Vitamin E--its significance in mouse ageing

A small colony of C3H/He and LAF1 mice was set up with 50% of all stock being given a dietary supplement of 0.25% w/w vitamin E to study the range of ageing variables over which anti-oxidant administration has an effect. An increase in mean but not maximum lifespan with vitamin E was attributable to fewer fatalities early in life. This may have been due to low anti-oxidant levels in the controls. Lower fatal tumour incidence in both strains and a decrease in collagen content of LAF mice were noted. Lipofuscin levels in heart tissue were, as expected, reduced but the significance of lipid peroxidation to ageing of the organism is questioned.

Tissue core biopsy of abdominal tumors with a 22 gauge cutting needle

Percutaneous needle sampling of malignant tumors carried out by fine-needle cytologic aspiration and large-needle cutting techniques both possess certain limitations. A fine caliber 22 gauge cutting needle and a modified sampling technique used in 78 patients with suspected abdominal neoplasms are described. Both cytologic and histologic samples were sought in each case and overall successful diagnoses were made in 88% of 50 proved cases, with specific histologic diagnoses in 56%. Cytologic specimens were more sensitive in 14 cases in the detection of malignancy, while histologic results were more specific in nine cases. No significant complications were encountered. This modified method has not replaced the former cytologic aspiration technique in this institution.

Changes in skinfold thickness with increasing age

Skinfold thickness measurements on 626 normal subjects of both sexes between the ages of 5 months and 73 years demonstrated a tri-phasic relationship between loss of skin thickness and age. Measurements for infants of either sex were indistinguishable and high, falling rapidly to levels which only changed slightly over the period 20-60 years. Thereafter, massive loss of skin-thickness occurred in both sexes. Throughout the major portion of adult life the values obtained for females were significantly lower than those for males. It is suggested that the three phases may be associated with progressive dehydration, failure to synthesize collagen and frank degradation of the collagen of the dermis.

The effects of vitamin E on mouse fitness and survival

A small colony of C3H/He and LAF1 mice, of which 50% were receiving a diet supplemented with vitamin E (0.25%, w/w, dl-alpha-tocopherol), was set up for investigation of the reported action of antioxidants on increasing longevity. It was found that vitamin E exerted no effect on maximum longevity, but increased the numbers of both genotypes surviving to 24 months. The beneficial effects appeared to act by reducing the incidence of fatal tumours late in life and by counteracting a debilitating condition early in life. It is suggested that this debility may have resulted from low antioxidant in the control diet. The relevance of free radicals to ageing is questioned.

Temperature effect on ADH response of isolated perfused rabbit collecting tubules

The time course of the water permeability response to synthetic arginine vasopressin (AVP) was examined in isolated perfused rabbit collecting tubules. When experiments were conducted at 37 degrees C, addition of AVP in a concentration of 100 microU/ml increased hydraulic water permeability (Lp) from 18 +/- 4 X 10(-7) to 153 +/- 15 X 10(-7) cm x s-1 x atm-1. However, in contrast to results obtained at 25 degrees C, the Lp immediately decreased in spite of the continued presence of AVP, reaching half the peak value in 67 +/- 6 (SE) min. A similar decline was observed at 37 degrees C when a cyclic 3',5'-adenosine monophosphate analogue was added to the bathing medium. Corticosteroids greatly enhanced the peak water absorption but did not stabilize the subsequent response to AVP at 37 degrees C. A decline in diffusional water permeability measured in the absence of a transtubule osmotic gradient excluded the possible roles of cellular hypotonicity, increased cell volume, or osmotic water absorption in the unstable response to hormone. The peritubular membrane remained highly permeable to water, independent of AVP and temperature. Duration of exposure to 37 degrees C was more important than AVP in determining the unstable response. On the basis of these studies we conclude that isolated rabbit cortical collecting tubules progressively become insensitive to AVP at 37 degrees C, possibly due to alterations in the responsiveness of the urinary plasma membrane to cAMP.

The action of vitamin E on the ageing of connective tissues in the mouse

In an attempt to determine the relevance of the free radical theory of ageing to age changes discernible in connective tissue parameters, a small colony of C3H/He and LAF1 mice was set up, with sample culled at intervals throughout the lifespan to provide experimental samples. To half of the stock a dietary supplement of vitamin E, a naturally occurring antioxidant, was given at a level of 2500 mg/kg of diet. Tests were carried out on culled samples to provide data on the total collagen levels of bone and skin, on thermal shrinkage temperature and maximal degree of shrinkage of tendon fibres, and on the recovery of skin from stress. Vitamin E was found to have no effect on any of the parameters measured on C3H/He mice but to exert an influence on the parameters of LAF1 mice around the age of 10 months. This influence, however, is not regarded as being relevant to the ageing of the tissues and thus no evidence can be derived for a free-radical mechanism playing a role in the ageing of connective tissues.

