Motor units and histochemistry in rat lateral gastrocnemius and soleus muscles: evidence for dissociation of physiological and histochemical properties after reinnervation

A reexamination of the question of specificity of reinnervation of fast and slow muscle was undertaken using the original "self" nerve supply to the fast lateral gastrocnemius (LG) and slow soleus muscles in the rat hindlimb. This paradigm takes advantage of the unusual situation of a common nerve branch, which supplies both a fast and slow muscle, and of the opportunity to keep the reinnervating nerve in its normal position. In addition it provides a test of the effects of cross-reinnervation among muscles of the same functional group. The properties of soleus and LG muscles and of individual muscle units were characterized in normal rats and in rats 4-14 mo after cutting the lateral gastrocnemius-soleus (LGS) nerve and suture of the proximal stump to the dorsal surface of the LG muscle. Individual muscle units were functionally isolated by stimulation of single motor axons to LG or soleus muscle contained in teased filaments in the L4 and L5 ventral roots. Motor units were classified as fast contracting fatiguable (FF), fast contracting fatigue resistant (FR), and slow (S) on the basis of criteria described in the cat by Burke et al. and applied to rat muscle units by Gillespie et al. Muscle fibers were classified as fast glycolytic (FG), fast oxidative glycolytic (FOG), and slow oxidative (SO) on the basis of histochemical staining for myosin ATPase, nicotinamide-adenine dinucleotide diaphorase (NADH-D), and alpha-glycerophosphate (alpha-GPD). Reinnervated muscles developed less force and weighed less in accordance with having fewer than normal motor units and having lost denervated muscle fibers. Normal LG contained a small proportion of S-type motor units (9%), whereas the majority (80%) of control soleus units were S type. After reinnervation, each muscle contained similar proportions of fast and slow motor units with S-type units constituting 30% of units in both muscles. When compared with the normal motor-unit sample, there was no significant change in average twitch and tetanic force in reinnervated muscles for each type of motor unit. However, the range within each type was greater, and there was considerable overlap between types. Twitch contraction time was inversely correlated with force in normal and reinnervated muscles as shown previously in self- and cross-reinnervated LGS in the cat. Changes in proportions of motor units in reinnervated LG were accompanied by corresponding changes in histochemical muscle types. This contrasted with reinnervated soleus in which the proportion of muscle fiber types was not significantly changed from normal despite significant change in motor-unit proportions.(ABSTRACT TRUNCATED AT 400 WORDS)

The role of titratable acidity in acid aerosol-induced bronchoconstriction

We evaluated the importance of pH, titratable acidity, and specific chemical composition in acid aerosol-induced bronchoconstriction in 8 asthmatic subjects. We administered aerosols of HCl and H2SO4 at pH 2.0 in an unbuffered state and buffered with glycine. The buffered acids were given in order of increasing titratable acidity (defined as the number of ml of 1 N NaOH required to neutralize 100 ml of acid solution to pH 7.0). Each set of buffered or unbuffered acid aerosols was given on a separate day and each aerosol was inhaled through a mouthpiece during 3 min of tidal breathing. Bronchoconstriction was assessed by measurement of specific airway resistance (SRaw) before and after inhalation of each aerosol. SRaw increased by more than 50% above baseline in 1 of 8 subjects after inhalation of unbuffered HCl and in no subjects after inhalation of unbuffered H2SO4, even at pH 2.0. In contrast, SRaw increased by greater than 50% in all 8 subjects after inhalation of HCl and glycine at pH 2.0 and 7 of 8 subjects after inhalation of H2SO4 and glycine at pH 2.0. The mean titratable acidity required to increase SRaw by 50% above baseline was calculated for each challenge by linear interpolation; these values for H2SO4 and glycine (5.1 ml of 1 N NaOH) and HCl and glycine (2.2 ml of 1 N NaOH) were slightly, but significantly, different (p = 0.01) and were considerably higher than the titratable acidity of the unbuffered acids at pH 2 (1.0 ml of 1 N NaOH).(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of reinnervation and motor unit recruitment in human hand muscles after complete ulnar and median nerve section and resuture

Following complete ulnar or above-elbow median nerve sections, there was no significant correlation between motor unit size (twitch amplitude) and recruitment threshold, as assessed by spike triggered averaging. This absence of orderly recruitment was attributed to misdirection of motor axons during regeneration. Following median nerve section at wrist level, where the reinnervated muscles have more synergistic actions, orderly recruitment by size appeared to be re-established. Thus, the size principle of motor unit recruitment can be re-established after nerve section in humans, if motor axons innervate their original muscles or ones with closely synergistic functions.

