Elderly patients and their medication: a post-discharge follow-up study

Fifty-six elderly patients (age range 65-98 years) discharged from a geriatric unit were visited at home on or after the 5th post-discharge day (median day 8) and their medication assessed. By the day of the visit, 15 of the 56 had not had a new prescription issued (27%) and 27 patients (48%) had old prescribed medication at home. Forty-one new scripts, issued by general practitioners, should have contained 128 medications if the general practitioners wished to continue unchanged the medication given on hospital discharge. Fourteen drugs (11%) had been added and 17 drugs (13%) omitted. The number of prescriptions issued unchanged was 26/41 (63%). Inaccurately labelled containers and/or changed drug names were found in 28%. Contrary to hospital advice, 47% of medications were issued in childproof containers. Poor communication between hospital and general practitioners is only part of the problem. Methods to expedite the delivery of new prescriptions should be developed.

Comparison of inorganic elements from autopsy tissue of young and elderly subjects

Concentrations of nine inorganic elements in autopsy samples of kidney, liver, heart and skeletal muscle from 33 aged subjects, mean age 80 years, were compared with concentrations in similar samples from 12 young healthy accident victims, mean age 29 years. Tissue samples were removed within 48 hours of death and dry weight was used as a frame of reference. Potassium and magnesium were significantly lower in muscle (P less than 0.001) and heart tissue (P less than 0.001) of elderly subjects. There was evidence of accumulation of zinc in liver tissue of the elderly (P less than 0.01). Copper was significantly lower in the heart tissue of elderly subjects (P less than 0.001) whereas manganese was lower in both the heart (P less than 0.01) and the kidney tissue (P less than 0.001) of the elderly. Selenium concentrations were lower in the kidney (P less than 0.001) of the elderly. Elderly heart tissue appeared to accumulate chromium (P = 0.007) and aluminium (P less than 0.001). No significant differences were found for iron concentrations between these two populations. These major differences in tissue element concentrations between young and aged subjects merit further attention.

Light and scanning electron microscopic changes observed in experimental arterial forks of rabbits

Experimental arterial forks were fashioned by anastomosing one common carotid artery to the contralateral vessel by microvascular surgery in rabbits. In one rabbit group the forks were examined histologically by the serial section technique from 5.5 to 25 months postoperatively. The second group was used for scanning electron microscopy of the arterial endothelial surface from 1 to 257 days post-operatively. Intimal proliferation was observed at the lateral angles histologically at sites comparable to those where intimal proliferation occurs spontaneously in human infants. In addition, disruption of the internal elastic lamina with minimal intimal proliferation occurred at the sides of the neo-apex, mostly in the transposed artery. These disruptions corresponded to predominantly transversely orientated tears of the internal elastic lamina from 8 days post-operatively in the scanning electron microscopic study. They were similar to the early atrophic changes preceding berry aneurysm formation in human cerebral arterial forks. The results indicate that both intimal pads (cushions) and elastic tears can be haemodynamically induced.

Rapid orocecal transit in chronically active persons with high energy intake

Although chronic physical activity by humans can raise energy requirements and energy intake severalfold above sedentary levels, whether these increases alter digestive strategy remains unknown. To investigate this possibility, food passage rate (mouth-to-large intestinal lactulose transit) and absorption (xylose) were compared in a cross section of young men chosen to represent a wide range of daily physical activity and food intake. In 20 men (energy intake 1,272-5,342 kcal/day), resting mouth-to-cecum transit was faster in high caloric consumers (r = -0.69, P less than 0.01). In contrast, xylose absorption (n = 26; measured either as urinary xylose excretion or integrated breath H2 production from the sugar) was unrelated to food intake. Dietary fiber intake was uncorrelated with energy intake. This apparent human digestive strategy of rapid transit across the gut absorptive surface, without a sacrifice in absorption, parallels the adaptations made by several animal species similarly faced with increased energy demand at constant fiber intake. We therefore conclude that the hyperphagia of chronic exercise in humans may be linked with significant gastrointestinal adaptations.

The interaction of hand vibration with oculomanual coordination in pursuit tracking

The effects of high frequency hand vibration (150 Hz) on simultaneous ocular and manual tracking performances were investigated in trained human subjects. First, a zero-order pursuit tracking task was performed with and without direct visual control of the hand. Second, eye tracking of an imaginary target linked to the hand was also performed. The results show that hand vibration significantly alters eye and hand tracking performances when the hand is out of sight. However, when the hand is placed in the visual field, tracking performances are less affected by vibration. Visual cues on limb segments may compensate to some extent for the vibration-induced alteration of proprioceptive information otherwise used to control movements. Eye movements are altered during vibration while the subject is tracking or fixating an imaginary target attached to the hand. These findings explicitly show that hand vibration can perturb oculo-manual coordination control. The present results imply that vibration-induced activity of somesthetic mechanoreceptors is likely to contribute to oculomanual coordination alteration and tracking decrement in vibratory environments. Furthermore, direct visual control of the hand and/or arm may be of particular interest in manipulation tasks executed under vibration.