Related age changes in the elastase and lipid contents of normal and hemiplegic subjects of various ages

Elastase and lipid levels of the plasmas of subjects and of those who have suffered a stroke have been measured, and it has been shown that the normal age related fall in elastase content is mirrored more closely by the fall in high density lipoprotein cholesterol than by changes in total cholesterol. After a stroke a peak level of the elastase concentration is reached later than the peak of the total cholesterol, but before the peak for the HDL-cholesterol is attained. Highest levels of the ratio of these two (a major risk factor in vascular disease) appear to precede both the stroke and the elevation of the elastase level at ages below 76 whereas at higher ages than this the elevation of elastase precedes the lipid changes. It is therefore deduced that the whole question of elastolytic activity in the plasma is intimately bound up with the lipid content of the plasma and with the age of the subject as mirrored in the status of the elastic tissue in the vessel wall.

Effect of vasopressin on electrical potential difference and chloride transport in mouse medullary thick ascending limb of Henle's loop

Medullary thick ascending limbs of Henle's loop of the Swiss-Webster mouse were perfused in vitro with an isotonic perfusate and a Ringer's bathing medium. In five studies, addition of a supramaximal concentration of synthetic arginine vasopressin (AVP) to the bathing medium resulted in an increase in electrical potential difference (PD) from 5.0 +/- 1.5 mV, lumen positive, to 10.7 +/- 1.4 mV (P < 0.001). When AVP was removed, the PD returned to 2.6 +/- 0.9 mV (P < 0.001), then increased again to 6.9 +/- 1.7 mV (P < 0.01) when AVP was added a second time. A significant, but submaximal, increase in PD of 2.3 +/- 0.6 MV (P < 0.05) was observed in five medullary thick ascending limbs when AVP was added to the bathing medium at a concentration of 10 microunits/ml. This increase was approximately one-third of the response observed at a concentration of 100 microunits/ml in the same tubule. No further increment in PD was observed in five medullary thick ascending limbs when the AVP concentration was increased from 100 to 1,000 microunits/ml. In seven thick ascendcing limbs, the effect of AVP on PD was reproduced by the addition of 8-[p-chlorophenylthio]-cyclic 3',5'-adenosine monophosphate to the bathing medium at a final concentration of 0.1 mM. AVP increased unidirectional chloride flux from lumen to bath from 29.3 +/- 3.2 to 69.8 +/- 6.2 peq/cm per s (P < 0.001) in spite of an increase in the lumen positive PD from 1.6 +/- 0.5 mV to 7.0 +/- 0.6 mV (P < 0.001). Unidirectional chloride flux from bath to lumen was not affected by AVP. In another series of experiments, net chloride flux increased from 15.6 +/- 3.0 to 41.7 +/- 5.3 peq/cm per s (P < 0.05) after addition of AVP. The effect of AVP on hydraulic water permeability (Lp) was examined by adding raffinose to the bathing medium in both the presence and the absence of AVP. The calculated Lp of 16 +/- 2 nm/s per atm in the absence of AVP, although very low, was significantly different from zero (P < 0.01). However, the Lp did not increase significantly when AVP was added to the bathing medium. These results suggest that AVP has a second site of action in the kidney to increase chloride transport by the medullary thick ascending limb in addition to its well-known effect on the water permeability of the collecting tubule. The former effect would contribute to urinary concentrating ability by increasing the axial osmotic gradient in the renal medulla.

Serum elastase levels following a stroke in elderly subjects

The elastase content of the serum of stroke patients is appreciably higher immediately after the cerebral incident and, in the case of those destined to survive, falls subsequently back to the normal level for their age group. The degree of elevation of the elastase content, the period which elapses before it is attained and the rate at which the level returns to normal are all age related. Those patients who die within 1 week of their initial stroke suffer a dramatic rise in serum elastase content immediately prior to death.

Sonographic morphology of the normal menstrual cycle

Sequential gray-scale sonograms were obtained during 20 menstrual cycles in 16 normal female volunteers. Hormonal and physical parameters of an ovulatory cycle were correlated with morphological changes in the ovaries, uterus, and cul-de-sac as seen on the sonogram. Ovarian cysts of two sizes were observed, corresponding chronologically and morphologically to Graafian follicles and corpora lutea. Small amounts of free pelvic fluid were demonstrated in many women at ovulation. A characteristic uterine appearance is seen prior to menstruation and is related to hormonal influences on the uterus. These findings emphasize the importance of recognizing normal physiological changes when interpreting gynecologic sonograms.

