Intrinsic functional architecture in the anaesthetized monkey brain

The traditional approach to studying brain function is to measure physiological responses to controlled sensory, motor and cognitive paradigms. However, most of the brain's energy consumption is devoted to ongoing metabolic activity not clearly associated with any particular stimulus or behaviour. Functional magnetic resonance imaging studies in humans aimed at understanding this ongoing activity have shown that spontaneous fluctuations of the blood-oxygen-level-dependent signal occur continuously in the resting state. In humans, these fluctuations are temporally coherent within widely distributed cortical systems that recapitulate the functional architecture of responses evoked by experimentally administered tasks. Here, we show that the same phenomenon is present in anaesthetized monkeys even at anaesthetic levels known to induce profound loss of consciousness. We specifically demonstrate coherent spontaneous fluctuations within three well known systems (oculomotor, somatomotor and visual) and the 'default' system, a set of brain regions thought by some to support uniquely human capabilities. Our results indicate that coherent system fluctuations probably reflect an evolutionarily conserved aspect of brain functional organization that transcends levels of consciousness.

First experimental demonstration of self-synchronous phase locking of an optical array

A novel, highly accurate, all electronic technique for phase locking arrays of optical fibers is demonstrated. We report the first demonstration of the only electronic phase locking technique that doesn't require a reference beam. The measured phase error is lambda/20. Excellent phase locking has been demonstrated for fiber amplifier arrays.

Neural correlates of verbal memory encoding during semantic and structural processing tasks

Eighteen participants were imaged using fMRI to explore whether brain regions predicting successful verbal memory encoding during semantic decisions would continue to predict encoding during structural (non-semantic) decisions. Consistent with prior studies, left inferior frontal and fusiform regions were more active during semantic than structural decisions, and activity was greater for remembered than forgotten words during semantic decisions. Critically, structural decisions yielded significantly greater activity for remembered than forgotten words in these regions providing evidence that a common frontal-temporal network supports verbal memory encoding irrespective of orienting task. Further analysis revealed activity associated with successful encoding in the right precentral gyrus, suggesting other regions may also play a role in verbal encoding during non-semantic processing.

Effect of intense training on plasma leptin in male and female swimmers

PURPOSE

The purpose of this study was to determine whether fasting plasma leptin concentration was altered with an increase in training volume in competitive male and female athletes.

METHODS

Intercollegiate male (N = 9) and female (N = 12) swimmers were examined during the preseason and at two times during the mid-season (mid-season 1 and mid-season 2) when training volume was relatively high (33,000 m.wk(-1)). Body composition (hydrostatic weighing), energy intake and expenditure, and fasting plasma leptin concentration were measured.

RESULTS

In the women, there was a significant (P < 0.05) decline in fat mass (2 kg) with the increase in training volume, which was not accompanied by a reduction in fasting leptin (12.8 +/- 1.5 vs 11.0 +/- 1.2 vs 11.0 +/- 1.5 ng.mL(-1) for preseason, mid-season 1, and mid-season 2, respectively). In the men, there were no significant changes in body composition, body mass, or fasting leptin (4.4 +/- 0.8 vs 4.3 +/- 0.8 vs 4.6 +/- 0.8 ng.mL(-1), respectively).

CONCLUSION

These findings suggest 1) plasma leptin is not sensitive to an increase in training volume and 2) leptin may not be indicative of changes in fat mass with an increase in training volume in female athletes. These data suggest that leptin may not be useful in monitoring relative training stress in athletes.

Effects of pulsed electromagnetic fields on bone healing in a rabbit tibial osteotomy model

OBJECTIVE

The purpose of this study was to determine the effect of pulsed electromagnetic field (PEMF) exposure on healing tibial osteotomies in New Zealand White rabbits.

DESIGN

One-millimeter Gigli saw osteotomies were stabilized by external fixation. One day after surgery, rabbits were randomly assigned to receive either no exposure (sham control) or thirty minutes or sixty minutes per day of low-frequency, low-amplitude PEMF. Radiographs were obtained weekly throughout the study. Rabbits were euthanized at fourteen, twenty-one, or twenty-eight days, and tibiae underwent either destructive torsional testing or histologic analysis. To determine the baseline torsional strength and stiffness of rabbit tibiae, eleven normal intact tibiae were tested to failure.