Hypomagnesaemia in elderly hospital admissions: a study of clinical significance

Serum magnesium estimations carried out on 1576 consecutive elderly patients at the time of hospital admission revealed that 10.7 per cent had a serum magnesium level below 0.7 mmol/l, with 4.4 per cent of the total having a serum level less than 0.65 mmol/l. Hypokalaemia was frequently associated with hypomagnesaemia, for which diuretic therapy was the most commonly found predisposing factor. Outcome of illness, measured at six months in terms of mortality, duration of hospital stay and percentage of patients discharged from hospital, was no worse in patients admitted with hypomagnesaemia than in normomagnesaemic controls.

Analysis of eye tracking movements using innovations generated by a Kalman filter

A simple but efficient algorithm has been developed for computer analysis of eye tracking movements. The program separates smooth pursuit and saccadic eye movements. Separation of the two components is achieved using a two-step process of saccade detection. First, an AR model of the velocity of the smooth component is identified and used to determine a Kalman filter. Secondly the innovation sequence generated by this filter allows saccade detection. The precise beginning and end of each saccade are found using a Hinkley algorithm. Examples are given of analysis procedure for eye tracking of a random moving target. The method proved to be highly reliable and could be easily extended to other eye movements such as nystagmus.

Identical orocecal transit time and serum motilin in hyperthermia and normothermia

Fever, exercise, and exposure to a hot environment can all cause symptoms of gastrointestinal dysfunction as they elevate body temperature. Nonetheless, the link between hyperthermia per se and these symptoms is unknown. To test the functional significance of increased body temperature, we investigated the influence of substantial passive hyperthermia on orocecal transit in 12 young, healthy men. Transit time was determined by a consistent rise in H2 concentration in a rebreathing apparatus after oral ingestion of 0.7 g lactulose/kg body weight. Lactulose was given in combination with a 350-ml liquid meal (360 kcal). After raising core temperature in warm water to 38.3 degrees C, orocecal transit time was identical to control (90 +/- 13 min at 38.3 degrees C, 92 +/- 13 min at 37.1 degrees C). While hyperthermia did elevate heart rate and minute ventilation, serum motilin, gastrin, and cortisol were similar in the two conditions. The failure of a passive core temperature rise to alter mouth-to-cecum transit suggests that this aspect of alimentary function is independent of body temperature.

Modulation of cutaneous flexor responses induced in man by vibration-elicited proprioceptive or exteroceptive inputs

The effects of muscle tendon or skin vibration on the early and late components of polyphasic cutaneous responses elicited in the flexor carpi radialis by electrical stimulation of the radial nerve at the wrist were studied in the human, with all muscles at rest. Both early and late flexor responses were enhanced by flexor vibration and depressed by extensor vibration; facilitation was accompanied by a reduction of latency. Furthermore, when an "antagonist vibration response" was present, inhibition of the flexor reflexes was replaced by a facilitation. Palm skin vibration depressed both components of the flexor reflex, while dorsal or "back-hand" skin vibration induced either a facilitation or an inhibition. In addition, back-hand vibration modified the location of the sensations evoked by electrical stimulation of the nerve. In all cases, vibratory stimulus attenuated the perceived intensity of the electrical stimulus. These observations indicate that proprioceptive or exteroceptive information can modulate the gain of the cutaneous reflex loops in a flexible way, under supraspinal control. These data also suggest a possible impairment of the protective withdrawal reflex under vibratory environmental conditions at rest and eventually in active muscles.

