Cloning, characterization, and development expression of a rat lung alveolar type I cell gene in embryonic endodermal and neural derivatives

We report here the identification and characterization of a novel gene, T1 alpha, expressed in high abundance in adult rat lung, fetal lung, and early fetal brain. T1 alpha was identified by a monoclonal antibody previously shown to be specific for an antigen expressed by alveolar epithelial type I cells. The cDNA for T1 alpha is 1.85 kb and identifies a single mRNA species of the same size on Northern blots of adult rat lung. The longest open reading frame of the cDNA is 498 bases which would encode a protein of approximately 18 kDa. The protein has a putative membrane spanning domain near the C-terminus but lacks consensus sequences for N-glycosylation. Northern blots and RT-PCR show high expression of T1 alpha in adult lung, with marginally detectable expression in adult brain, intestine, and kidney. RT-PCR analysis shows expression of T1 alpha in freshly isolated type I cells (50-60% purity) but not in highly purified type II cells or other lung cells. We believe therefore that T1 alpha is primarily if not uniquely expressed in alveolar type I cells in the adult rat. Polyclonal antisera against a 16-amino-acid peptide identified in the deduced sequence reacts with the apical membranes of adult type I cells in lung tissue sections but does not label other cell types. The above antiserum as well as the original monoclonal antibody recognize a single approximately 18-kDa protein derived from bacterial expression of a construct containing the T1 alpha open reading frame. By RT-PCR T1 alpha is detected in rat lung from Day 13.5 onward, but is detected by in situ hybridization earlier in lung, brain and neural derivatives, and foregut. Expression is down-regulated in all but lung tissues as development proceeds.

The effects of spatial filtering and contrast reduction on visual search times in good and poor readers

Recent experiments with reading disabled children have shown that image blurring (produced with frosted acetate overlays) results in an immediate benefit in search performance, eye movement pattern and reading comprehension. This suggests that the contrast and spatial frequency content of visual stimuli are important factors for these children. In the present experiment, spatial frequency filtering and contrast reduction were employed to determine whether either of these factors contributes to the beneficial effects observed. Letter arrays were spatially filtered to produce low pass (< 3.5 c/deg) and high pass (> 7.0 c/deg) images. In addition, a low contrast control image was generated to match the low contrast of the high pass image. Children classified as good reader controls (CON), specific reading disabled (SRD), attention deficit disordered (ADD) or comorbid SRD/ADD (COM) were asked to perform a visual search task with each type of image. With high contrast, unfiltered arrays, the search times for the CON and ADD groups were much shorter than those of the SRD and COM groups. While both high pass and low pass filter conditions improved the search speed for the COM group, improvement for the SRD group was only obtained with low contrast stimuli. These results support the notion that the beneficial results of image blurring with SRDs derives from the contrast reduction produced by such manipulations.

Maximizing morphologic data from lung biopsies from normal and asthmatic humans

Obtaining lung biopsies from human patients is important because information gained from studies of the lung cells, tissue, and molecules is useful for both diagnosis and research. Because of their value these specimens should be handled carefully and analyzed with the best procedures available. Two morphologic techniques, immunocytochemistry and in situ hybridization, are particularly useful because they are sensitive and yield highly specific information. When combined with analysis of mRNAs by the reverse transcription-polymerase chain reaction, biochemical and morphologic data can be obtained from these small specimens. Multidisciplinary approaches such as these are proving to be very promising approaches to understanding asthma.

Modulators of prostaglandin E2 synthesis in human amnion

OBJECTIVE

The purpose of these studies was to determine the effects of the essential fatty acid, linoleic acid, and the commonly used non-steroidal anti-inflammatory agents, aspirin and acetaminophen, on the rate of prostaglandin (PG) biosynthesis by human amnion cells.

METHODS

Amnion cells were isolated from term, normal pregnancies and grown to confluence. Cells were incubated with control or medium containing 100 mumol/L linoleic acid. Cells were also incubated with control medium or medium containing 10 or 100 micrograms/mL aspirin or acetaminophen.

RESULTS

Following an initial delay, amnion cells exposed to linoleic acid exhibited a significant increase in PGE synthesis. Both aspirin and acetaminophen in clinically relevant concentrations had a significant inhibitory effect on amnion cell PGE synthesis.

