Rapid and selective uptake, metabolism, and cellular distribution of docosahexaenoic acid among rod and cone photoreceptor cells in the frog retina

The uptake, metabolism, and cellular distribution of 3H-docosahexaenoic acid (3H-22:6) in the frog retina during in vitro incubation were studied. An initial diffuse labeling throughout the retina was detected by autoradiography and was followed by an active steady increase in labeled photoreceptor cells. After 6 hr of incubation, 92% of the label was concentrated in photoreceptor cells. Among these cells, 435-rods (green rods) labeled heavily and showed two to three times higher uptake than the 502-rods (red rods). Cone uptake labeling was the lowest, showing negligible labeling throughout the cytoplasm. However, oil droplets of the 575-cones actively concentrated 22:6. The high uptake of 3H-22:6 by photoreceptor cells was followed by its rapid esterification into phospholipids. After 6 hr of labeling, only 5% of the radioactivity in the retina was free 22:6, whereas 88% was esterified into phospholipids. The remaining 22:6 was distributed equally in triacylglycerols (TAGs) and diacylglycerols. When 3H-22:6 (0.11 microM) of high specific activity was used, early incubation times showed phosphatidylinositol (PI) labeling to be of the same order of magnitude or greater than that of phosphatidylcholine (PC) or phosphatidylethanolamine (PE). Although the amount of endogenous 22:6 esterified into PI accounted for less than 2% of the 22:6 in retinal phospholipids, 27% of 3H-22:6 labeling was recovered in this phospholipid. When 14C-22:6 at a final concentration of 70 microM was used, a different profile of lipid labeling was observed. Forty percent of the labeling remained in the free fatty acid pool, followed by TAG (24%), PC (14%), and PE (12%). PI showed the smallest increase in picomoles of 14C-22:6 incorporated, when compared with 3H-22:6. In conclusion, a selective and differential uptake of 3H-22:6 by photoreceptor cells is coupled to its active utilization for phospholipid biosynthesis, mainly that of PC, PE, and PI. The differential uptake of 3H-22:6 among photoreceptor cells may reflect involvement of this fatty acid in cell-specific functions.     

Breast cancer early diagnosis experience in Florence: can a self referral policy achieve the results of service screening?

STUDY OBJECTIVE--To assess the impact of a breast clinic on a specific target population and evaluate early diagnosis performance indicators for breast cancer in the presence of a self referral policy. DESIGN--Women living in Florence between 1980 and 1989 who had undergone mammography at a self referral breast clinic were studied. Main outcome measures were the use of mammography in relation to age, symptoms, and the interval between two subsequent tests, and early diagnosis performance indicators were the detection rate (DR), the prevalence/incidence ratio, and the proportion of early detected cancers. Performance indicators were compared with those from formal screening programmes. SETTING--Florence, Italy. PATIENTS--All mammograms performed at the clinic from 1980-89 in 40-69 year old women living in Florence were examined (n = 42,226). Records included the date of birth and of the examination, the reason for testing (asymptomatic/presence of pain/presence of symptoms other than pain), and the TNM classification for breast cancer cases. MAIN RESULTS--The total number of mammograms performed per annum increased by 70% over the decade, but much of this was routine repeat mammography (54.1% in 1989). Rates of first examinations in asymptomatic women increased in the second half of the decade from 17 per 1000 in 1985 to 31 per 1000 in 1989. Mammographic coverage decreased with increasing age from 12.6% in 40-49 year olds to 6.0% in 60-69 years old. Performance indicators of the activity in asymptomatic women were comparable with those expected in service screening. The proportion of not advanced cancers detected in asymptomatic women was 62.3% with a DR of 5.3 per 1000, and the average prevalence/incidence ratio was 2.9. CONCLUSIONS--High quality mammography performed in a breast clinic in self referred asymptomatic women can achieve as good results as a formal invitation screening service. Only a few of these women will benefit, but those who do are likely to be younger (40-49 year old women).     

Impairments in vasopressin-stimulated inositol lipid metabolism in hepatocytes of septic rats

Vasopressin (VP)-stimulated 32P-inositol lipid metabolism was studied in hepatocytes obtained from rats rendered septic by cecal ligation and puncture. Basal 32P-phosphatidylinositol (PI) labeling, as well as its hormone-stimulated turnover, were greatly reduced in septic rats compared with sham-operated rats. The earliest VP-induced degradation of 32P-polyphosphoinositides (poly-PI) was greatly attenuated in septic rats. Moreover, while 32P-poly-PI labeling reached its lowest value by 60 sec of VP stimulation in cells from sham-operated rats, maximal changes in 32P-phosphatidylinositol 4,5-bisphosphate (32PIP2) occurred within 30 sec in septic rats. In contrast, the recovery of 32PIP2 labeling was more active in cells from septic rats, overcoming the impairment in its resynthesis triggered by surgical trauma in cells from sham-operated rats. The lower uptake of 32P into phosphatidic acid (PA) at the different time points analyzed was a sensitive indicator of the lower production of diacylglycerols from the VP-induced degradation of inositol phospholipids in septic rats. These observations support the idea that sepsis is associated with perturbations in the earliest events of the hepatocyte signal transmission pathway, namely, at the level of a receptor coupled to inositol lipid metabolism. Such perturbations are likely to be involved in the previously reported defective cell physiologic response to external hormone stimulation.     