The magnesium load test: experience in elderly subjects

While serum magnesium is the simplest and most widely used approach to the evaluation of magnesium status, it is recognized that a normal serum level can occur in the presence of tissue depletion. The magnesium load test is a reliable indirect method of assessing whole body magnesium status, but experience with its use in older subjects is limited. The initial aim was to establish a range of results for the magnesium load test in older subjects who were likely to be tissue depleted. Such data would enable more accurate interpretation of the test in older subjects with normal serum levels who might be tissue-magnesium depleted. Magnesium loading was performed in 43 female subjects, average age 83 years, with serum magnesium levels not exceeding 0.75 mmol/l (mean 0.63 +/- 0.09 mmol/l) and lower than recommended dietary magnesium intakes. Magnesium sulphate was given intravenously, 0.25 mmol magnesium/kg body weight at a rate of 2.5 mmol/hour. Twenty-four-hour urine magnesium was determined for two days before the test and on the day of test from the start of the infusion. The test was abandoned in 13 other subjects because it was not possible to obtain three consecutive accurate urine collections despite careful selection. In the remaining 30 subjects, average magnesium retention was 62% (range 15-98%). Serum magnesium appeared a better guide to tissue status than urine magnesium, but creatinine clearance correlated better with the degree of magnesium retention than either serum or urine magnesium levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac arrhythmias associated with upper gastrointestinal endoscopy in elderly subjects

Continuous Holter monitoring was performed before, during and after upper gastrointestinal endoscopy in 50 unselected, consecutive elderly patients (median age 80 years: range 68-89). In contrast to other studies the patients received no atropine or opiate premedication and were monitored for a prolonged period usually 24 hours after endoscopy. Comparison of a control period when the patient was lying at rest before endoscopy with the period of endoscopy itself revealed an increased frequency of arrhythmias during endoscopy. Forty-eight per cent of patients developed a new arrhythmia or an increased frequency of existing arrhythmia during endoscopy. All arrhythmias were short and self-terminating. Evidence of cardiac disease conferred a significantly increased risk of developing an arrhythmia during endoscopy.

Orocecal transit during mild exercise in women

Little is known of the influence of exercise on movement of ingested food through the alimentary tract or of the association of several gastrointestinal hormones with transit rate in exercise. In this study, orocecal transit during mild exercise was measured in 21 women by detecting a rise in expired H2 after ingestion of 20 g lactulose in a 350-ml (360 kcal) liquid meal. Motilin, gastrin, and cortisol were measured in peripheral venous blood when, as evidenced by a breath H2 rise, the first portion of the meal arrived at the cecum. Comparison was made between seated rest and a treadmill walk at 5.6 km/h up a 2% grade. The walk predictably elevated heart rate, O2 uptake, and rectal temperature and also reduced transit time from 98 min at rest to 75 min during exercise (P less than 0.001). Faster transit in exercise was associated with a significant rise in cortisol, while gastrin and motilin levels were both unchanged. In conclusion, in women mild concurrent exercise accelerates orocecal transit rate of at least the first portion of nonabsorbable carbohydrate in a liquid meal. Although the mechanism for the effect remains unknown, it may be secondary to some aspect of the stress response to physical activity.

The incidence of communication disorders in dysphagic patients

A retrospective study investigated the incidence and types of communication problems in 115 patients referred for swallowing difficulties. Each patient had a bedside swallowing evaluation completed as well as a screening of communication abilities. A formal speech-language evaluation was done when warranted and possible. Of the 115 patients, 93 had suspected swallowing problems based on the bedside evaluation done by the speech-language pathologist. Videofluoroscopy was performed on 85 of these patients. A significant positive correlation was found between communication impairments and both suspected and videofluoroscopically confirmed dysphagia. Cognitive problems were the most frequent communication impairment with dysarthria being second. Neurological diseases were the most common medical diagnoses in patients with swallowing difficulties. The case is presented for the speech-language pathologist to be the primary diagnostician and manager of both communication and oral-pharyngeal swallowing disorders whether they co-occur or not.

Characterization of a rat myosin alkali light chain gene expressed in ventricular and slow twitch skeletal muscles

Mammalian cardiac muscle contains two myosin alkali light chains: 1) the atrial light chain (MLC1A), and 2) the ventricular light chain (MLC1V) predominantly expressed either in the atrium or in the ventricle. In this report we describe the isolation and characterization of the complete gene for rat MLC1V. The rat MLC1V gene is approximately 6.5 kb long and the mRNA coding sequences are organized in 7 different exons. Comparison of this gene sequence with other known MLC1 gene sequences revealed that the exon-intron organization is highly conserved within the MLC1 gene family. The derived protein sequence of rat MLC1V showed a higher sequence homology with human ventricular (96%) MLC1V than with rat fast skeletal MLC1f (74%), suggesting functional similarities between different MLC1V proteins. S1 nuclease mapping and primer extension analysis demonstrated that this gene is expressed only in ventricular and slow twitch skeletal muscle tissues and is transcribed from the same promoter and transcription initiation site.