RESULTS

Sixty-minute PEMF-treated osteotomies had significantly higher torsional strength than did sham controls at fourteen and twenty-one days postoperatively. Thirty-minute PEMF-treated osteotomies were significantly stronger than sham controls only after twenty-one days. Normal intact torsional strength was achieved by fourteen days in the sixty-minute PEMF group, by twenty-one days in the thirty-minute PEMF group, and by twenty-eight days in the sham controls. Maximum fracture callus area correlated with the time to reach normal torsional strength.

CONCLUSION

In this animal model, low-frequency, low-amplitude PEMF significantly accelerated callus formation and osteotomy healing in a dose-dependent manner.

Gaze direction modulates finger movement activation patterns in human cerebral cortex

We investigated whether gaze direction modified the pattern of finger movement activation in human cerebral cortex using functional magnetic resonance imaging (MRI). Participants performed a sequential finger-tapping task or made no finger movements while maintaining gaze in the direction of the moving hand (aligned conditions) or away from the location of the moving hand. Functional MR signals, measured in the hemisphere contralateral to the moving hand, revealed finger movement-related activation in primary motor cortex, lateral and medial premotor cortex, and a wide extent of the lateral superior and inferior parietal lobules. In each area, the extent of the finger movement activation increased when static gaze was more aligned with the moving hand compared to when gaze was directed away from the moving hand. These data suggest the existence of large-scale cortical networks related to finger actions and indicate that skeletomotor processing in the cerebral cortex is consistently modified by gaze direction signals.

Development of FlexSure HP--an immunochromatographic method to detect antibodies against Helicobacter pylori

We describe a solid-phase immunochromatographic serologic test, FlexSure HP, to detect IgG antibodies against Helicobacter pylori. H. pylori colonize the stomach and proximal duodenum, cause ulcer disease and mucosa-associated lymphoid tissue lymphoma, and have a role in the development of other disorders, including gastric adenocarcinoma. FlexSure HP consists of a test strip, conjugate pad, and absorbent pad, in a novel reverse-flow chromatography format. In these studies, FlexSure HP was demonstrated to be specific for IgG antibodies against H. pylori. The reactive cutoff of the test was consistent with [13C]urea breath test and commercially available ELISAs. FlexSure HP had 94% sensitivity, 88% specificity, and 91% accuracy relative to [13C]urea breath test; and 95% sensitivity, 94% specificity, and 95% overall agreement relative to high-molecular-mass cell-associated protein enzyme immunoassay (HM-CAP EIA). FlexSure HP is a simple-to-perform, visually read test requiring no specialized training, equipment, or instrumentation, and yields rapid, accurate, qualitative results.

Adrenal disorders. A primary care approach

Small in size but powerful in influence, the adrenal glands and their hormones are necessary to sustain life and maintain homeostasis. If not detected in a timely fashion, adrenal disorders can have fatal consequences. This articles reviews the anatomy and physiology of the adrenal glands and, with the use of case studies, considers many disorders of the adrenal glands, including Cushing's disease, aldosteronism, hyperaldosteronism, and Addison's disease.

Comparison of rapid serological tests (FlexSure HP and QuickVue) with conventional ELISA for detection of Helicobacter pylori infection

BACKGROUND

There is a need for accurate and rapid tests for Helicobacter pylori infection especially since the recent National Institutes of Health Consensus Development Conference on H. pylori in peptic ulcer disease charged the medical community with treating H. pylori infection in all patients with H. pylori and ulcer disease.

METHODS

We prospectively compared a simple, rapid serological test (FlexSure HP, SmithKline Diagnostics) for the detection of serum IgG antibodies against H. pylori with another rapid test (QuickVue, Quidel) and two enzyme immunoassays (HM-CAP, Enteric Products, and PyloriStat, BioWhittaker). Serum samples from 551 individuals including both symptomatic patients (196) and asymptomatic volunteers (355) were tested for the presence of IgG antibodies against H. pylori. The presence or absence of active H. pylori infections was determined using the [13C]-urea breath test.