CONCLUSIONS

Linoleic acid has a stimulatory effect and aspirin and acetaminophen have an inhibitory effect on PGE synthesis in human amnion cells in culture. We speculate that dietary habits, supplement ingestion, and over-the-counter drug use may affect amnion cell PG production. In view of the potential importance of intrauterine PG production in normal and abnormal labor, further study in this area is indicated.

A hydrodynamic interpretation of crisis in sickle cell anemia

The occurrence of crisis events in patients with sickle cell disease is associated with an increase in blood plasma viscosity, the hydrodynamic consequences of which are examined here. A mathematical model of the flow of sickle cells in capillaries predicts that for moderate increases in plasma viscosity, a regime of multivalued solutions for blood velocities is encountered, and the likely physical response is a precipitous drop to the lowest velocity solution. This behavior results from the coupling of the hydrodynamics with sickle erythrocyte rheology and oxygen transport to the surrounding tissue; no such catastrophe is predicted for normal erythrocytes. The type of velocity changes predicted by the model strongly suggest that plasma viscosity changes may play an important role in initiating or exacerbating crisis.

[Suspected inherited granulocytopathy in four Holstein Friesian calves]

Five Holstein Friesian calves varying in age from 7 to 9 weeks old, were suspected of suffering from an inherited granulocytopathy known as bovine leucocyte adhesion deficiency (BLAD). Four of them were examined clinically and at necropsy. The most significant clinical findings were fever, depression, weakness, emaciation, diarrhoea, pseudomembranous gingivitis, loose teeth, respiratory infection and occult blood in the faeces. Significant clinicopathological findings were marked leucocytosis, mainly due to a neutrophilia, hypoalbuminemia, hypogammaglobulinemia, increased alpha- and beta-globulins, elevated alkaline phosphatase enzyme activity, hypoglycaemia, and decreased blood urea concentrations. The necropsy revealed emaciated carcasses, granulomatous to necrotising gingivitis, pseudomembranous to necrotising enteritis with perforations, bronchopneumonia, splenic atrophy, and hypoplasia of the thymus. Histopathological examination supported the macroscopic findings.

The cupruretic effect of two chelators following copper loading in sheep

The cupruretic effect of 2 copper chelators, d-penicillamine and trientine, was assessed in 12 fistulated South African Mutton Merino rams of approximately 6 mo age following copper loading. Each animal received 20 mg CuSO4.5H(2)0/kg body mass as an 0.5% m/v aqueous solution, intraruminally, daily for 35 d. The animals were randomly assigned to either a d-penicillamine (n = 4) or trientine treatment group (n = 4) or an unmedicated control group (n = 4). A separate group of 3 rams were kept as non-copper-loaded controls. Urinary copper excretion was measured before and during treatment. All the sheep were housed individually or placed intermittently on steel metabolic crates to facilitate urine collection. At the end of the trial the animals were euthanatized and specimens of organs collected for determination of copper concentrations. d-Penicillamine significantly (p < 0.05) increased urinary copper excretion. Trientine failed to increase copper excretion in the urine when compared to the unmedicated and non-copper-loaded control groups.

Premature luteinization in controlled ovarian hyperstimulation has no adverse effect on oocyte and embryo quality

OBJECTIVE

To determine if premature luteinization has an adverse effect on oocyte and, hence, embryo quality.

DESIGN

Retrospective evaluation of anonymous ovum donors/oocyte recipients.

SETTING

A large oocyte donation program.

PATIENTS, PARTICIPANTS

Sixty-eight women undergoing controlled ovarian hyperstimulation (COH) as ovum donors were matched to 68 women with ovarian failure as ovum recipients who had endometrial maturation exogenously controlled by an identical hormone replacement protocol.

INTERVENTIONS

Serum was collected for E2 and P in donors and recipients.

MAIN OUTCOME MEASURES

The incidence of premature luteinization was determined in donors. Cycle characteristics were compared between donors with and without premature luteinization, with emphasis on oocyte and embryo quality. Implantation rates per embryo and delivery rates per transfer were measured in recipients.