Scanning electron microscopic study of hemodynamically induced tears in the internal elastic lamina of rabbit arteries

A scanning electron microscopic investigation of tears in the internal elastic lamina of the afferent artery of experimental arteriovenous fistulae was undertaken to determine their site of initiation and to elucidate their nature. Carotid-jugular arteriovenous fistulae and contralateral common carotid arteriotomies were performed in rabbits sacrificed from two to 63 days post-operatively. Following de-endothelialization, scanning electron microscopy of the internal elastic lamina revealed predominantly transverse straight tears with sharp margins. Even in chronic fistulae the tears retained their sharp margins despite their propagation. No evidence of repair was observed. The tears commenced by rupture of the elastic trabeculae traversing the fenestrae. Enzymatic digestion of the internal elastic lamina did not resemble the hemodynamically induced tears and no evidence of elastolytic enzyme activity was detected. The tears suggest that the abnormally stressed elastic tissue has undergone some structural alteration leading to a reduction in its tensile strength.

Regulation of myosin heavy-chain gene expression during skeletal-muscle hypertrophy

Changes in the myosin phenotype of differentiated muscle are a prominent feature of the adaptation of the tissue to a variety of physiological stimuli. In the present study the molecular basis of changes in the proportion of myosin isoenzymes in rat skeletal muscle which occur during compensatory hypertrophy caused by the combined removal of synergist muscles and spontaneous running exercise was investigated. The relative amounts of sarcomeric myosin heavy (MHC)- and light (MLC)-chain mRNAs in the plantaris (fast) and soleus (slow) muscles from rats was assessed with cDNA probes specific for different MHC and MLC genes. Changes in the proportion of specific MHC mRNA levels were in the same direction as, and of similar magnitude to, changes in the proportion of myosin isoenzymes encoded for by the mRNAs. No significant changes in the proportion of MLC proteins or mRNA were detected. However, high levels of MLC3 mRNA were measured in both normal and hypertrophied soleus muscles which contained only trace amounts of MLC3 protein. Small amounts of embryonic and neonatal MHC mRNAs were induced in both muscles during hypertrophy. We conclude that the change in the pattern of myosin isoenzymes during skeletal-muscle adaptation to work overload is a consequence of changes in specific MHC mRNA levels.

Genomic structure and amino acid sequence domains of the human La autoantigen

La is an autoimmune RNA-binding protein of 47 kDa that plays a role in the transcription of RNA polymerase III. Both genomic and complementary DNAs were isolated that encompass the coding sequence of the human La molecule. The genomic clones encompass 11 exons and a putative G/C-rich promoter upstream of the mRNA start site. The cDNA sequence encodes a protein of 408 amino acids and can be divided into two structural domains based upon amino acid content and protease sensitivity. An unusually long stretch of 130 amino acids, much of which was predicted to form a stable alpha-helix, was found near the middle of the protein between the two domains. A ribonucleoprotein (RNP) consensus sequence was found just NH2-terminal to the long alpha-helix. The RNP consensus sequence is split into two exons by the fifth intron. Expression of three separate fragments of the La protein in Escherichia coli showed that a strongly autoimmune-reactive portion resides in the fragment containing the RNP consensus sequence and most of the long alpha-helical core. Autoantibodies from La patients also reacted with the terminal regions of the protein, but the extent of reactivity varied among patients. Differences in reactivity of autoantibodies to each portion of La protein may reflect an evolution of recognition of different epitopes during the development of the autoimmune response. These findings support an antigen-driven mechanism for autoimmune reactivity.

Influence of genotype on nicotine-induced increases of plasma corticosterone in mice as a result of acute nicotine pretreatment

Acute exposure to nicotine produces an elevation of plasma corticosterone levels in rodents. The consequences of repeated exposure to nicotine administered intraperitoneally (IP) were examined in three inbred strains of mice, DBA/2Ibg, C3H/2Ibg and A/J. These strains of mice have been shown previously to differ in a variety of behavioral and physiological responses to acute nicotine exposure. Mice were administered saline or 1.00 mg/kg nicotine IP, followed 30 min later by a range of nicotine doses (0.25-1.00 mg/kg). Strain differences were observed for the dose-response to the second injection; however, no effect of acute nicotine pretreatment was demonstrated. The observed lack of desensitization was consistent across genotype. An intragastric administration of a pretreatment dose of nicotine (4.00 mg/kg) also failed to produce desensitization to a subsequent IP nicotine injection in any strain. Increasing the time interval between injections to 45 min did not alter the CCS response. However, at 90 min between injections, a supersensitive CCS response was measured in all strains.