Drinking and mortality. The Albany Study

The relation of alcohol consumption to mortality was examined in a cohort of 1,910 employed men aged 38-55 years, enrolled in the Albany Study, a prospective investigation of factors related to cardiovascular disease. Two follow-up periods were examined, one between 1953-1954 and 1971-1972 and the other after 1971-1972. In both periods, there was a positive relation between the rate of alcohol consumption and noncoronary heart disease death, not assignable to any specific cause. Coronary heart disease death was not associated with drinking during the initial follow-up but was negatively associated with drinking in the later follow-up. All-cause mortality was positively associated with alcohol consumption in the earlier follow-up, because of the greater cigarette use among drinkers, but not in the later follow-up. There was a significant positive relation of drinking to deaths from liver cirrhosis and diabetes but not to deaths from motor vehicle accidents.

Acetylcholine receptors and sodium channels in denervated and botulinum-toxin-treated adult rat muscle

1. The number of acetylcholine (ACh) receptors and Na channels was measured in adult rat hind-limb muscles after denervation or injection of botulinum toxin type A (BoTX), using specific binding of radiolabelled neurotoxins. 2. Denervation by sciatic nerve section increased the number of [125I]iodo-alpha-bungarotoxin ([125I]BTX) binding sites from low, unmeasurable levels to 39 +/- 3 fmol of toxin bound per milligram muscle protein at 21 days. 3. Subcutaneous injection of BoTX produced complete neuromuscular blockade for 11-14 days over which time the number of [125I]BTX binding sites increased with the same time course and to the same extent as following denervation. 4. Neither denervation nor BoTX treatment significantly altered the number of tritiated saxitoxin ([3H]STX) binding sites from normal values of 7.8 fmol/mg muscle weight or 57 +/- 3 fmol/mg homogenate protein. This may, however, correspond to a lower density of [3H]STX sites in the muscle membrane. 5. It was concluded that neuromuscular blockade with BoTX is equivalent to denervation in its effects on synthesis of ACh receptors. Numbers of Na channels are more stable than ACh receptors but may also be modulated by neuromuscular activity.

Hydroxyurea inhibits airway hyperresponsiveness in guinea pigs by a granulocyte-independent mechanism

Exposure of guinea pigs to toluene diisocyanate (TDI) causes an increase in airway responsiveness to inhaled acetylcholine. This increased airway responsiveness is temporally associated with an increase in polymorphonuclear leukocytes (PMN) in the tracheal wall. To determine whether PMN play a mechanistic role in this increase in acetylcholine responsiveness, we studied the effects of PMN depletion on this response with 2 different cytotoxic drugs, hydroxyurea and cyclophosphamide. Airway responsiveness was measured in untreated, hydroxyurea-treated, or cyclophosphamide-treated animals while they breathed spontaneously or during mechanical ventilation through a tracheostomy. In untreated animals, exposure to TDI caused a significant increase in airway responsiveness to acetylcholine for both spontaneously breathing and anesthetized and ventilated animals. This TDI-induced increase in airway responsiveness was associated with a significant influx of PMN into both the extravascular and intravascular trachea. Treatment with hydroxyurea, to reduce PMN counts in the bloodstream to less than 200/mm3, inhibited both the TDI-induced increase in airway responsiveness and the TDI-induced influx of PMN into the trachea of both spontaneously breathing and mechanically ventilated animals. In mechanically ventilated animals, treatment with cyclophosphamide, until PMN counts in the bloodstream were less than 200/mm3, also inhibited the influx of PMN into the trachea but did not inhibit the TDI-induced increase in airway responsiveness. These results suggest that PMN are not necessary for the TDI-induced increase in airway responsiveness and that hydroxyurea inhibits this effect by a mechanism other than PMN depletion.

