The winds of change: medical staff relations

Are hospital governing boards and medical staffs natural adversaries in the health care ecosystem, or are they partners in a common effort? Are they parallel but equal organizations with different roles and different points of view, or, eventually, must one emerge with authority over the other? This article discusses how medical staff/board relations are changing and the need for better communications between the two leadership groups.

Prenyl lipid formation in spinach chloroplasts and in a cell-free system of Synechococcus (Cyanobacteria): polyprenols, chlorophylls, and fatty acid prenyl esters

Isolated chloroplasts from spinach leaf cells, chloroplast subfractions, and a cell-free system of the cyanobacterium Synechococcus CCAP 6312 incorporated [1-(14)C]isopentenyl pyrophosphate in high yields into prenyl lipids. Products were polyprenols (C20, C45) chlorophylls, quinoid compounds, and fatty acid prenyl esters; prenyl pyrophosphates occurred in trace amounts, and carotenes were only formed to a limited extent in the Synechococcus system. The formation of fatty acid prenyl esters, which is described here for the first time, was found to occur in two different ways in the chloroplast system; by an acyl-CoA: polyprenol acyltransferase reaction associated with the envelope membranes and by a transesterification reaction from chlorophyll associated with the thylakoids. Endogenous fatty acid prenyl esters made up about 3% by weight of total lipids in spinach chloroplasts and were also found to be natural constituents of the cyanobacterial cells.

The effect of iron on in vitro decalcification of human tooth enamel

The effect of iron chloride on an in vitro acid attack of human enamel was studied. Slices of teeth were covered with varnish except for a window left on one of the enamel surfaces for exposure. The iron salt was used as a supplement to acid gel, or as pretreatment of the enamel surfaces before exposure to the pure gel. Differences in light transmission of the experimental and control specimen from the radiographs taken before and after immersion in the decalcifying media were assessed quantitatively. The increase in radio-opacity of the enamel sections incubated in the iron-containing acid media was attributed to a lower degree of enamel decalcification.

Simultaneous occurrence of idiopathic lipemic tears and massive seborrhea

A 42-year-old man had idiopathic lipemic tears and massive seborrhea. Recent investigations have shown that cholesterol and other lipids occasionally found in tears are produced by meibomian rather than lacrimal glands. The finding in this patient of hypersecretion by both sebaceous glands and meibomian glands, a sebaceous gland variant, suggests that a common mechanism may regulate secretory control of both of these glands.

Relaxin in the pregnant baboon: evidence for local production in reproductive tissues

We examined the nonluteal production of relaxin in the pregnant baboon. In experimental animals (n = 5), the corpus luteum-bearing ovary was removed in early pregnancy (days 25-30), and intact pregnant baboons served as controls. In both groups of baboons, peripheral, uterine, and ovarian venous blood samples and amniotic fluid were collected immediately before hysterotomy, which was performed late in pregnancy (days 139-142). After hysterotomy, samples of reproductive and control tissues were obtained (placenta, decidua, myometrium, fetal membranes, and omentum). Relaxin concentrations were determined in all samples using an antiporcine relaxin RIA. In unilaterally oophorectomized pregnant baboons, peripheral plasma levels of relaxin were below the limits of detection (less than 157 pg/ml) for 100 days following corpus luteum removal, while levels in control pregnant baboons were greater than 1000 pg/ml. Relaxin levels in uterine venous plasma were comparable to peripheral plasma levels in each group. Relaxin concentrations in amniotic fluid of both groups were below the limits of detection (less than 157 pg/ml). Relaxin was found in decidua, placenta, and myometrium in those pregnant baboons in which the corpus luteum-bearing ovary had been removed over 100 days earlier. This finding together with the absence of a relaxin gradient in uterine venous plasma and undetectable relaxin levels in amniotic fluid is a strong indication of local relaxin production in reproductive tissues without contribution to peripheral plasma levels.

Relaxin

The past decade has seen major advances in understanding the chemistry of relaxin. Sensitive radioimmunoassays have allowed description of the secretion patterns of relaxin in several species. It is likely that technical advances in the near future will provide significant quantities of human relaxin as well as monoclonal antibodies to various relaxins. These tools should clarify the physiological roles of relaxin, elucidate its mechanisms of action, and enable testing of human relaxin as a potentially useful pharmacological agent.

Phase-I trial of combination therapy with continuous-infusion MMPR and continuous-infusion 5-FU

Fourty-four evaluable patients were treated with 6-methylmercaptopurine riboside (MMPR) at a dose of 20 mg/m2/day X 5 by continuous IV infusion (days 1-5 and 5-fluorouracil (5-FU) on an escalating dose schedule of 300-1519 mg/m2/day X 5 by continuous IV infusion (days 2-6). Dose-limiting oral mucositis occurred at a 5-FU dose of 1,381 mg/m2/day; other toxicities included nausea, vomiting, diarrhea, skin rash, and occasional myelosuppression. A partial and a complete response were observed in two previously untreated patients with metastatic colon carcinoma given the highest 5-FU doses (1,381 and 1,519 mg/m2/day). Bone marrow phosphoribosyl pyrophosphate (PRPP) levels monitored after 24 h of MMPR treatment indicated increases of 7.8- and 9.2-fold those found prior to therapy.