Genetic differences in plasma corticosterone levels in response to nicotine injection

Changes in plasma corticosterone (CCS) levels following intraperitoneal injections of nicotine were measured in four inbred mouse strains: DBA/2Ibg, C57BL/6Ibg, C3H/2Ibg, and A/J. In all four strains, nicotine produced a dose-dependent (0.5-2.0 mg/kg nicotine) increase in plasma CCS levels which peaked 10-30 min after injection. Saline increased plasma CCS levels in C57BL, A, and C3H, but not in DBA mice. After correcting for plasma CCS levels produced by saline injection, the nicotine-induced rise in plasma CCS was significantly lower for the C57BL strain than for the other three strains tested. These mouse strains also varied in their responses to saline injection with the rank order: C57BL greater than A = C3H greater than DBA. However, the two most divergent strains (C57BL and DBA) did not differ in the effects of a cold water stress. The response to nicotine was completely inhibited by mecamylamine in two strains tested (C3H and C57BL) whereas the response to saline injection was unaffected, suggesting that only the response to nicotine was mediated by nicotinic receptors. It is clear that elevations in plasma CCS induced either by saline injection or by nicotine are influenced by genetic factors.

Hypomagnesaemia in elderly digitalised patients

Hypomagnesaemia and hypokalaemia are known to predispose to digoxin toxicity. Elderly patients receiving diuretics may be at special risk. A 12-month survey of all patients receiving digoxin at the time of admission to our Geriatric Assessment Unit revealed 16% were hypomagnesaemic, whereas no patient was hypokalaemic. There is a need for greater awareness of the risk of magnesium depletion in elderly patients receiving concurrent diuretic and digoxin therapy.

Classical genetic analysis of GABA-related seizures

Differences in resistance to 3-mercaptopropionic acid (MP)-induced seizures exist between DBA/2Ibg and C57BL/6Ibg inbred strains of mice; C57BL/6Ibg mice are more resistant to MP-induced seizures. To determine the mode of inheritance for seizure resistance, a classical genetic analysis was conducted using these two parental strains, their F1, F2, and backcross generations. Latencies to seizure onset and tonus after intraperitoneal (IP) injections of MP (25-40 mg/kg) were quantified. For all populations mean latencies to onset and tonus decreased in a dose dependent manner with the hybrid generations exhibiting a seizure resistant phenotype resembling the C57BL/6Ibg strain. In general, female mice were less resistant to MP-induced seizures than males; however, a significant degree of resistance was retained by the C57BL/6Ibg females and their female progeny. A quantitative assessment of the pattern of inheritance for seizure resistance using a weighted least-squares regression approach indicated that an additive-dominance model explained latency to seizure onset data at 25, 35 and 40 mg/kg. However, at 30 mg/kg, the model required the addition of an epistatic parameter to best describe mean scores at this dose. The results of these analyses suggest that resistance to MP-induced seizures is transmitted in a dominant manner.

Supine position and sleep loss each reduce prolonged maximal voluntary ventilation

Because of the prevalence of supine posture and sleep deprivation in both health and disease, we wondered how each of them influences prolonged maximal voluntary ventilation (MVV). Accordingly, we compared 12-second, 1-min, and 10-min isocapnic MVV supine with that measured in the upright posture in 8 healthy subjects. MVV decreased 6-10% supine, independent of test duration (p less than 0.01). Although end-expiratory lung volume was 0.47 liter lower during supine resting breathing (p less than 0.001), end-expiratory lung volumes during short-term MVV maneuvers were identical. To investigate any additional effect on MVV due to sleep loss, 12 healthy subjects performed 12-second, 1-min, and 30-min isocapnic MVV maneuvers in the supine position, either after normal sleep or after a 24-hour sleepless period. Sleep deprivation reduced MVV by 7-14%, again independent of test duration (p less than 0.05). Sleep loss also reduced the ventilation chosen to represent a submaximal (75%) breathing effect (p = 0.05), and it increased subjective ratings of fatigue and confusion (p less than 0.01). We conclude that supination and sleep deprivation together decrease both short- and long-term MVV by nearly 20%, with impairment of supination not caused by lung volume changes, and with the sleep loss effect occurring in tandem with a rise in the subjective assessment of breathing effort.

Diuretic-associated hypomagnesemia in the elderly

Serum magnesium concentration was measured in 320 consecutive elderly patients (mean age, 81 years) receiving diuretic therapy at the time of hospital admission. When compared with serum concentrations of 250 elderly patients who were not taking diuretics at the time of hospital admission, only the group taking thiazide diuretics had a significantly reduced mean serum level. The 24-hour urine sampling from representative subgroups demonstrated impaired magnesium-conserving ability in hypomagnesemic subjects receiving loop and thiazide diuretic therapy. Patients taking therapy that included a potassium-sparing diuretic had no significant evidence of reduced magnesium-conserving ability. Dietary assessments of the study population revealed suboptimal magnesium intake in the diet.