RESULTS

Twenty-one (31%) of the donors demonstrated premature luteinization. Serum P was higher on day before hCG, day of hCG, and day after hCG in women demonstrating premature luteinization. However, there were no differences between donor cycles with or without premature luteinization as determined by donor age, ampules of gonadotropins used, day of hCG administration, peak E2, total number of oocytes, and number of mature oocytes retrieved. Ovum recipients were of similar age and had similar E2 exposure (area under the E2 curve) before P administration. Similar fertilization rates, incidence of polyspermia, number of embryos transferred of similar embryo grade, and similar implantation rates and deliveries per transfer were observed in women receiving oocytes from donors with and without premature luteinization, respectively.

CONCLUSIONS

Similar oocyte quality, fertilization, and polyspermia rates, embryo quality, implantation, and delivery rates suggest that any negative impact of premature luteinization on pregnancy rates in COH cycles from young women is not due to an adverse effect of PL on oocyte and hence embryo quality, but rather on the endometrial environment.

Obstetric correlates of neonatal retinal hemorrhage

OBJECTIVE

To determine whether maternal or fetal factors, other than vacuum-assisted delivery, play a role in neonatal retinal hemorrhage, and whether correlates are similar in retinal hemorrhage after spontaneous vaginal delivery.

METHODS

A cross-section of assisted deliveries at an urban hospital (n = 156) over 7 months were compared with contemporaneous spontaneous vaginal deliveries (n = 122). A subset of assisted deliveries (n = 87) was prospectively randomized to forceps or vacuum-assisted delivery by sealed envelope. Maternal and neonatal biometric data were collected, and Apgar scores, umbilical artery blood gas analysis, and neonatal ophthalmologic evaluations were performed.

RESULTS

Moderate to severe retinal hemorrhage was found in 18% of spontaneous, 13% of forceps, 28% of vacuum-assisted, and 50% of sequential vacuum and forceps-assisted deliveries. Fetal distress (P < .008), vacuum-assisted delivery (P < .02), decreased birth weight for gestation (P < .004), umbilical artery pH less than 7.20 (P < .004), and second stage of labor less than 30 minutes (P < .05) were most closely associated with increased degrees of retinal hemorrhage. Maternal parity, preeclampsia, length of labor, and head circumference were not correlated with retinal hemorrhage. Vacuum-assisted delivery among low birth weight infants (P < .0001), short second stage of labor (P < .006), fetal acidosis (P < .045), and sequential use of vacuum and forceps for assisted delivery (P < .005) formed a logistic model that correctly predicted 81% of moderate to severe retinal hemorrhage cases. Logistic analysis of the randomized assisted deliveries gave similar results.

CONCLUSIONS

Maternal and fetal factors other than vacuum-assisted delivery are significant correlates of moderate to severe retinal hemorrhage. Vacuum-assisted delivery among small for gestational age infants is closely correlated with moderate to severe retinal hemorrhage.

Anaplastic tracheal squamous cell carcinoma in a cat

A cat with primary intratracheal squamous cell carcinoma presented with severe dyspnoea and a dry cough. Radiographic changes included pulmonary hyperinflation and tracheal thickening at the thoracic inlet. On post mortem examination, proliferative, white, granular nodules in the trachea were confirmed to be an anaplastic squamous cell carcinoma.

A longitudinal study of the effects on the oral mucosa of treatment for acute childhood leukaemia

A longitudinal study was undertaken of the effect of therapy on the oral mucosa of 12 children with acute leukaemia. The major oral problem was ulceration, which was associated with neutrophil counts of less than 1.0 x 10(9)/l. Candida carriage rates were consistently high in patients with or without oral candidosis. Salivary flow was not significantly different between leukaemic children and the control group.

Effects of surfactant apolipoproteins on liposome structure: implications for tubular myelin formation

Tubular myelin is one of several forms of lung surfactant and may play an important role in its surface activity. To determine possible mechanisms of tubular myelin formation, we studied the effects of purified surfactant proteins (SP-A, SP-B, and SP-C) on large unilamellar dipalmitoylphosphatidylcholine-egg phosphatidylglycerol (7/3; wt/wt) liposomes. We studied different types of membrane interaction induced by the apolipoproteins and correlated these with the observed changes in ultrastructure. Aggregation was assessed by measurement of light absorbance, lysis, and fusion by measurement of the fluorescence emitted by water-soluble and lipid-soluble probes, respectively. Mixtures of the apolipoproteins and liposomes were examined in ultrastructural studies by negative staining and by thin sectioning. We found that each protein had a pronounced and distinct effect on liposome structure. SP-A caused aggregation, whereas SP-B and SP-C also caused extensive leakage of liposome contents (lysis) and some degree of lipid mixing (fusion). The disruptive effects of SP-B and to a lesser extent those of SP-C were correlated by negative staining with the appearance of bilayer disks, which tended to aggregate into large sheets. There was a marked synergy between SP-A and SP-B in the process of membrane fusion in the presence of calcium, which correlated with an early (10 min) and extensive rearrangement of the structures seen by electron microscopy followed by a delayed (24 h) appearance of small amounts of tubular myelin.

