Behavioural and physiological adaptations to a burrowing lifestyle in the snake blenny, Lumpenus lampretaeformis, and the red band-fish, Cepola rubescens

Observations have been made on the mode of burrow construction in the snake blenny, Lumpenus lampretaeformis , under laboratory conditions. It appears that head probing and lateral oscillations of the body are principally responsible for the excavation of the burrow which is completed within 24 h. The burrow structure has been analysed in detail, showing a mean depth of 7.2 cm with a maximum observed length of 73 cm, with most systems between 20 and 35 cm in length. Initially linear burrows with two openings are usually provided with a small side tunnel, giving the system a characteristic Y-shape.
Burrow irrigation was investigated for the first time in L. lampretaeformis. The mean duration of burrow irrigation, by flexions of the tail of the fish, was 21 s with over 13 min h⁻¹ spent in irrigating the burrow. The mean water displacement per irrigation period was 3.1 ml. The PO ₂ and PCO ₂ were measured in both surface water and within the burrow system of L. lampretaeformis. Surface water values for PO ₂ were high (> 150 Torr) and PCO ₂ low (<0.4 Torr). Hypoxic and hypercapnic conditions were measured in the burrow system itself, with PO ₂ values ranging between 57 and 129 Torr and PCO ₂ rising to > 1.3 Torr in some burrows.
A comparative study of Cepola rubescens burrows indicated similar surface water PO ₂ and PCO ₂ values as in L. lampretaeformis. Burrow water PO ₂ values ranged between 60 and 94 Torr, with PCO ₂ values as high as 1.5 Torr being recorded. These results are discussed in relation to the adaptation of both species to a burrowing lifestyle.     

Acidosis facilitates spontaneous sarcoplasmic reticulum Ca2+ release in rat myocardium

Previous studies have shown that acidosis increases myoplasmic [Ca2+] (Cai). We have investigated whether this facilitates spontaneous sarcoplasmic reticulum (SR) Ca2+ release and its functional sequelae. In unstimulated rat papillary muscles, exposure to an acid solution (produced by increasing the [CO2] of the perfusate from 5 to 20%) caused a rapid increase in the mean tissue Cai, as measured by the photoprotein aequorin. This was paralleled by an increase in spontaneous microscopic tissue motion caused by localized Ca2+ myofilament interactions, as monitored in fluctuations in the intensity of laser light scattered by the muscle. In regularly stimulated muscles, acidosis increased the size of the Ca2+ transient associated with each contraction and caused the appearance of Cai oscillations in the diastolic period. In unstimulated single myocytes, acidosis depolarized the resting membrane potential by approximately 5 mV and enhanced the frequency of spontaneous contractile waves. The small sarcolemmal depolarization associated with each contractile wave increased and occasionally initiated spontaneous action potentials. In regularly stimulated myocytes, acidosis caused de novo spontaneous contractile waves between twitches; these waves were associated with a decrease in the amplitude of the subsequent stimulated twitch. Ryanodine (2 microM) abolished all evidence of spontaneous Ca2+ release during acidosis, markedly reduced the acidosis-induced increase in aequorin light, and reduced resting tension. We conclude that acidosis increases the likelihood for the occurrence of spontaneous SR Ca2+ release, which can cause spontaneous action potentials, increase resting tension, and negatively affect twitch tension.     

Biologic-response-modifier-induced indoleamine 2,3-dioxygenase activity in human peripheral blood mononuclear cell cultures