Gastrointestinal transit during mild exercise

Although exercise is often recommended as therapy for constipation, almost nothing is known of the effects of exercise on rates of movement of material in the gastrointestinal tract. In this study we investigated the influence of mild exercise on transit of a liquid meal from the mouth to the large intestine. Orocecal transit time was determined by a consistent elevation of H2 concentration in a rebreathing apparatus after ingestion of 30 g lactulose; the lactulose was part of a 360-kcal, 350-ml liquid meal. Comparison of transit time was made, in 12 young healthy subjects, between seated rest and a treadmill walk at 5.6 km/h up a 2% grade. The walk elevated heart rate from 64 +/- 4 to 109 +/- 5 beats/min, O2 uptake (VO2) from 0.29 +/- 0.02 to 1.20 +/- 0.07 l/min STPD, and final rectal temperature from 37.0 +/- 0.1 to 38.3 +/- 0.1 degrees C (all P less than 0.01). Exercise speeded transit of the liquid meal, with mean rises in H2 concentration taking place 66 +/- 10 min after ingestion at rest, compared with 44 +/- 6 min after food intake during exercise (P less than 0.02). H2 concentrations in the rebreathing apparatus showed similar base lines in the two experiments, and quantitative increases in H2 concentration, although shifted in time by exercise, were otherwise identical. Subjects with the slowest resting transit rates showed the largest exercise effects (r = 0.79, P less than 0.05). These results indicate that mouth-to-cecum transit of at least the first portion of a liquid meal-based nonabsorbable carbohydrate marker is significantly accelerated during mild exercise.

Inhibitory effects of combined agonist and antagonist muscle vibration on H-reflex in man

Vibration alters human sensory motor performance. Changes in the excitability of spinal reflex mechanisms may be responsible for the majority of the observed alterations. We studied the differential effects of vibration locally applied to gastrocnemius soleus and tibialis anterior muscles separately and to both muscles simultaneously. From the results, it is deduced that combined agonist and antagonist muscle vibration may lead to summative interaction between pre- and postsynaptic inhibition at motoneuronal level. Whole-body vibration is taken to mean a combination of synchronous vibrations applied locally and simultaneously to several muscles. The results also demonstrate that the level of inhibition of the H-reflex resulting from the vibration is directly related to the displacement amplitude of the vibration, regardless of the frequency.

Pyrexia in infection in the elderly

This prospective study investigated the common belief that pyrexia is frequently absent in elderly patients with infection. Oral temperature was closely monitored using both a mercury and an electronic thermometer in 150 ill elderly patients (mean age 81 years) of whom 80% were new admissions to this Unit. A scoring system was devised, based on investigation results and excluding temperature, to assess objectively the likelihood of infection. Seventy-one patients (47%) had 'definite' infection: 95% were pyrexial. A further eight of the nine patients with probable infection were pyrexial. There were no significant differences in mean temperature or other indices of infection between those who died of their infection and those who survived. Ten per cent of all pyrexias were detected only on the electronic thermometer, not on mercury measurement. In 12% of pyrexial patients, the pyrexia first appeared more than 12 h after temperature measurement started. With effective monitoring, pyrexia is detectable in the vast majority of infected elderly patients.

Ventilatory and treadmill endurance during acute semistarvation

Little is known about respiratory muscle function in acute undernutrition, although an inadequate caloric intake is common in numerous disease states. Twelve young-adult, healthy female volunteers performed two familiarization experiments and were then studied after 7 days of consuming 40% of normal daily caloric intake as well as after 1 wk of normal caloric intake. In each experiment subjects performed tests of resting pulmonary function, inspiratory muscle strength, and ventilatory endurance, the last of which involved two 60-s and two 6-min isocapnic maximum voluntary ventilation maneuvers. Subjects then walked to exhaustion in 8-20 min on a treadmill. The caloric restriction did not affect performance of any breathing test but did lower endurance time in severe treadmill exercise (P less than 0.05). Basal metabolic rate was lowered, resting blood levels of free fatty acids and beta-hydroxybutyrate elevated, and glucose lowered following the caloric restriction (P less than 0.05). Blood lactate levels were lower during and after exercise following caloric restriction (P less than 0.05). We conclude that ventilatory muscle strength and endurance are fully preserved in caloric restriction severe enough to cause mild ketoacidosis and hypoglycemia, lowered basal metabolic rate, and decreased endurance in severe treadmill exercise.