Nonlinear stiffness--force relationships in whole mammalian skeletal muscles

Small, sinusoidal length changes were superimposed on isometric contractions of fast- and slow-twitch mouse muscles, which were stimulated maximally via their nerves. Stiffness increased with increasing frequency of sinusoidal stimulation, but the relative time course of force and stiffness changes during twitch, tetanic, or partially fused contractions was quite invariant over a range of frequencies in both muscles. Typically, stiffness increases more rapidly than force during contraction and decreases less rapidly during relaxation. This pattern was observed at various temperatures and with various numbers of stimuli. It can be described by a nonlinear relation between stiffness and force with some hysteresis. The presence in the muscle of parallel and series elastic elements, whose stiffness varies with force, may account for the nonlinear relation. This nonlinearity can be used to relate the patterns for summation of force and stiffness observed with brief trains of stimuli under a variety of conditions.

Rapid development of cerebral atrophy in systemic lupus erythematosus

A 21-year-old female is described who developed severe cerebral lupus 9 months after the onset of her disease. A dramatic change in her CT brain scan from normal to gross cerebral atrophy was observed in the month following onset of her cerebral disease. This patient developed hepatitis during the course of her hospitalization. This is an unusual manifestation of systemic lupus. The patient's serum also contained anti-Sm antibodies. This is a relatively infrequent finding in the serum of lupus patients outside the United States.

Meningitis caused by Streptococcus suis type II

A 49 year old head porter developed meningitis shown to be caused by Streptococcus suis type II. The rare human infections with the organism, a pathogen of pigs, usually occur in those employed handling pig meat and are associated with auditory or vestibular dysfunction.

Axotomy affects calcium-sensitive potassium conductance in sympathetic neurones

Following peripheral nerve section, the cell body and proximal axon undergo various physiological and morphological changes which may be associated with regrowth. We found that axotomy reduced the amplitude and duration of the afterhyperpolarization (AHP) of the action potential (AP) of bullfrog sympathetic neurones. In addition, the repolarization of the AP was slowed. The Ca2+-channel blocker, Cd2+ (200 microM) produced similar effects in normal cells by blocking the Ca2+-sensitive K+ conductances (gK, Ca) which contribute to the AHP and to AP repolarization. Although Ca2+-channel function was preserved after axotomy, Cd2+ did not affect axotomized neurones. This suggests that axotomy promotes a functional loss of gK, Ca which could reflect a regenerative response of the cell to injury.

Organization of motor units following cross-reinnervation of antagonistic muscles in the cat hind limb

Peripheral reorganization of nerve and muscle properties was studied following misdirection of regenerating axons to foreign muscles. The tibial nerve, which innervates all of the distal extensor muscles, was cross-united with the common peroneal nerve, which innervates all of the distal flexor muscles, in one hind limb of seven 2-6 month old cats. After 18-24 months the properties of the motor units in the reinnervated triceps surae muscles were studied by dissection and stimulation of the ventral root filaments. The normal size relationships were re-established in reinnervated medial gastrocnemius (m.g.) and lateral gastrocnemius-soleus (l.g.s.) muscles in so far as motor unit force was directly correlated with the extracellularly recorded amplitude of the axon potential and with contractile speed. The range of sizes of motor units in reinnervated m.g. and l.g.s. muscles was similar to normal, both in terms of the muscle unit size (determined by measuring tetanic tension) and axon size (determined from the amplitude of the extracellularly recorded action potential). The amplitude of the axon potentials in the crossed nerves was weakly correlated with calculated conduction velocities because of the variation in the conduction delays across the suture line. As axon potential amplitude is a direct function of axon size at the recording site, it provided a reliable measure of regenerating axon size. Motor units were classified as slow (s.), fast fatigue resistant (f.r.), fast intermediate (f.i.) or fast fatigable (f.f.) by their contractile speed and fatigue properties. Tetanic tensions generally increased from slow to fast units with s. less than f.r. less than f.i. less than f.f. in reinnervated and normally innervated muscles, but the overlap between different unit types was considerably greater in reinnervated muscles. Thus, peripheral reorganization of nerve and muscle properties according to size can occur in reinnervated muscles, irrespective of the source of the regenerating nerves.