RESULTS

All of the serological tests performed well. FlexSure HP had calculated sensitivity, specificity, and accuracy of 94.4, 87.6, and 91.1%, respectively, relative to the urea breath test. In 49 of the 551 samples, the urea breath test and FlexSure HP did not agree. Those samples were tested with HM-CAP immunoassay to confirm presence or absence of IgG antibodies against H. pylori. After the resolution of the discordant results, the sensitivity, specificity, and accuracy of FlexSure HP were 96.0, 95.1, and 95.6%, respectively, and were comparable to HM-CAP and PyloriStat. FlexSure HP was compared with histology or culture in 75 cases, and the accuracy was 100%. FlexSure HP and QuickVue were compared using 200 serum samples. FlexSure HP was more specific (88.7 vs 79.4%) and accurate (91 vs 84%) than QuickVue (p < 0.05 for both), relative to the urea breath test with discordant samples unresolved. FlexSure HP was also simpler to use, easier to interpret, and faster than QuickVue. FlexSure HP required no sample dilution, one reagent, four steps, and 5 min to complete.

CONCLUSION

FlexSure HP is an excellent option for in-office tests for the physician who desires immediate results or for small laboratories that do not have the volume of H. pylori testing to justify ELISA test formats.

Australian deliberations on access to its terrestrial and marine biodiversity

The predominantly developed country business principle that the natural resource is effectively free, or of very low monetary value, has been significantly challenged in recent years, not only through the recognition of the accelerated rate of depletion of native forest resources and of the space and food demands of increasing populations, but also through international conventions which deal with a wide range of topics from the rights of indigenous people to the Law of the Sea Convention. Australia, classified as a developed country, but located in a geographic region of many developing countries, has, in the past 25 years, demonstrated particular concern for the rights of the people of those countries, as well as for the rights of indigenous people of Australia. The practical international aspects were clearly exemplified in the time, from 1985, when the Australian Institute of Marine Science (AIMS) negotiated, within the National Cancer Institute (NCI) contract, that collections of biological samples in developing countries would be accompanied by an agreement to provide benefits arising from field work, and from any commercial product developments, to those countries. Australia, as a signatory to the Convention on Biological Diversity (Appendix I), continues to analyze the challenge presented by the need to freely exchange genetic resources of common value, e.g. food crops, while insuring an appropriate reward to developing and developed countries, should discoveries be made from their biological resources, which lead directly or indirectly, to high value commercial non-food products. The Prime Minister's Coordinating Committee on Science and Technology established a special working group to recommend on access to Australia's biodiversity. The report arising from the study, and other related issues, are discussed.

Natural product drug discovery and development: new perspectives on international collaboration

Until recently, the prevailing attitude in developed nations regarded the world's genetic resources, which are mainly concentrated in the developing world, as a common resource of humankind, to be exploited freely irrespective of national origin. With the devastation being wreaked in the tropical rainforests and the resurgence in interest in recent years in the discovery of novel drugs from natural sources, particularly plants and marine organisms, the international scientific community has realized that the conservation of these global genetic resources and the indigenous knowledge associated with their use are of primary importance if their potential is to be fully explored. With this realization has come a recognition that these goals must be achieved through collaboration with, and fair and equitable compensation of, the scientists and communities of the genetically rich source countries. The signing of the United Nations Convention on Biological Diversity by nearly all of the World's nations has emphasized the need for the implementation of such policies. In this review, the articles of the Convention of relevance to the activities and practices of the natural products scientific community are briefly discussed. This discussion is followed by a summary of policies for international collaboration and compensation being implemented by several developed country organizations, and the perspectives on the current developments given by representatives of some of the source countries located in the regions of greatest biodiversity.

Expression and processing of parathyroid hormone-related protein in a pancreatic endocrine cell tumour associated with hypercalcaemia

We describe a patient with a neuroendocrine tumour of the pancreas associated with hypercalcaemia which was attributed to production of parathyroid hormone-related protein (PTHrP) by the tumour. Plasma PTHrP 1-86 was significantly raised, and fell following surgical resection of the tumour. PTHrP mRNA and peptide were identified in tumour tissue by in-situ hybridization and immunohistochemistry respectively. PTHrP was quantitated in an extract of tumour tissue by three region-specific immunoassays (PTHrP 1-34 45.2 pmol/g, PTHrP 37-67 81.7 pmol/g, PTHrP 1-86 27.3 pmol/g) and suggested the presence of excess of amino-terminal and mid-region immunoreactivity. On chromatography of the tumour extract the first peak eluted as 22 kDa and comprised approximately equimolar 1-34, 37-67 and 1-86 activities. The second and major peak of 16 kDa contained only 37-67 activity, while the third peak of 6 kDa contained only 1-34 activity. This suggested that the tumour contained a native or intact form of PTHrP together with two major subfragments containing 37-67 and 1-34 activity respectively. Thus chromatographic separation and quantitation of PTHrP by region-specific immunoassays have provided new information on in-vivo proteolytic processing by tumour tissue by indicating that a site of cleavage is located between residues 17 and 61. Our findings are compatible with cleavage at residue 37, a site previously indicated from in-vitro studies.