Echocardiographic diagnoses in elderly patients with systolic murmurs and cardiac disease

M-mode and 'real-time' echocardiography was employed to study 100 elderly with systolic murmurs and cardiac disease. Technically adequate recordings were obtained in 89 patients. Independent assessment of the echocardiographs showed good reproducibility. Aortic sclerosis was the most prevalent lesion, but did not by itself impair left ventricular function. The echocardiographic diagnosis of mitral regurgitation was significantly related to heart failure and atrial fibrillation. A link between murmur and cardiac disease was postulated in 40% of cases.

Stress hormonal response to exercise after sleep loss

While prolonged loss of sleep is unpleasant and demanding, it remains unclear if it blunts or enhances the physiological stress imposed by subsequent exercise. To investigate this, we deprived eight subjects of sleep prior to exercise to see if this altered the stress hormonal response to that exercise. In a first series of experiments, two fragmented nights of sleep preceded 30 min of heavy treadmill walking exercise. While sleep loss disturbed mood before and during exercise (p less than 0.05), it left stress hormonal levels (cortisol and beta-endorphin) in blood identical to control. In a second series, subjects performed light treadmill walking exercise for 3 h after 36 sleepless hours. As before, sleep deprivation disturbed mood before and throughout exercise (p less than 0.05), but failed to change blood levels of stress hormones. In both series, sleeplessness left heart rate, oxygen uptake, minute ventilation, and body core temperature unchanged in exercise. We conclude that sleep loss provokes psychological changes during subsequent exercise without measurably altering the stress hormonal response to that exercise.

Familial Hodgkins disease

Three cases of Hodgkins Disease in one family are described. The index case presented with pyrexia of unknown origin and the diagnosis of Hodgkins Disease was made at post mortem. Two other members of the family had died of a similar cause many years previously. Triple occurrence of Hodgkin's Disease within one family is very uncommon as is a long time interval between cases.

Heterogeneity of myosin isozyme content of rabbit heart

A detailed study was carried out to measure the relative contents of V1 and V3 myosin isozymes in different regions of rabbit ventricle as a function of age, to assess animal-to-animal variability, and to compare different experimental approaches aimed at minimizing the effects of such variability. In addition, comparisons were made in normal developing hearts between ventricular isozyme composition and myofibrillar myosin calcium-stimulated adenosine triphosphatase. V1 isozyme predominated relative to V3 isozyme in the hearts of 2-week-old rabbits, decreasing to become a minor component in 10-week-old animals. Despite this trend, there was considerable variability in relative isozyme content of whole ventricular tissue among different rabbits of the same age. This variability was reduced in comparisons of littermates and by use of cardiac biopsies to measure changes in isozyme content in the same animal over time. Within different regions of a given heart, there also were small but significant differences in the percent V1 isozyme. The percent V1 was greatest for right ventricular papillary, followed by right ventricular free wall and then the left ventricle (free wall plus septum). There also were differences in the percent V1 within those regions, as exemplified by the significantly higher values for ventricular epicardium vs. endocardium. There was a linear correlation between the myofibrillar myosin calcium-stimulated adenosine triphosphatase and percent V1 of total isozyme for both right and left ventricles in normal and developing hearts. The regression lines for calcium-stimulated adenosine triphosphatase vs. percent V1 had a steeper slope in the left than in the right ventricle.

Inspiratory muscle training in patients with chronic obstructive pulmonary disease

To investigate the effects of inspiratory muscle resistive loading training (IMT) on exercise performance in chronic obstructive pulmonary disease (COPD), 13 patients undergoing standard pulmonary rehabilitation were divided into control (n = 6) and experimental (n = 7) groups. Prior to training, we measured inspiratory muscle strength and endurance, resting pulmonary function, and exercise performance on a bicycle ergometer (a progressive test and an endurance test at two thirds of maximal work load). We then determined their resistive loads for training by measuring their 10-min maximal sustainable resistance. Training by patients in the experimental group involved inspiring against a predetermined resistive load. The control subjects breathed through a sham training tube, so that studies were performed in double-blind fashion. The training consisted of 15-min sessions twice daily for 4 wk. The IMT dramatically improved inspiratory muscle endurance--represented as either sustainable inspiratory pressure (SIP) or endurance time at 60% of maximal inspiratory mouth pressure (Pimmax) at functional residual capacity. The SIP of the trained group increased from 29 +/- 11 to 46 +/- 11% of Pimmax (p less than 0.005). Training slightly increased inspiratory muscle strength (p less than 0.05), as determined by Pimmax. In contrast, resting pulmonary function and performance of both progressive and constant-load exercise remained unchanged. We conclude that 4-wk IMT in a pulmonary rehabilitation setting improves inspiratory muscle endurance in patients with COPD without changing pulmonary function or exercise performance.