Degradation of tryptophan to kynurenine, catalyzed by indoleamine 2,3-dioxygenase (IDO), has been augmented in human epithelial cell lines treated with human interferon-gamma (HuIFN-gamma). Several human biologic response modifiers, including HuIFN-gamma, HuIFN-beta, HuIFN-alpha, interleukin 2 (HuIL-2), and tumor necrosis factor alpha, have now been assessed for their ability to enhance tryptophan degradation in human peripheral blood mononuclear cell (PMC) cultures. PMC were isolated from normal donors, cultivated in RPMI 1640 medium containing [3H]tryptophan, and treated with individual biologic response modifiers. At various intervals, culture supernatants were removed, fractionated by reversed-phase high performance liquid chromatography, and radioactivity in resultant fractions was determined. Significantly increased amounts of tryptophan catabolites were observed after treatment with HuIFN-gamma, HuIFN-beta, HuIFN-alpha, and HuIL-2, but not human tumor necrosis factor alpha. Often, greater than 30% of available tryptophan was degraded by treated PMC cultures. Although antibodies to HuIFN-alpha, HuIFN-beta, and HuIFN-gamma specifically neutralized the induction of IDO activity in PMC by their respective HuIFN, only anti-HuIFN-gamma antibody also neutralized HuIL-2-induced IDO activity. Furthermore, T24 bladder carcinoma cells, in which IDO was induced by HuIFN-gamma but not by the other biologic response modifiers, were induced to degrade tryptophan by supernatants of HuIL-2-stimulated PMC cultures, but not by HuIFN-beta-stimulated PMC culture supernatants. Thus, whereas HuIL-2 indirectly induced IDO in PMC cultures by stimulating production of HuIFN-gamma, all cases of interferons appeared to induce IDO directly in PMC cultures.     

Measurement of Acetylcholine Release in Freely Moving Rats by Means of Automated Intracerebral Dialysis

The present study demonstrates the feasibility of measuring acetylcholine in perfusion samples collected by means of in vivo brain dialysis in the striata of freely moving rats. The output of the dialysis device was directly connected to an automated sample valve of a HPLC-assay system that comprises a cation exchanger, a post-column enzyme reactor, and an electrochemical detector. The presence of an acetylcholinesterase inhibitor (neostigmine) in the perfusion fluid was required for the detection of acetylcholine in the perfusate. Increasing concentrations of neostigmine induced increasing amounts of acetylcholine. Continuous perfusion with a fixed concentration (2 microM) of neostigmine resulted in gradually increasing amounts of collected acetylcholine over time although a considerable variation between successive samples exists. The brain dialysis technique was further validated by studying the effect of various drugs. Systemically administered atropine increased the output of acetylcholine, whereas the addition of tetrodotoxin to the perfusion fluid resulted in a complete disappearance of the neurotransmitter.     

Retrospective evaluation of gynecologic cytodiagnosis. II. Interlaboratory reproducibility as shown in rescreening large consecutive samples of reported cases

Two laboratories exchanged and rescreened a large sample of cases with cervicovaginal smears they had consecutively accessioned to examine the reproducibility of gynecologic cytodiagnosis under optimum conditions. At least a "working agreement" (diagnoses within +/- 1 category on a ten-category scale) was achieved in diagnoses of normal, benign reaction and squamous abnormality (from minimal dysplasia though invasive cancer) in 18,859 cases (96.8%), of endometrial abnormality in 21 cases (42%) and of "unsatisfactory" in 99 cases (20.7%). Larger differences occurred in greater than or equal to 30% of cases except in the categories of "normal" and "benign reaction," reaching a maximum of 82% for moderate dysplasia. Reexamining 382 cases decreased disagreement by category to the 20% to 65% range only in the five categories of dysplasia plus carcinoma in situ. Agreement was not predicated on the presence of endocervical cells or squamous metaplasia; the basis for "unsatisfactory" calls was not uniform. Comparison of the laboratories' diagnoses with referee diagnoses or, on 178 cases, with tissue diagnoses also demonstrated differences in diagnostic criteria.     

Structural and dynamic properties of a bromouracil-adenine base pair in DNA studied by proton NMR

We have synthesized and studied by proton NMR a duplex heptaoligonucleotide containing a 5-bromouracil (brU)-adenine base pair. This represents the first structural characterization of a B-form DNA containing brU. The brU.A base pair is Watson-Crick rather than Hoogsteen as seen for the monomers in the crystalline state. From analysis of the NOESY sepctra at very short mixing times evidence is presented that substitution of brU for T induces significant conformational changes from that of a normal B DNA. The helix twist between brU4.A11 and G3.C12 is ca. 15 degrees and for both brU4 and G3 the glycosyl torsion angles are significantly changed. The imino proton of the bru.A base pair shows a pH insensitive line with which shows that the pK of brU in this base pair is very much higher than that of the monomer.     