Assessment of the impact of rising carbon dioxide and other potential climate changes on vegetation

The projected doubling of current levels of atmospheric carbon dioxide concentration ([CO(2)]) during the next century along with increases in other radiatively active gases have led to predictions of increases in global air temperature and shifts in precipitation patterns. Additionally, stratospheric ozone depletion may result in increased ultraviolet-B (UV-B) radiation incident at the Earth's surface in some areas. Since these changes in the Earth's atmosphere may have profound effects on vegetation, the objectives of this paper are to summarize some of the recent research on plant responses to [CO(2)], temperature and UV-B radiation. Elevated [CO(2)] increases photosynthesis and usually results in increased biomass, and seed yield. The magnitude of these increases and the specific photosynthetic response depends on the plant species, and are strongly influenced by other environmental factors including temperature, light level, and the availability of water and nutrients. While elevated [CO(2)] reduces transpiration and increases photosynthetic water-use efficiency, increasing air temperature can result in greater water use, accelerated plant developmental rate, and shortened growth duration. Experiments on UV-B radiation exposure have demonstrated a wide range of photobiological responses among plants with decreases in photosynthesis and plant growth among more sensitive species. Although a few studies have addressed the interactive effects of [CO(2)] and temperature on plants, information on the effects of UV-B radiation at elevated [CO(2)] is scarce. Since [CO(2)], temperature and UV-B radiation may increase concurrently, more research is needed to determine plant responses to the interactive effects of these environmental variables.

Value of Emergency Cardiac Enzymes: Audit in a Coronary Care Unit

Medical audit in a district general hospital coronary care unit led to the introduction of an emergency cardiac enzyme service. 91.2% of patients eligible for thrombolysis therapy received treatment following this introduction compared to 73.7% before (P=.05). No patient was treated inappropriately on the basis of a raised cardiac enzyme.

Angiography of pulmonary emboli: digital studies and balloon-occlusion cineangiography

The value of digital pulmonary arteriography and balloon-occlusion cineangiography was investigated in 118 selected patients. In one series of 40 patients, digital pulmonary arteriography correctly identified pulmonary emboli in 20 (75%) of 26 positive examinations when interpretation was confined to the first three divisions of the pulmonary artery. In a second series of 78 patients with peripheral radionuclide perfusion scan defects, 40 of whom had pulmonary emboli, adjunctive balloon-occlusion cineangiography demonstrated emboli in four patients not seen on standard selective catheter pulmonary magnification studies with cut films. These two procedures (i.e., digital pulmonary arteriography and balloon-occlusion cineangiography) are important adjuncts to radionuclide perfusion scans and selective catheter pulmonary arteriography in the evaluation of patients with pulmonary emboli.

Anatomic and prognostic implications of an early positive treadmill exercise test

Eighty men (group A) with clinical coronary artery disease underwent coronary angiography regardless of symptoms and previous therapy because they had a positive treadmill exercise test in stage I or II of the Bruce protocol. Thirty-four other men (group B) who also had an early positive treadmill test underwent coronary angiography because they had disabling angina pectoris despite medical therapy. We found left main coronary artery stenosis of 50% or greater of the vessel diameter in 28% of group A and 35% of group B (p greater than 0.3). In contrast, only 10% of 93 other catheterized patients who had treadmill tests that were not early positive had left main coronary disease (p less than 0.001). Fifty-four patients from group A who did not have left main stenosis of 50% or greater were treated medically. In this subgroup, 85% had 2 or 3 major coronary vessels with 75% or greater stenosis. These patients had a 36 month survival rate of 89.2%. We conclude that an early positive treadmill test identifies patients who have an increased likelihood of having left main coronary stenosis, even if they are minimally symptomatic. To identify left main coronary stenosis, catheterization may be justified in patients whose angina pectoris has been mild or not intensively treated when they have an early positive treadmill response. After left main coronary stenosis has been excluded, these patients may be treated medically with a low mortality.