Mittelschmerz. Sonographic demonstration

Ultrasonography of the pelvis at mid-menstrual cycle in normal women has demonstrated small quantities of free fluid in 40% of cycles. Two thirds of the cycles associated with pain had ultrasonically demonstrated fluid at ovulation. These sonographic findings at Mittelschmerz confirm the physiological trauma of ovulation.

Computed body tomography in chronic pancreatitis

CT of the pancrease permitted correct positive diagnosis in 28/50 or 56% of patients with chronic pancreatitis proved by laparotomy or retrograde ductography. Diagnoses were based on CT identification of one or more specific hallmarks of chronic pancreatitis including calcifications (18/50 or 36%), parenchymal atrophy (7/50 or 14%) and pancreatic duct dilatation (2/50 or 4%), as well as the principal surgical complications, pseudocyst and abscess (15/50 or 30%). In 9 patients, CT disclosed pancreatic calcifications not visible on conventional radiographs. In 32 patients, ultrasound was less informative than CT giving a correct diagnosis in 8 pseudocycts (25%). In the patient with unexplained upper abdominal complaints, a positive CT diagnosis of chronic pancreatitis permits more confident patient management than a negative, or "no tumor" diagnosis rendered by other noninvasive examinations.

Scanning techniques in computed body tomography

Clinical examinations with the whole body CT scanner require considerable individualization of examination technique in relation to specific organs, anatomic areas, and clinical problems. Careful selection of radiographic factors, patient position, contrast agents, and pharmacologic adjuncts will optimize diagnostic results and patient throughput.

Sleep, mood, and fatigue during a 14-day He-O2 open-sea saturation dive to 850 fsw with excursions to 950 fsw

To obtain information on sleep, mood, and performance of divers and surface support personnel during deep dives in the open sea, 12 divers and 12 surface support personnel were monitored during a 14-day open-sea saturation dive using the U.S. Navy Deep Diving System, Mark 2, Mod O. Divers lived in the deck decompression chambers at 850 fsw equivalent and made 5 days of excursion wet dives to approximately 950 fsw via the Personnel Transfer Capsule. Electroencephalographic and self-report measures of sleep, and measures of mood, anxiety, and 4-choice reaction time performance were obtained during a predive base-line period and throughout the dive and decompression. Results suggested that, unless personnel are rotated, there are limitations to the practical duration of very deep open-sea saturation dives caused by the accumulation of sleep debt, fatigue, and loss of psychological vigor.

Clinical application of a single compartment model to urea and creatinine kinetics in dialysis therapy

A single compartment mathematical model has been shown to accurately described changing serum concentrations of low molecular weight solutes (urea and creatinine) during dialysis. Clinical application of the model permits prediction of serum concentrations in response to changes in prescription of dialysis therapy. The programs presented here can be used to predict the effect of changes in treatment time and dialyzer clearance on serum concentrations. Sequential pre- and end-dialysis solute concentrations are displayed on a programmable pocket calculator. Dialyzer clearance during any individual dialysis can be calculated. These programs permit an evaluation of the efficacy of prescribed dialysis treatment schedules in advance of therapeutic trials.

The breast as a mirror of systemic diseases

This paper reemphasizes that xeromammographic changes in the skin, parenchyma, and vascular structures of the breast may be manifestations of a host of systemic diseases. Xeromammographic examples of such diseases as congestive heart failure, diabetes mellitus, collagen vascular diseases, and endocrine diseases are presented and discussed.

Extension of pulmonary O2 tolerance in man at 2 ATA by intermittent O2 exposure

To study extension of O2 tolerance by interruption of hyperoxic exposure, as compared to previous studies of continuous oxygen exposure, five healthy volunteers were exposed to oxygen at 2 ATA on an intermittent schedule of 20 min breathing O2, alternating with 5 min on a normoxic N2-O2 mixture. The cycle was repeated until symptoms or signs of O2 toxicity caused cessation of the experiment. Tracheal irritation and burning on inspiration occurred after 6-9 "oxygen hours" of exposure and progressed to severe tracheobronchial burning sensation, chest pain, and dyspnea after 11-15 h of O2. Average duration of exposure was 13.7 O2 h, inducing a mean vital capacity decrease of 10.3%. The decrease began soon after onset of symptoms. With intermittent O2 administration, nearly a doubling of the average duration of actual oxygen breathing was required to induce marked vital capacity change (greater than 10%) as compared to the previous studies of continuous O2 exposure. The increased duration of tolerable O2 exposure in man resembles the extension of O2 tolerance known to occur in animals exposed to intermittent hyperoxia.