Term delivery in a woman with severe congenital neutropenia, treated with growth colony stimulating factor

The patient was diagnosed in childhood as having severe congenital neutropenia and had recurrent admissions with severe infections. In 1987, prior to getting married, she was sterilized. She continued to require i.v. antibiotics when she contracted a severe infection. On one occasion, she was treated with growth colony stimulating factor (G- CSF). Her increased neutrophil count was sustained following this treatment. In June 1993, she wished to start a family and underwent in- vitro fertilization (IVF) treatment. G-CSF was given prior to oocyte retrieval. She conceived on her first cycle and an ultrasound scan revealed a singleton pregnancy. Throughout the course of the pregnancy, her white cell count was monitored closely and remained at <1.0x10(9)/l. The pregnancy progressed uneventfully and at 37 weeks gestation she was admitted for G-CSF injections. At 38 weeks she was delivered of a boy weighing 3350 g, by elective Caesarean section. His white cell count was normal. This is the first case of G-CSF being used before conception and during pregnancy in a patient with congenital neutropenia. It shows that advances in cytokine therapy and close interdisciplinary liaison can lead to a successful outcome and help patients, who would otherwise remain childless, to achieve a family.      

Distribution of spermatogenesis in the testicles of azoospermic men: the presence or absence of spermatids in the testes of men with germinal failure [published erratum appears in Hum Reprod 1998 Mar;13(3):780]

The aim of the study was to determine whether a prior diagnostic testicle biopsy can predict success or failure of testicular sperm extraction (TESE) with intracytoplasmic sperm injection (ICSI) in patients with non-obstructive azoospermia caused by testicular failure, and what is the minimum threshold of sperm production in the testis which must be surpassed for spermatozoa to reach the ejaculate. Forty- five patients with non-obstructive azoospermia caused by testicular failure underwent diagnostic testicle biopsy prior to a planned future TESE-ICSI procedure. The diagnostic testicle biopsy was analysed quantitatively, and correlated with the quantitative findings of spermatogenesis in patients with normal spermatogenesis, as well as with the results of subsequent attempts at TESE-ICSI. Men with non- obstructive azoospermia caused by germinal failure had a mean of 0-6 mature spermatids/seminiferous tubule seen on a diagnostic testicle biopsy, compared to 17-35 mature spermatids/tubule in men with normal spermatogenesis and obstructive azoospermia. These findings were the same for all types of testicular failure whether Sertoli cell only, maturation arrest, cryptorchidism, or post-chemotherapy azoospermia. Twenty-two of 26 men with mature spermatids found in the prior testis biopsy had successful retrieval of spermatozoa for ICSI, 12 of their partners became pregnant, and are either ongoing or delivered. The study suggests that 4-6 mature spermatids/tubule must be present in the testis biopsy for any spermatozoa to reach the ejaculate. More than half of azoospermic patients with germinal failure have minute foci of spermatogenesis which are insufficient to produce spermatozoa in the ejaculate. Prior diagnostic testicle biopsy analysed quantitatively (for the presence of mature spermatids) can predict subsequent success or failure with TESE-ICSI. Incomplete testicular failure may involve a sparse multi-focal distribution of spermatogenesis throughout the entire testicle, rather than a regional distribution. Therefore, it is possible that massive testicular sampling from many different regions of the testes may not be necessary for successful TESE-ICSI.      

Adhesion inhibitory activity of β-lactoglobulin isolated from infant formulae

β-Lactoglobulin was isolated from infant formulae that were ultra high temperature (UHT) -treated, sterilized or spray-dried. The effect of the isolated β-lactoglobulin on SfaII-fimbriae-mediated adhesion of Escherichia coli to human ileostomy glycoproteins was studied in vitro. β-Lactoglobulin isolated from sterilized formulae was found to perform significantly less well than preparations from spray-dried formulae (p = 0:05). Great heterogeneity was observed in the adhesion inhibitory capacity of β-lactoglobulin isolated from UHT-treated formulae. Therefore, no significant difference was observed between UHT-treated and sterilized formulae or spray-dried formulae (p < 0:10). It can be hypothesized that β-lactoglobulin from spray-dried and some UHT-treated infant formulae may affect the colonization of mucous membranes by E. coli strains causing neonatal septicaemia and meningitis.