The effect of an anti-insulin antiserum on human sperm motility

Inhibition of sperm motility by anti-relaxin antiserum has been previously reported. This effect may be secondary to a nonspecific effect of immunoglobulins binding to sperm or to a specific inhibition of relaxin activity at the sperm surface. The current investigation demonstrates that an anti-insulin antiserum does not inhibit sperm motility in the same system in which an anti-relaxin antiserum results in inhibition. This supports the hypothesis that the anti-relaxin antiserum effect is specific.

Effect of prolactin and relaxin on in vitro rat uterine contractions and prolactin interaction with relaxin

The balance between relaxin and prolactin has been suggested to be significant in the control of uterine activity during pregnancy. The current study was designed to determine the effect of rat prolactin on rat uterine horn segment contractility and its interaction with relaxin. Rat uterine segments mounted on a smooth muscle transducer were treated sequentially with prolactin and relaxin, and stimulated electrically. No stimulatory effect of prolactin was noted. Relaxin-inhibited uterine horn segment activity was not altered by prolactin. The reported stimulatory effect of prolactin may have been a pharmacologic effect of human prolactin on rat uterine horn segments, or may have resulted from contaminants in the preparations used.

Stimulation of human sperm cervical mucus penetration in vitro by relaxin

The effect of relaxin, a peptide hormone present in seminal plasma, on the penetration of cervical mucus by washed human sperm in vitro was studied. Penetration was analyzed by two methods. The total number of sperm per 100 X field at the 10-mm, 20-mm, and 30-mm points along a mucus-filled capillary tube was counted and the farthest distance 100 sperm and 5 sperm/100 X field penetrated the capillary tube was measured. These measurements were made at 30, 60, and 90 minutes. Treating washed sperm with physiologic concentrations of relaxin resulted in significantly increased sperm penetration as compared with sperm treated with albumin or buffer. Replacing seminal plasma to washed sperm resulted in equivalently increased penetration. The findings strongly suggest that relaxin is necessary for proper penetration of cervical mucus by human sperm.

Relaxin in human decidua and term placenta

Using both a homologous porcine RIA and 3 bioassays, we investigated the relaxin content of human decidua from first trimester and term gestations and of placentas at term. Aqueous extracts of these tissues yielded only between 211 and 1090 pg immunoreactive relaxin/g fresh tissue. Neither acetonehexane extraction, octadecylsilica cartridge elution nor molecular sieve chromatography increased these relaxin levels. Compared with term decidua, first trimester decidua contained significantly higher levels of immunoreactive relaxin. In vitro studies did not evidence significant relaxin production by either decidual or placental tissues, even in the presence of decidual prolactin production. These results are in direct contrast to earlier reports of high concentrations of relaxin in decidua and placenta.

The effect of in vivo progesterone administration on relaxin-inhibited rat uterine contractions

Progesterone pretreatment in vitro was previously shown to sensitize myometrium to the inhibiting effect of relaxin. The following experiments were performed to control for possible artifacts of the in vitro system and to place these studies on a more physiologic basis. Immature rats were treated with estrogen and either progesterone or vehicle only. Uterine horn segments were isolated and mounted in a muscle bath. After a baseline contraction pattern was established by means of electrical stimulation, porcine relaxin was added to the bath. At all dose levels of relaxin, greater inhibition of contraction amplitude occurred in uterine segments of progesterone-treated animals. Since both progesterone and relaxin are present in the circulation from the time of the missed menses in human pregnancy, this interaction suggests a physiologic synergism in the maintenance of early human pregnancy.

Lectin target cells in human central nervous system and the pituitary gland

Peanut lectin (PNL), Concanavalin A (Con A) and Ulex europaeus lectin I (Ulex) were chosen to map their binding sites in different regions of formalin fixed and paraffin embedded human central nervous system tissue and pituitary gland tissues. An extended PaP method was used for PNL and Ulex, whereas a direct peroxidase technique was employed for Con A. In astrocytes, the cytoplasm as well as the delicate processes were stained by PNL and Con A; the most conspicuous binding of PNL was seen in the ependymal cells and on the surface of plexus epithelial cells; in the anterior part of the pituitary gland a selective population was PNL positive. Intracytoplasmic Con A acceptors could be demonstrated in neurons, in ependymal cells, and in plexus epithelial cells. Intracytoplasmic Con A receptors were finely granular in astrocytes, oligodendrocytes, and in some cells in the pituitary gland. Ulex binding was restricted to the vascular endothelial cells and a selective population of cells in the pituitary gland. Our results suggest that lectins may be good tools for the evaluation of their respective target cells in the central nervous system and in the pituitary gland.