Cyclic AMP in action of antidiuretic hormone: effects of exogenous cyclic AMP and its new analogue

Exogenous cyclic 3',5'-adenosine monophosphate (cAMP) stimulates the effect of the antidiuretic hormone, vasopressin (VP), only in pharmacologic quantities and results have often been inconsistent. The present study examined the ability of a new analogue, 8-[p-Cl-phenylthio]cyclic 3',5'-adenosine monophosphate (C1-PheS-cAMP) to mimic the effect of VP, both biochemically (protein kinase activation) and functionally (hydrosomatic response of perfused collecting tubules) in mammalian kidney tissue. C1PheS-cAMP was found to be about 100 times as effective as cAMP both biochemically and functionally. The increased effectiveness of C1PheS-cAMP is probably is probably due to a greater permeability across the cell membrane and to the resistance of C1PheS-cAMP to enzymatic degradation, Cyclic AMP phosphodiesterase inhibition was observed with C1PheS-cAMP, but its contribution to overall effect was minor. C1PheS-cAMP was found to be more effective than exogenous vasopressin, an effect probably due primarily to its resistance to catabolism. The results provide further new evidence that cAMP and protein kinase are involved in the cellular action of vasopressin. C1PheS-cAMP proved to be a useful tool in the study of hormone action, especially in steps subsequent to cAMP generation.

Gas phase separation during decompression in man: ultrasound monitoring

During two dive series, one to 132 fsw and one to 210 fsw, Doppler ultrasonic bubble detectors were used to monitor venous gas bubbles in divers during decompression and for 30 min thereafter. Various decompression schedules were used. Bubble scores were evaluated by independent listerners to tape recordings in a blind manner. A significant increase in bubble scores throughout the stages of decompression and postdecompression was demonstrated as well as a statistically significant relationship between bubble score and decompression sickness. A reduction in mean bubble score was found in divers who made an additional deep decompression stop that was unrelated to the extension of the decompression time. The implications of these findings are discussed.

Associations between psychological factors and pulmonary toxicity during intermittent oxygen breathing at 2 ATA

Associations between the psychological and pulmonary effects of breathing intermittent oxygen at 2 ATA were examined among four experienced divers. A fifth diver, who served as a control, breathed only normoxic nitrogen. Psychological tests included digit span, short-term memory for easy and difficult word associations, simple and complex psychomotor performance, and reported moods. The criterion of oxygen toxicity was the total hours of intermittent oxygen exposure tolerated before developing a 10% reduction in vital capacity. Short-term memory for difficult word associations and self-reported moods of Activity, Depression, Fatigue, and Happiness were found to be significantly correlated with this criterion of oxygen toxicity. Part of the impairment found on these measures, however, was probably related to the absence of adequate sleep and rest as evidenced by the worsened performance of the control diver over the 15-h testing period. The results replicated the findings of earlier research on the psychological effects of continuous oxygen breathing under hyperbaric conditions and at 1 ATA, and may indicate that oxygen intesifies the effects of other stressors such as fatigue. In addition, the results showed that reported moods may be important indicators of impending pulmonary toxicity during intermittent oxygen exposure.

The physical properties of elastic fibers and elastolysis

The effects of two forms of elastase on the Young's Modulus of elastic tissue have been studied. The monomeric, calcium poor form of the enzyme lowers the value of the Young's Modulus before an appreciable amount of protein is taken into solution. The polymeric, calcium rich enzyme on the other hand degrades the protein before reduction in Young's Modulus occurs. On the basis of these observations, it is confirmed that the enzyme/substrate complex in elastolysis is formed by interaction through a co-ordinately bound calcium atom and that this atom can be derived either from the substrate, where it stabilises the molecule, or from the enzyme.

Application of a programmable pocket calculator to a single compartment mathematical model of solute kinetics

A single compartment mathematical model has been applied to kinetics of small solutes (urea and creatinine) in dialysis therapy. The model can be described by two equations requiring iterative solution of calculated values, given several measurable variables. The equations have been programmed onto a Hewlett-Packard 65 pocket calculator and recorded on 3 X 1/2" magnetic strips, facilitating clinical application to dialysis therapy.