Innervation and function of hind-limb muscles in the cat after cross-union of the tibial and peroneal nerves

Peripheral nerves to flexor (common peroneal) and extensor (tibial) nerves in a hind limb of seven 2-6 month old cats were cut and cross-united to study the plasticity in the spinal cord. The extent to which motoneurones from extensor and flexor motor pools were misdirected to their antagonistic muscles was determined by measuring the potentials generated at the spinal roots from the crossed nerves. The axons contributing to the extensor nerves normally leave the cord in the L7 and S1 ventral and dorsal roots while the axons contributing to the flexor nerves normally leave the cord in the L6 and L7 ventral and dorsal roots. Following cross-union, medial gastrocnemius (m.g.) and lateral gastrocnemius-soleus (l.g.s.) nerves were primarily supplied by L6 and L7 ventral and dorsal roots, and common peroneal (c.p.) nerves were primarily supplied by L7 and S1 ventral and dorsal roots. A method for quantifying the completeness of cross-reinnervation was developed. The pattern of e.m.g. activity in cross-reinnervated muscles during locomotion was primarily determined by the innervating nerve with the reinnervated flexor muscles being activated during the extensor phase. However, the cross-reinnervated extensor muscles showed evidence of extensor activity in addition to the double-burst pattern typical of flexor nerves. This extensor activity was more prominent when the nerve cross was less complete. We conclude that during locomotion the activity of spinal motoneurones was not substantially modified by inappropriate peripheral connexions, even when the nerve cross was carried out in young animals. This conclusion is discussed in relation to previous studies which suggested some degree of functional modification.

Granulocyte-mediated airway edema in guinea pigs

To determine the role of polymorphonuclear leukocytes (PMNs) in the airway edema that accompanies airway inflammation, we studied the effects of a 1-h exposure to 2 ppm toluene diisocyanate (TDI) on tracheal extravasation of Evans blue dye and on the concentration of PMNs in the tracheal wall. Tracheal Evans blue content was significantly increased by TDI exposure (53.6 +/- 8.0 micrograms/g tracheal tissue (mean +/- SE) for animals exposed to TDI and 16.3 +/- 2.0 for animals exposed to air, P less than 0.0025) as were both the intravascular and extravascular concentration of PMNs in tracheal sections (intravascular PMNs were 28.0 +/- 8.4 X 10(3) cells/mm3 for TDI and 1.5 +/- 1.5 X 10(3) for air, P less than 0.025, extravascular PMNs were 10.9 +/- 4.5 X 10(3) for TDI and 0 for air, P less than 0.05). PMN depletion with vinblastine or with hydroxyurea abolished both the increase in tracheal Evans blue extravasation and the increase in the concentration of intravascular and extravascular PMNs in animals exposed to TDI. PMN depletion with hydroxyurea did not significantly inhibit the increase in tracheal Evans blue extravasation caused by intravenous histamine. Administration of donor PMNs to animals depleted of PMNs with hydroxyurea reconstituted the TDI-induced increase in tracheal Evans blue extravasation (80.4 +/- 17.3 micrograms/g tissue (mean +/- SE) in animals exposed to TDI vs. 21.3 +/- 2.9 in animals exposed to air, P less than 0.025) and in the intravascular concentration of PMNs in tracheal sections [18.5 +/- 3.4 X 10(3) cells/mm3 (mean +/- SE) in animals exposed to TDI vs. 1.3 +/- 1.3 X 10(3) in animals exposed to air, P less than 0.0025].(ABSTRACT TRUNCATED AT 250 WORDS)

Reinnervation of the lateral gastrocnemius and soleus muscles in the rat by their common nerve