Myocardial infarct extension: incidence and relationship to survival

Myocardial infarct extension, defined as reelevation or reappearance of creatine phosphokinase-MB (CK-MB) 48 hours after the onset of symptoms, was evaluated prospectively in 56 consecutive patients with acute myocardial infarction. Myocardial infarct extension occurred in eight patients (14%). The sensitivity, specificity and predictive accuracy in the diagnosis of myocardial infarct extension were 63%, 85% and 42%, respectively, for recurrent chest pain requiring morphine; 50%, 65% and 19% for recurrent ST-segment elevation on routine 12-lead ECGs; and 88%, 63% and 28% for reelevation of total CK. Three of the eight episodes of extension were clinically silent. Four of eight patients (50%) with extension died, compared with one of 46 patients (2%) without extension (p = 0.0009). CK-MB persisted for 72 hours or longer in 16 patients and identified seven of eight patients who subsequently had infarct extension. We conclude that myocardial infarct extension is an infrequent complication of acute myocardial infarction and is associated with a very high mortality rate. Persistence of CK-MB for 72 hours or more identifies a subgroup of patients at high risk for subsequent infarct extension and death.

Pirmenol, a new antiarrhythmic agent: initial study of efficacy, safety and pharmacokinetics

Pirmenol (CI-845), a new antiarrhythmic drug, was studied for the first time in humans to establish a minimum effective i.v. dose in 10 patients with chronic, stable premature ventricular complexes (PVCs) and to evaluate toxicity and pharmacokinetics. Infusions of 70-150 mg were associated with a 90% or greater reduction in PVCs nine of the 12 times they were administered to six patients. Peak plasma concentrations were 1.0-3.8 micrograms/ml at the end of these infusions. At the same time, small but significant increases in diastolic blood pressure (4 mm Hg) and QTc interval (0.01 second) were seen, but both values were within the normal range. Pirmenol was associated with no change in heart rate, systolic blood pressure, PR interval or QRS duration, renal, hepatic or hematologic function, or symptoms. Blood, plasma and free drug concentrations declined biexponentially after cessation of a 150-mg infusion (n = 4), with a terminal half-life of 7-9.4 hours. The therapeutic response, lack of toxicity, and relatively long half-life indicate that pirmenol is a promising antiarrhythmic agent.

Development of the intrarenal vascular system of the puppy kidney

This study investigates the development of the vascular system of the puppy kidney (1-21 days after birth) after preparing casts of the renal vessels. At two days, the intrarenal vascular system distal to the afferent arteriole is strikingly different than that of the adult. The glomeruli of the outer cortex consist of a single dilated vessel while those of the mid and inner cortex posses an increasingly larger number of capillary loops. The efferent arterioles vary greatly in appearance from outer to inner cortex. Those in the nephrogenic zone are characteristically short and narrow and join a larger venous vessel termined a sinusoidal capillary. An efferent system somewhat similar to that of the adult is seen in the mid and inner cortex. One of the most obvious differences noted between the puppy and adult kidney is the relative lack of peritubular capillary networks throughout the cortex of the puppy kidney. The puppy possesses large, irregular vessels termed sinusoidal capillaries. The most rudimentary sinusoids are found in the outer cortex with more mature vessels in the inner cortex. The vascular arrangement of the efferent arteriole and sinusoidal capillary appears as a post-glomerular shunt. Functionally, the shunt would direct blood flow away from the proximal tubule and thus could result in a low extraction ratio and Tm for secreted solutes.

Dependence of p-aminohippurate transport on calcium in canine renal cortical slices