Maximal ventilation after exhausting exercise

It remains unclear whether the hyperpnea of exercise severely stresses the ventilatory musculature. We hypothesized that the ability to ventilate maximally is decreased during and immediately following exhausting exercise. Subjects performed isocapnic maximal voluntary ventilations (60-s MVV) before, during the final minute, and after exhausting treadmill exercise lasting either 3-10 min or 60 min. Severe exercise lasting 3-10 min failed to change the 60-s MVV. In contrast, during the final minute and 5 and 10 min after 60 min of exhausting exercise, eight non-runners showed significantly lower (P less than 0.01) 60-s MVV values in comparison to control values. Eight runners had a lower (P less than 0.05) 60-s MVV 10 min post-exercise as compared with control and exercise values. Our data suggest that the capacity to ventilate maximally declines only in long-term exhausting exercise and that this decrement in most pronounced in non-runners.

Normal pressure hydrocephalus and Paget's disease of bone

Although senile dementia of Alzheimer type (SDAT) is the commonest cause of dementia in the elderly, it is important to recognise potentially reversible causes such as normal pressure hydrocephalus. This has been reported to occur in association with Paget's disease of the skull, but would appear to be an extremely rare complication of this disease. To date 4 cases of successful surgical intervention in normal pressure hydrocephalus complicating Paget's disease of skull have been reported. We report 3 cases which have presented to one Department of Geriatric Medicine during a 3-year period. Two cases were diagnosed prior to death and both responded well to ventriculo-peritoneal shunting.

The economy of isometric force development, myosin isoenzyme pattern and myofibrillar ATPase activity in normal and hypothyroid rat myocardium

Hypothyroidism was induced in Wistar-Kyoto rats by adding propylthiouracil to the drinking water (0.8 mg/ml). Initial heat, total activity-related heat, and resting heat rate were measured in left ventricular papillary muscle preparations of propylthiouracil-treated and control rats contracting isometrically at 12 beats/min (21 degrees C), using Hill type, planar vacuum-deposited bismuth and antimony thermopiles. In the propylthiouracil preparations, relative to control, time-to-peak tension increased from 288 +/- 27 (mean +/- SD) to 411 +/- 25 msec (P less than 0.001), dp/dtmax decreased from 38.3 +/- 9.5 to 20.4 +/- 3.5 g X mm-2/sec (P less than 0.001), and peak developed tension decreased from 6.11 +/- 1.75 to 4.64 +/- 0.89 g X mm-2 (P less than 0.05). In the propylthiouracil preparations, initial heat was significantly (P less than 0.001) reduced by 27 or 43% when normalized to peak twitch tension or tension-time integral, respectively. In experiments where the papillary muscles were tetanized, the slope of the linear function of total activity-related heat versus tension-time integral was decreased by 43% (P less than 0.001) in the propylthiouracil preparations, indicating an improved economy of isometric tension maintenance. The predominant myosin isoenzyme of the left ventricular wall, as well as the papillary muscle myocardium, was the V3 variety in the propylthiouracil animals, in contrast to V1 in the controls. Myofibrillar actomyosin calcium-magnesium-stimulated adenosine triphosphatase activity was significantly (P less than 0.02) decreased from 55 +/- 18 (control) to 31 +/- 8 nmol inorganic phosphate ion/mg X min (propylthiouracil).(ABSTRACT TRUNCATED AT 250 WORDS)

Respiratory frequency and the oxygen cost of exercise

Although many studies indicate that the spontaneous breathing frequency minimizes breathing work, the consequences of this for exercise energetics have never been investigated. To see if the spontaneous exercise breathing frequency minimizes oxygen uptake, we compared VO2 during treadmill walking (2/3 VO2 max) at several alternative frequencies. The alternative frequencies ranged from the lowest sustainable to a frequency twice the spontaneous value. All eight subjects adjusted tidal volume to comfort. Exercise oxygen uptake was constant, independent of breathing frequency. At the same time, minute ventilation rose to be 65% greater at the highest frequency than at the lowest (P less than 0.01). We then reproduced the various exercise frequencies, tidal volumes, and ventilations during seated isocapnic hyperpnea to measure VO2 with locomotory muscles at rest. Once again, oxygen uptake was constant, independent of breathing frequency. We conclude that the spontaneous exercise breathing frequency fails to minimize VO2 during either exercise or resting reproduction of exercise ventilation.