To determine whether there is any specificity of regenerating nerves for their original muscles, the common lateral gastrocnemius soleus nerve (l.g.s.) innervating the fast-twitch lateral gastrocnemius (l.g.) and slow-twitch soleus muscles was sectioned in the hind limb of twenty adult rats. The proximal nerve stump was sutured to the dorsal surface of the l.g. muscle and 4-14 months later, the contractile properties of the reinnervated l.g. and soleus muscles and their single motor units were studied by dissection and stimulation of the ventral root filaments. Contractile properties of normal contralateral muscles were examined for comparison and motor units were isolated in l.g. and soleus muscles for study in a group of untreated animals. Measurement of time and rate parameters of maximal twitch and tetanic contractions showed that the rate of development of force increased significantly in reinnervated soleus muscles and approached the speed of l.g. muscles but rate of relaxation did not change appreciably. In reinnervated l.g. muscles, contraction speed was similar to normal l.g. muscles but relaxation rate declined toward the rates of relaxation in control soleus muscles. After reinnervation by the common l.g.s. nerve, the proportion of slow motor units in l.g. increased from 10 to 31% and decreased in soleus from 80 to 31%. The relative proportions of fast and slow motor units in each muscle were the same as the proportions of fast and slow units in the normal l.g. and soleus muscles combined. It was concluded that fast and slow muscles do not show any preference for their former nerves and that the change in the force profile of the reinnervated muscles is indicative of the relative proportions of fast and slow motor units: fast units dominate the contraction phase and slow units the relaxation phase of twitch and tetanic contractions of the muscle.

Alcohol consumption and its relationship to smoking, weight, blood pressure, and blood lipids. The Albany Study

Between 1953 and 1955, a still-ongoing prospective cardiovascular study enrolled 1,910 employed men. Men who drank more alcohol had higher levels of cigarette use, blood pressure, and high-density-lipoprotein cholesterol concentrations. After 18 years of follow-up, the survivors consumed twice as much alcohol, on the average, as they had at entry, weighed slightly more, and had substantially higher blood pressures. Formerly heavy drinkers who had quit, however, lost weight and had less than average blood pressure increases. There was no significant association between changes in smoking habits and changes in drinking habits.

Capitation reimbursement for pediatric primary care

A feasibility analysis of capitation reimbursement for a primarily Medicaid population in The Johns Hopkins Pediatric Primary Care Clinic was conducted. The utilization of all inpatient and outpatient care of 2,261 patients was monitored for a 6-month period. As a result, per capita rates based on charges were determined for each group of patients according to type of insurance. Blue Cross and private insurance patients had capitation rates three times that of the Medicaid patients and over ten times that of self-pay patients This variation in utilization was attributed to the selection of enrollees, the morbidity of the population, and the varying services covered by payor group. Administrative issues regarding establishing a pediatric health maintenance organization are also discussed. Close supervision of house staff in treating patients, including admissions, length of stay, and specialty referral is of utmost importance in containing costs in this clinic setting.

Effect of ozone and histamine on airway permeability to horseradish peroxidase in guinea pigs

Airway permeability was studied in groups of male guinea pigs at 2, 8, and 24 h after a 1-h exposure to 1 ppm ozone or at 2 h after a 1-h exposure to filtered air (control). Intratracheal administration of 2 mg horseradish peroxidase (HRP) was followed by blood sampling at 5-min intervals up to 30 min. The rate of appearance of HRP in plasma was significantly higher at 2 and 8 h after ozone exposure than that found in animals examined 2 h after air exposure or 24 h after ozone exposure. A dose of 0.12 mg/kg of subcutaneous histamine given after the 15 min blood sample significantly increased the already elevated permeability seen at 2 h post ozone, but had no effect on animals exposed to filtered air 2 h earlier or to ozone 24 h earlier. No difference was seen in the amount of subcutaneous radiolabeled histamine in the lungs of animals exposed 2 h earlier either to air or to ozone. These data indicate that a short-term exposure to ozone produced a reversible increase in respiratory epithelial permeability to HRP in guinea pigs. The potentiation of this increased permeability by histamine may be another manifestation of ozone-induced hyperreactivity.