1. Experiments were conducted on renal cortical slices from sixty-one adult mongrel dogs in order to evaluate the relationship between p-aminohippurate (PAH) transport and calcium. Tissues were found to be viable for at least 180 min.2. PAH uptake and the slice/medium (S/M) concentration ratio increased in normal tissues from 3 to 90 min whether data were expressed on a tissue weight or protein content basis. PAH uptake increased with time in calcium-depleted tissues, but all values were lower than normal. At 90 min, PAH S/M in calcium-depleted tissues (4.20 +/- 0.18) was reduced 40% compared to normal tissues (6.90 +/- 0.23).3. Over the time period of 3-90 min incubation, protein concentration ranged from 89.4 to 99.4 mg/g cortex in calcium-depleted tissues. During the same time period in normal tissues, protein concentration ranged from 105 to 117.6 mg/g cortex. No change was observed in medium protein concentration of calcium-depleted tissues.4. Lineweaver-Burke analysis showed similar values for K(m) in normal and calcium-depleted tissues (0.45-0.50 mumole ml.(-1)) although V(max) fell from control values of 0.082 to 0.052 mumole g(-1) min(-1) during calcium depletion.5. After 90 min incubation, addition of EGTA (7, 14 or 21 x 10(-3)M) to media containing calcium was associated with decreased S/M and uptake rates compared to control values from the same animals. The decreases observed were similar to those seen in tissues incubated in calcium-free media.6. Increased cell volume in the presence of calcium was not associated with decreased PAH uptake. Removal of calcium in association with constant cell volume was associated with reduced PAH uptake. Replacement of calcium, but not magnesium, is associated with a return of uptake to normal rates.7. It is concluded that (a) calcium removal causes increased water uptake into cells, (b) calcium removal causes a reduced V(max), (c) calcium is required for maintenance of intracellular PAH, (d) the effect of calcium on PAH is specific and reversible, and (e) the effect of calcium is not mediated by volume changes.

Renal response to infusion of isotonic Ringer-Locke solution: effect of hypophysectomy

A comparison of the renal response to extracellular fluid volume expansion (5% body weight) was made between 25 normal and 25 chronically hypophysectomized rats. The extracellular fluid compartments averaged 25 ± 1% of body weight in both groups during control, fasted conditions. Extracellular fluid volume increased to 33 ± 1% in hypophysectomized and 34 ± 2% in normal rats during expansion, based on body weight. In addition, filtration fraction was similar in both normal and hypophysectomized rats during control (0·29 ± 0·03 and 0·26 ± 0·02 respectively) and infusion of Ringer–Locke solution (0·24 ± 0·05 and 0·27 ± 0·05 respectively). Thus our results cannot be explained by differences in the degree of expansion or failure to increase filtration in proportion to plasma flow. During infusion of isotonic Ringer–Locke solution, fractional water and sodium excretion both averaged 5·1% in normal rats and only 1·3% and 0·82% respectively in hypophysectomized rats. The ratio of single nephron to whole kidney filtration rate failed to increase as much in hypophysectomized compared with normal rats. Significant increases of fractional volume excretion occurred in both groups by the end of the accessible portion of the proximal tubule. However, fractional water reabsorption was depressed significantly more in normal (mean = 37%) than in hypophysectomized rats (mean = 19%). Fractional water reabsorption in distal tubules was similar in both groups during expansion. Arterial pressure was lower in hypophysectomized rats under control conditions, but showed similar changes during expansion compared with normal rats. Passage time decreased significantly in all groups after Ringer–Locke infusion, but remained prolonged in hypophysectomized rats in proximal and distal tubules. It is concluded that chronic hypophysectomy results in a less efficient renal excretion of volume and sodium chloride load. This inefficiency appears to be related in part to (1) failure of the proximal tubule to depress water reabsorption to a level equivalent to normal rats, and (2) failure to re-distribute flow to outer cortical glomeruli following extracellular fluid volume expansion in hypophysectomized rats.

Extraction fraction at any urine flow and extraction percentage

Extraction fraction of renal solutes is ordinarily calculated as a ratio of arterial and venous concentration differences. Calculations provided in the present manuscript illustrate the need to correct for changes in renal venous concentration when solute extraction is low and urine flow simultaneously high.

Synthesis of new 14-, 15- and 16-membered crown compounds containing oxygen and nitrogen heteroatoms

Facile syntheses for new 14-, 15-, and 16-membered crown compounds derived from salicylaldehyde and 5-chlorosalicylaldehyde are reported. The new compounds contain both oxygen and nitrogen heteroatoms.