Plasma uric acid levels in ethanol-fed turkey poults treated with allopurinol

Plasma uric acid levels were determined in ethanol-fed poults following administration of allopurinol. In young poults, allopurinol at a dose of 50 mg/kg significantly depressed plasma uric acid levels 6 hr post-dosing. At 11 hr post-dosing, plasma uric acid levels were significantly elevated in the allopurinol-treated poults when compared with control poults. During a period of ethanol abstinence, allopurinol at a dose of 40 mg/kg significantly depressed plasma uric acid levels up to 8 hr post-dosing. At a dose of 30 mg/kg, plasma uric acid levels were similar to control values at 4 and 6 hr post-dosing. Data suggest that plasma uric acid levels can be depressed in ethanol poults when allopurinol is administered every 8 hr at a dose of 40-50 mg/kg of body weight.     

Measurement of the transit time for cells through the epidermis and stratum corneum of the mouse and guinea-pig

Abstract A new approach to determine the transit time through the epidermis is presented, involving a gentle washing of the skin surface to collect the loosely attached surface corneocytes. This, it is believed, will be less likely to stimulate the system than tape-stripping or scraping. Radioactively labelled thymidine and iododeoxyuridine have been used to label cells in the basal layer and various labelled amino acids (glycine, cystine and methionine) have been used to label the metabolically viable cell layers (up to and including the granular layer). The resulting changes in surface radioactivity levels have been interpreted to provide a basal to surface transit time of 8–9.5 days for hairless and haired mouse epidermis and about 13.5 days for guinea-pigs. The basal to granular layer transit time, which probably includes some basal layer residence time, is about 4.5 days in the mouse and 8 days in the guinea-pig. The granular to surface time in mice is about 5 days. The results also suggest that when nuclear and cytoplasmic organelles are degraded in the granular layer, material is released that can diffuse rapidly through the stratum corneum to the surface. Some of this can be shown by chromatography to be thymidine. Hence, the stratum corneum is pervious to molecules such as nucleosides. This rapid diffusion outwards through the skin can also be detected shortly after injecting [¹²⁵I]-iododeoxyuridine.     

Lactose malabsorption in Polynesian and white children in the south west Pacific studied by breath hydrogen technique.

Lactose malabsorption was studied by a breath hydrogen technique in 139 Samoan and 68 white schoolchildren. The Samoans were studied in four locations, two in Western Samoa and two in New Zealand, and the white children in both the Cook Islands and New Zealand. The prevalence of malabsorption varied with location: for Samoans it ranged from 41% to 60% in Western Samoa and 0% to 35% in New Zealand; white children had rates of 27% in the Cook Islands and 5% in New Zealand. Environmental factors rather than genetic factors are likely to play the main part in initiating if not perpetuating lactose malabsorption. In both races lactose malabsorption had no effect on the acceptance of, consumption of, and number of gastrointestinal symptoms caused by milk and milk biscuits. Children who had symptoms after consuming a particular dairy product were more likely to say they disliked it than those who reported no symptoms.     

An antibody to the receptor for insulin-like growth factor I inhibits the growth of MCF-7 cells in tissue culture

Alpha IR-3, a monoclonal antibody to the insulin-like growth factor I receptor which blocks insulin-like growth factor I binding and inhibits its activity, inhibits the binding of 125I-insulin-like growth factor I to MCF-7 cells (an estrogen dependent human breast carcinoma cell line) with an IC-50 of approximately 100 ng/ml. It also inhibits the growth of MCF-7 cells cultured in 5% calf serum with approximately the same IC-50. Inhibition of growth occurs both when cells are cultured in the presence and absence of estrogen and is more pronounced when cells are grown at a low density. These findings demonstrate a requirement for insulin-like growth factor I for optimal growth of MCF-7 cells and suggest that it is an autocrine growth factor in these cells.