predilection (14F:12M). The most common symptom was a painless mass with or without increasing size. The trunk, extremities, head and neck, retroperitoneum, inguinal canal, peritoneal cavity, and lung were the tumor sites. Most tumors were circumscribed lipoblastomas and the minority were diffuse infiltrative lipoblastomatosis. Reexcision for residual or recurrent tumor was necessary more frequently in patients with lipoblastomatosis. Histopathologic examination and ultrastructural examination revealed cellular neoplasms composed of immature adipocytes with relatively well-defined septa, frequent lipoblasts, a fine vascular network, and often a myxoid appearance resembling myxoid liposarcoma. Cytogenetics was performed in 4 cases with chromosome 8q abnormality being most common. The major concern with lipoblastoma in children is to completely excise the tumor to avoid leaving residual tumor and to prevent recurrences. Confusion with myxoid liposarcoma, well-differentiated liposarcoma, and typical lipomas may occur. Although asymptomatic, lipoblastomas may cause dysfunction of other organ systems due to mass effect. Complete surgical excision with at least 2 years of follow-up is the preferred therapy.     

LH syndrome and brain catecholamine levels after lesions of the nigrostriatal bundle

Lesions of the nigrostriatal bundle (NSB), whose fibers pass through the medial portions of the internal capsule and the immediately adjacent lateral hypothalamus (LH), produced a more severe aphagia, adipsia, and disturbance of water regulation than did lesions of the medial forebrain bundle (MFB). When deprived of food, animals with NSB lesions drank significantly less than controls and animals with MFB lesions. NSB lesions also produced greater decreases in telencephalic content of the catecholamines than MFB lesions, while the reverse was true for serotonin. Water intake during food deprivation was highly correlated with telencephalic catecholamine levels in animals with NSB lesions. Thus, the inability to regulate water intake in the absence of food, one of the characteristic and long lasting effects of the LH syndrome, appears to be due to destruction of the NSB and the consequent decline in telencephalic content of catecholamines.     

Reproduction and thermoregulation in Peromyscus: Effects of chronic short days

Seven groups of laboratory reared Connecticut P. leucopus were exposed to a 9L:15D photoperiod for either 6, 9, 12, 20, 25, 32, or 36 weeks. An eighth group was maintained on 16L:8D. During the final 6 weeks all mice were cold exposed (13°C). Substantial reproductive regression occurred in females following 6 weeks exposure to 9L:15D relative to 16L:8D animals. In males, a slight decrease in testicular weight occurred following 6 weeks on 9L:15D; this effect was pronounced by 9 weeks, along with a decrease in seminal vesicle weight. Reproductive recrudescence occurred in females by week 32 and in males by week 36. Between 10 and 12 weeks on 9L:15D mice exhibited increases in nesting, incidence of daily torpor, and presence of the winter molt. These increases persisted through 36 weeks on 9L:15D. An increase in the interscapular brown fat pad occurred between 12 and 25 weeks. Reproductive and thermoregulatory characters respond differently to prolonged exposure to a short day photoperiod in this species.     

Regulation and selection of patients

During the past decades health legislation and regulation have been on the increase in most industrialized countries. The growing role of government in the provision and financing of health care, the need to correct given aspects of health care and the mandate to protect the underprivileged have been some of the many reasons for increased regulation. Different regulatory approaches and their respective advantages and disadvantages are reviewed in this paper. Particular attention is given to the crucial issue of how to regulate the access to scarce resources and how to cope within a legislative approach with the resulting patient selection.     

FAM19A4基因启动子甲基化检测在宫颈癌及其癌前病变筛查的研究

宫颈癌是最常见的妇科恶性肿瘤之一。目前人乳头瘤病毒(HPV)检测及细胞学检查是宫颈癌及其癌前病变(CCPL)的主要筛查手段。由于上述传统筛查方法,仍然存在对CCPL漏诊的风险,因此寻找有效识别CCPL的特异性分子标志物,具有重要临床意义。对具有序列相似性家族19成员A4(FAM19A4)基因启动子甲基化定量检测,可有效检出CCPL组织,较传统筛查方法有较高特异度,有望成为CCPL筛查的特异性分子标志物。笔者拟就FAM19A4基因启动子甲基化定量检测,在CCPL筛查中应用的最新研究现状进行阐述,旨在为进一步推进CCPL筛查方法的开发,提供思路。     

How defective spermatogenesis affects sperm DNA integrity

Spermatogenesis is the essential process to maintain and promote male fertility. It is extraordinarily complex with many regulatory elements and numerous steps. The process involves several cell types, regulatory molecules, repair mechanisms and epigenetic regulators. Evidence has shown that fertility can be negatively impacted by reduced sperm DNA integrity. Sources of sperm DNA damage include replication errors and causes of DNA fragmentation which include abortive apoptosis, defective maturation and oxidative stress. This review outlines the process of spermatogenesis, spermatogonial regulation and sperm differentiation; additionally, DNA damage and currently studied DNA repair mechanisms in spermatozoon are also covered.     

Scientific connotation of “treating different diseases with the same method” from the perspective of metabolic–immune dysregulation in inflammation-mediated carcinogenesis of digestive organs

Inflammation-mediated carcinogenesis develops in the context of chronic inflammation and is a significant cause of cancer within the digestive system. In the chronic inflammation microenvironment, the metabolic activity of tissue cells undergoes extensive changes, which interfere with the normal function of immune cells. Dysregulation of cell metabolism and immune function has been identified as a key factor contributing to inflammation-mediated carcinogenesis within the major digestive organs, such as the stomach, liver, and colorectum. This metabolic–immune imbalance also corresponds to traditional Chinese medicine (TCM) theories of “yin-yang disharmony” and “disharmony between Ying-nutrients and Wei-defense.” The metabolic–immune imbalance has also been regarded as the key factor supporting “treatment of different diseases with the same method,” in which the same approach is adopted in the treatment of different conditions. In the TCM treatment process, it is necessary to first identify TCM patterns and then apply the corresponding TCM to correct the dysregulated metabolic and immune function, thereby blocking the progression from inflammation to malignancy. Our study findings deepen the TCM understanding of metabolic–immune dysregulation and the relationship between metabolic–immune dysregulation, pattern identification, and treatment method. They also provide new insights for the treatment of inflammation-mediated carcinogenesis in major digestive organs and help us further explore the scientific connotation of the TCM strategy of “treating different diseases with the same method.