Effective interventions for reading disability

A simple, readily accessible, and inexpensive intervention which produces immediate improvements in the reading comprehension abilities of reading-disabled children has been found. The intervention consists of colored overlays, or overlays which reduce the contrast of printed materials. This intervention produces reading comprehension gains in approximately 80 percent of the reading-disabled children tested.

A randomized comparison of assisted vaginal delivery by obstetric forceps and polyethylene vacuum cup

The assisted vaginal delivery methods of rigid obstetric forceps and polyethylene vacuum cup extraction were compared in a prospective, randomized study. The 99 women studied had all completed 35 full weeks' gestation, required attempted assisted vaginal delivery, and were randomly assigned to either attempted forceps or vacuum-assisted delivery. All presentations were cephalic, with stations ranging from +1 to +4. Neonates were evaluated at 24 hours by neonatal staff. The infants underwent intracranial ultrasound screening during the first 24 hours of life and ophthalmologic examination within 48 hours. Vaginal delivery was successful with the intended method in 83% of vacuum-assisted deliveries and in 78% of forceps deliveries (not statistically significant). Neonatal retinal hemorrhage was found in 17 and 38% (P less than .043) of the randomized forceps and vacuum deliveries, respectively. No intraventricular hemorrhage was found. Apart from associations between vacuum-assisted delivery and mild hyperbilirubinemia and neonatal retinal hemorrhage (of uncertain clinical significance), and between assisted forceps delivery and an increased potential for facial injury, neonatal outcomes did not differ significantly. Maternal outcomes also did not differ significantly. No significant differences in safety or efficacy were found between polyethylene cup vacuum extraction and rigid obstetric forceps-assisted vaginal delivery in this population of predominantly low-pelvic assisted deliveries. Patients delivered by sequential use of forceps after vacuum or by vacuum after failed forceps application did not suffer significantly increased morbidity relative to those delivered by forceps or vacuum alone. Use of alternate or sequential methods allowed an overall cesarean rate of 3% in this population.

Regulation of ATP-dependent surfactant secretion and activation of second-messenger systems in alveolar type II cells

Several different classes of agonists are known to stimulate exocytosis in type II cells. These agonists cause increases in second messengers, such as adenosine 3',5'-cyclic monophosphate (cAMP) or cytosolic Ca2+, and/or stimulate protein kinase C. We studied generation of cAMP and phosphoinositide (PI) turnover in monolayer cultures of type II cells and measured [Ca2+]i in single cultured cells. ATP [10(-4) M], which stimulates secretion of phosphatidylcholine (PC) and increases cellular cAMP, also stimulated PI turnover and increased [Ca2+]i. 12-O-tetradecanoylphorbol-13-acetate (TPA), which stimulates PC secretion and activates protein kinase C, did not increase [Ca2+]i. Pretreatment of type II cells with the calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) inhibited the PC secretion induced by ATP and TPA and blocked the increase in PI turnover caused by ATP. ATP-dependent surfactant secretion and stimulation of PI turnover could also be inhibited by pretreatment of the cells with pertussis toxin. We used the fluorescent probe indo-1 to measure [Ca2+]i in single cultured type II cells. ATP produced rapid transient increases in [Ca2+]i, which could be prevented by pretreatment of the cells with either TPA or W-7. Our data suggest that pertussis toxin-sensitive G protein(s) are involved in ATP-dependent activation of PI turnover and in secretion of surfactant in type II cells. Activation of protein kinase C blocks the ATP-stimulated increase in [Ca2+]i. Finally, calmodulin may be involved in the regulation of ATP-dependent increase in [Ca2+]i, the activation of PI turnover, and the secretion of surfactant in type II cells.