Zonulae occludentes of the rat nephron under conditions of experimental expansion of blood and/or fluid volume

The zonula occludens (Z.O.) has been implicated as a major pathway for passive fluid movement from lateral intercellular spaces to lumen in response to an expansion of blood or fluid volume. The present study examines to Z.O. of adult rat nephrons in control and Ringer-Locke or while blood infused animals to determine whether varying the conditions of passive fluid movement would influence the structure of the Z.O. Rats were infused over 20 minutes with Ringer-Locke (7% body weight) or while blood (2.3% body weight). In the controls, 92%-94% of all Z.O. observed in proximal tubules and 100% of Z.O. from distal tubules and collecting ducts had fused outer leaflets. The approximate linear extent of the Z.O. was 140 A for proximal tubules, 2,500 A for distal tubules and 3,000 A for collecting ducts. There was no significant difference in any of these values following the infusion with either Ringer-Locke or whole blood. We conclude that expansion of blood or fluid volume causes no detectable alteration in the fine structure of Z.O. under the conditions used in the present study.

Maturation of the renal response to hypertonic sodium chloride loading in rats: micropuncture and clearance studies

1. The ability of maturing rats to excrete a sodium load was studied by micropuncture and clearance procedures. 2. During control conditions, no change of glomerular filtration rate or sodium excretion was observed for the time period of the entire procedure (P greater than 0-20). During the infusion of hypertonic (4%) sodium chloride, fractional sodium excretion was 0-08 +/- 0-01 in rats 21-30 days old and 0-14 +/- 0-01 (P less than 0-01) in adults. However, the depression of proximal tubular water re-absorption was equal in both groups (P greater than 0-20). 3. Proximal glomerulotubular balance for water re-absorption was similar in all groups (P less than 0-20). Since end proximal tubular water excretion and depression of fractional water excretion were the same in all animals, differences of urinary sodium excretion during development are probably due to differences of function of segments beyond the proximal tubule during development. 4. Fractional potassium excretion was reduced in young rats (0-17 +/- 0-04) during hypertonic sodium chloride infusion, compared to adults (0-24 +/- 0-01, P less than 0-05). 5. Passage time of fast green through cortical segments in seconds is prolonged in young rats during control conditions. Similar decreases of passage time were seen in all groups during hypertonic sodium chloride infusion. No segmental differences of passage time were seen during developmental. 6. No difference in the relationship between fractional sodium and water excretion was seen during development of the renal response to hypertonic sodium chloride infusion. Thus, altered sensitivity to sodium chloride osmotic diuresis does not exist during maturation in rats.

The chemistry of the indoleninones. III. Reactions of 2-(Methylthio)indoleninones with diazomethane

The reactions of 2-(methy1thio)indoleninone [2-(methylthio)-3H-indol-3-one] and its 4-bromo and 6-bromo derivatives with diazomethane lead to the appropriate 2-(methylthio)spiro[3H-indole-3,2'- oxirans] and 3-methoxy-2-(methy1thio)quinolines in relative yields dependent upon the steric in- fluence of bromine when in the 4-position. P.m.r. studies on the 2-(methylthio)spiro[3H-indole-3,2'-oxirans] reveal a marked solvent depen- dence on the chemical shift values of the non-equivalent protons of the methylene group in the oxiran ring.