Concanavalin A target cells in human brain tumours

Using a lectin-peroxidase method, Concanavalin A binding was examined on formalin-fixed paraffin-embedded biopsy specimens (n = 143) of the most frequent central nervous system tumours. The brain tumours included oligodendrogliomas, astrocytomas, glioblastomas, ependymomas, neurinomas, meningiomas, medulloblastomas and plexus papillomas. In oligodendroglioma cells, only a weak granular intracytoplasmic staining was observed. The astrocytomas showed a strong reaction in fibrillary astrocytes and in tumour areas undergoing small cystic degeneration. Staining of protoplasmic astrocytes was weaker; pilocytic astrocytes demonstrated poor perinuclear staining. Intracytoplasmic Con A binding in gemistocytic astrocytes was distinct but inconstant and rather diffuse. In the glioblastomas the lymphocyte-like small astrocytes were negative. Giant multinucleated astrocytes stained strongly. In ependymomas no or at most a weak perinuclear reaction was observed, whereas the acceptor density was as high as in the normal ependymocytes in areas where the tumour was capable of producing organotypical structures. Plexus papillomas showed a strong intracytoplasmic staining comparable to the normal plexus epithelial cell. This feature was preserved in the malignant variants. In general, meningiomas and neurinomas were negative. Xanthomatous-degenerated meningioma cells, however, showed a distinct to strong intracytoplasmic staining. This feature was characteristic for the xanthomatous subtype of meningiomas. Granular cells with strong intracytoplasmic Con A staining often occurred at the border of fibrillary to reticular differentiated areas of neurinomas. Medulloblastomas were completely negative. Our results indicate that Con A binding to human brain tumours is specific and rather cytotypical than histotypical . The Con A acceptor density is probably related to the grade of differentiation. Lectin mapping of tumours leads to cytotypical binding patterns which may contribute to the differential diagnosis of neoplasias.

Concanavalin A binding and neuronal differentiation. A light microscopic study on neuronal tumours

Concanavalin A (Con A) acceptors have been demonstrated in large differentiated neurons in a previous paper. In order to elucidate the correlation between Con A binding in normal and neoplastic neurons and lectin binding dependence upon the differentiation grade, 26 tumours of the neuronal series were examined using formalin fixed and paraffin embedded biopsy specimen. The neoplasms included 3 gangliocytomas, 7 gangliogliomas, 1 central neuroblastoma, 11 medulloblastomas, 2 retinoblastomas, and 2 sympathicoblastomas. Well differentiated neurons in gangliocytomas and gangliogliomas expressed a high intracytoplasmic Con A acceptor density comparable to the feature in large non-neoplastic neurons. Less differentiated neurons and neuroblasts showed a weak perinuclear fine granular binding or an absolute lack of binding molecules, respectively. Our results suggest that in a variety of tumours, Concanavalin A receptor density in neurons depends upon the degree of differentiation of the cell. Well differentiated cells have a higher density than poorly differentiated neoplastic neurons.

Relaxin

The author examines the investigative status of the peptide hormone relaxin, raising questions about and looking at the potential for the physiologic role of relaxin and the production of human relaxin for pharmacologic use.

Long-term outcome of hyperactive children

A review of outcome studies of hyperactive children suggests that they experience significant academic, social, and conduct difficulties during adolescence, and that social, emotional, and impulse problems persist into young adulthood for the majority. While some hyperactive children were found to be functioning normally as adults, a troublesome minority were experiencing severe psychiatric or antisocial problems.

Effect of anti-relaxin antiserum on sperm motility in vitro

Rabbit anti-relaxin antisera, but not normal rabbit sera, causes a rapid decline of motility of washed human sperm. Preincubation of the antisera with relaxin eliminates this effect. This sperm immobilization effect can serve as a basis of a rapid screening test for anti-relaxin antisera and as a novel adjuvant to barrier contraceptive methods.

The effect of relaxin and progesterone on rat uterine contractions

The effect of porcine relaxin on electrically stimulated in vitro contractions of isolated uterine horn segments from estrogen-pretreated immature rats was studied. Relaxin decreased the amplitude of contractions. A mean of 8.3 ng/ml of relaxin produced a 90% decrease in contraction amplitude. There was a minimal effect of 1.0 microgram/ml of progesterone on contraction amplitude. In vitro pretreatment of the isolated uterine segment with this dose of progesterone for 15 minutes did not significantly affect the dose of relaxin needed to decrease the amplitude of contractions. In contrast, pretreatment with progesterone for 45 minutes significantly decreased the concentration of relaxin needed to decrease contraction amplitude. Only 4.7 ng/ml of relaxin was needed to produce a 90% decrease in amplitude after progesterone pretreatment for 45 minutes (p less than 0.005). Relaxin and progesterone synergize in decreasing the amplitude of uterine contractions in vitro. A similar effect may occur in vivo.

Stimulatory effect of luteinizing hormone upon relaxin secretion by cultured porcine preovulatory granulosa cells

Relaxin, a peptide hormone capable of causing connective tissue alterations, is produced by the corpus luteum and traditionally considered a hormone of pregnancy. We have cultured granulosa cells from preovulatory porcine follicles and have found that these non-pregnancy associated cells secrete relaxin, and that luteinizing hormone, which stimulates ovulation, enhances relaxin secretion by cells from large preovulatory follicles. These results suggest that relaxin secreted prior to ovulation may have a local ovarian effect, perhaps facilitating ovulation.