Sequential outpatient application of intravaginal prostaglandin E2 gel in the management of postdates pregnancies

A randomized blinded investigation was undertaken to determine the efficacy and safety of sequentially applied intravaginal prostaglandin E2 (PGE2) gel for accelerating cervical ripening in an outpatient setting in low-risk prolonged pregnancies. Fifty women with uncomplicated pregnancies at or beyond 41 weeks' gestation and Bishop scores below 9 received twice-weekly outpatient administration of gel containing 2.0 mg of PGE2 or placebo. Thirty nulliparas and 20 multiparas were enrolled. The PGE2 gel failed to improve cervical ripening over placebo, as judged by Bishop scores. There was no difference between the groups in gestational age on admission to the labor and delivery suite, number of gel applications, requirement for oxytocin, incidence of cesarean delivery, or neonatal outcome. Only two patients (4%) experienced regular uterine contractions after gel insertion; these subsided spontaneously in both. None of the subjects experienced labor, tetanic contractions, evidence of fetal distress, or any other side effects related to gel insertion. We conclude that PGE2 gel in this dosage may be used safely in an outpatient setting, but more frequent application or earlier initiation may be required to produce a clinical effect.

Changes in lipid structure produced by surfactant proteins SP-A, SP-B, and SP-C

Pulmonary surfactant phospholipids may assume several different structures including tubular myelin, unilamellar and multilamellar vesicles, and others. These populations of materials appear to have similar phospholipid compositions but may differ in their association with surfactant proteins SP-A, SP-B, or SP-C. We have used electron microscopy to determine the changes in structure of simple lipid mixtures (phosphatidylglycerol, dipalmitoylphosphatidylcholine) produced by adding one or combinations of the three proteins. Adding SP-A to lipids generated multilamellar structures composed of membranes with fuzzy or particulate surfaces. In contrast, SP-B or SP-C generated discoidal particles and structures that appeared to be sheets of membrane formed by associated particles. Used together, SP-A and SP-B reorganized some of the lipid into tubular myelin, a structure that was not observed in SP-A, SP-C recombinants. These observations confirm the in vitro formation of tubular myelin reported by others and support the possibility that surfactant materials with defined structure can be produced in vitro for analyses of their molecular organizations.

Differentiation of type II cells during explant culture of human fetal lung is accelerated by endogenous prostanoids and adenosine 3',5'-monophosphate

Explant culture of the fetal lung, in the absence of serum or hormones, results in precocious biochemical and morphological differentiation of alveolar epithelial cells. In this study we tested the hypothesis that these maturational events are induced by endogenous cAMP. During culture of human fetal lung the content of tissue cAMP increased 140% from days 3-6. Treatment with isobutylmethylxanthine caused a further doubling of cAMP content, and indomethacin blocked most of the increase in cAMP. Isobutylmethylxanthine accelerated and indomethacin inhibited the increases during culture in surfactant protein-A (SP-A), SP-A mRNA, SP-B mRNA, phosphatidylcholine content, and activity of fatty acid synthetase. There was no effect of these treatments on the content of SP-C mRNA, which did not increase during culture. Increasing concentrations of prostaglandins E1 and E2 in the presence of indomethacin produced a parallel stimulation of cAMP content, SP-A, and fatty acid synthetase activity. The temporal increase in SP-A was also blocked by inhibitors of protein kinase-A. In morphological studies, indomethacin-treated explants appeared less mature, with decreased intralumenal volume and more columnar epithelial cells. We conclude that increased tissue cAMP levels, stimulated by endogenous prostaglandins, accelerate differentiation of alveolar epithelial cells during explant culture.

Metacontrast with masks varying in spatial frequency and wavelength

In a metacontrast masking paradigm, adult subjects were required to detect briefly presented target lines followed at various delays by a flanking mask varying in spatial frequency and wavelength. Detection accuracy, the dependent measure, was recorded as a function of the delay of the mask. The results showed that long wavelength masks produced maximum masking at a relatively short delay, while short wavelength masks produced maximum masking at a relatively long delay. Results are discussed within the framework of transient/sustained (magnocellular/parvocellular) theory of visual processing, and suggest that low spatial frequency channels respond with shorter latency and/or faster rise time to short wavelength stimuli, and high spatial frequency channels respond with greater sensitivity to long wavelength stimuli.