Relationship between glucose and sodium excretion in the new-born dog

1. The relationship between renal glucose and sodium excretion was studied in thirty-three new-born dogs aged 1-14 days and in ten adult dogs.2. Glucose was infused into the animals at rates sufficient to produce an amount of filtered glucose at least 1.5 times the tubular transport of glucose (saturating glucose load). In both puppies and adults tubular glucose reabsorption at saturating glucose loads varied directly with the glomerular filtration rate (r = 0.54 and 0.73 respectively, P < 0.01 for both).3. In the puppy, as the fraction of filtered sodium excreted (C(Na)/C(In)) increased from 0.05 to 0.45, the ratio, renal tubular glucose transport divided by glomerular filtration rate at saturating glucose loads, (T(G)/GFR)(m), decreased from 3.7 to 1.7 mg/ml. (r = -0.75, P < 0.01). In the adult C(Na)/C(In) was below 0.08 in all experiments and (T(G)/GFR)(m) was within the 95% confidence limits predicted by regression analysis of the data from puppies. Although mean (T(G)/GFR)(m) was greater in the adult than in the puppy (P < 0.01), when puppies had C(Na)/C(In) similar to that for adults, they had (T(G)/GFR)(m) values equivalent to that for the adult.4. There was excellent correlation between glucose excretion and water excretion for both adult and new-born dogs (r = 0.93 and 0.87, respectively). However, for any glucose loss, water loss was greater in the puppy than in the adult (P < 0.01).5. During the control period total sodium excretion (per gram kidney) and C(Na)/C(In) were similar in the new-born and adult dog. However, during glucose loading, the puppies excreted more sodium and had a higher C(Na)/C(In) than did the adult, although glucose excretion was greater in the adult than in the puppy (P < 0.01 for all comparisons).6. Glomerular blood flow, as measured by radioactive microspheres, was redistributed towards inner cortical nephrons during glucose loading in the puppy. There was no such redistribution of glomerular blood flow in the adult.7. Sodium reabsorption beyond the proximal tubule was blocked with ethacrynic acid and chlorothiazide. In the puppy, the increase of C(Na)/C(In) following a glucose load was the same whether the glucose load followed control or distal blockade collections, suggesting that reductions of sodium reabsorption following a glucose load probably came from the proximal tubule. C(Na)/C(In) during glucose loading plus distal blockade was significantly (P < 0.01) higher in the puppy (0.598) than in the adult (0.280), indicating that glucose diuresis produced a greater inhibition of proximal tubular sodium reabsorption in the new-born than in the adult dog. These results support the hypothesis that the high sodium excretion rate during glucose diuresis in the new-born dogs appears to be due to the greater sensitivity of the neonatal proximal tubule to the osmotic effect of glucose. When presented with a glucose osmotic load the new-born dog diminishes net proximal sodium reabsorption more than does the adult and thus depresses tubular glucose reabsorption to a greater extent. The lower values of maximal glucose transport rates found in new-born animals may be related, therefore, to the higher fractional sodium excretion rates during glucose diuresis rather than to a diminished intrinsic glucose transport capacity in the new-born kidney.

Jaundice following open-heart surgery

Singh, H. M., and Baker, J. T. (1974). Thorax, 29, 68-74. Jaundice following open-heart surgery. A study was made into the factors influencing the onset of jaundice in 102 patients undergoing valve replacement during cardiopulmonary bypass. Postoperative jaundice appeared to be correlated with double valve replacement, the co-existence of an uncorrected valvular lesion, length of perfusion and myocardial ischaemia times, and also the age of the patient. Factors appearing not to be correlated with the onset of jaundice included preoperative pulmonary artery pressure, cardiac index, parameters of preoperative renal and hepatic function, and the amount of blood used during bypass. The biochemical features of the jaundice seemed to follow a pattern not previously recognized in this context, with sometimes considerably raised bilirubin levels in association with virtually normal levels of transaminases and alkaline phosphatase.

Chemistry of the indoleninones. II. Isolation from the hypobranchial glands of marine molluscs of 6-Bromo-2,2-dimethylthioindolin-3-one and 6-\Bromo-2-methylthioindoleninone as alternative precursors to Tyrian purple

6-Bromo-2-methylthioindoleninone and 6-bromo-2,2-dimethylthioindolin-3- one have been isolated from ether extracts of Dicathais orbita Gmelin. Both compounds are derived from the absolute precursor sodium tyrindoxyl sulphate. ��� Isolation of the compounds from certain other species of molluscs is reported.

The volatile constituents of the scent gland reservoir of the fruit-spotting bug, Amblypelta nitida

Using combined gas chromatography and mass spectrometry, ten components of the scent-gland complex of the coreoid Amblypelta nitida Stal have been identified. Of specific interest is the presence in the gland reservoir of 2-n-butyloct-2-enal, the aldol condensation-dehydration product of hexanal.

Chemistry of the indoleninones. I. Derivatives of 2-chloroindoleninone (α-chloroisatin) on reaction with methanethiol, benzenethiol, and 1,2-ethanedithiol

The reactive 2-chloroindoleninone has been used to prepare a series of 2,2-and 3,3-dialkylthio- and diarylthio-indolinones, 2-phenylthioindoleninone, and 2-methylthioindoleninone, the last named being a debromo analogue of a product of hydrolysis and dehydrogenation of 6-bromo-2-methylthioindoxyl sulphate, an absolute precursor to the major constituent of the dye Tyrian Purple.

Bowel habit in thyrotoxicosis and hypothyroidism

A prospective study of bowel frequency in patients with thyroid disease showed increased frequency of bowel action in thyrotoxicosis and decreased frequency in myxoedema. The contrary findings of previous studies may be due to the use of inexact criteria in interrogation of the patients.