Airway hyperresponsiveness and inflammation induced by toluene diisocyanate in guinea pigs

We examined the changes in airway responsiveness to increasing doses of an acetylcholine aerosol in anesthetized and ventilated guinea pigs 2, 6, or 24 h after exposure to 2 ppm toluene diisocyanate (TDI) or 2 h after exposure to air or 1 ppm TDI. Pulmonary resistance (RL) after the animals inhaled a buffered saline aerosol was used as baseline and was similar for air and TDI groups. The concentration of acetylcholine calculated to cause a 200% increase in RL was significantly lower for animals studied at 2 h (0.68%) or at 6 h (0.77%), but not at 24 h (2.39%), after TDI than for air animals (3.07%). The increase in airway responsiveness in the TDI-exposed animals was associated with histologic changes in the trachea and intrapulmonary airways. Exposure to 2 ppm TDI caused a patchy loss of cilia, shedding of epithelial cells into the airway lumen, and an influx of inflammatory cells into the trachea and other airways. In the lamina propria of the trachea, the concentration of extravascular polymorphonuclear leukocytes (PMN) was 13- to 26-fold greater in animals studied 2 or 6 h after exposure to 2 ppm TDI or at 2 h after 1 ppm TDI than in animals exposed to air. The concentration of PMN in the epithelium was significantly increased only in animals examined 2 h after 2 ppm TDI. Exposure to TDI also caused an influx of eosinophils into the tracheal mucosa. This influx occurred later and was more persistent than the influx of PMN. These results indicate that a single exposure to TDI can cause an increase in airway responsiveness that is associated with epithelial injury and acute airway inflammation.

Drinking and coronary heart disease: the Albany Study

The relation of alcohol consumption to coronary heart disease (CHD) was examined in a cohort of 1910 employed men aged 38 to 55 years enrolled in the Albany Study, a prospective investigation of factors related to cardiovascular disease. Two follow-up periods were examined, one between 1953-54 and 1971-72, the other after 1971-72. In the initial period, there was no clear evidence of a relation between the rate of alcohol consumption and CHD incidence. In the later period, men whose monthly consumption was 60 ounces or more had a lower than average CHD incidence rate. A negative relationship with drinking held for all manifestations of CHD. Other CHD risk factors were examined, special attention being given to cigarette smoking and HDL-cholesterol. The fact that drinking is a matter of choice may introduce some confounding factors. The absence of a relation between drinking and CHD risk in the earlier follow-up suggests the need for caution in interpreting the results.

Temperature effects on the kinetics of force generation in normal and dystrophic mouse muscles

The kinetics of isolated extensor digitorum longus and soleus muscles from normal and genetically dystrophic (129/ReJ dy/dy) mice were studied at temperatures from 8 to 38 degrees C. The rate constants for the exponential rise of tetanic force and for the exponential decay of force during an isometric twitch or short tetanus were similar in normal and dystrophic soleus muscles, but the decay rates were significantly reduced in dystrophic extensor digitorum longus muscles. The temperature dependence for several rate constants for isometric twitches and tetani was similar in all muscles studied, suggesting that the same rate limiting processes apply to fast and slow, normal and dystrophic muscles. Thus, the contractile proteins and those in the sarcoplasmic reticulum of dystrophic muscle are probably normal. The slower relaxation phase in dystrophic extensor digitorum longus muscles is compatible with a reduction in Ca2+-pumping sites in the sarcoplasmic reticulum, perhaps secondary to a change in motor unit composition. Some changes in the temperature dependence for measured times, toward those of soleus muscles, is consistent with the increased proportion of slow twitch motor units in dystrophic extensor digitorum longus muscles.

The relation of drinking and smoking habits to diet: the Lipid Research Clinics Prevalence Study

The relation of cigarette smoking and alcohol use to diet was examined in a general population of adults ages 20-59 years enrolled in the Lipid Research Clinics (LRC) Prevalence Study. There was a positive association between cigarette and alcohol use, but little relation between these habits and the nutrient intake. The total energy from food was about the same whether or not a person drank or smoked; alcohol was simply added to food intake. However, persons who drank received slightly less of their food energy from carbohydrate than persons who did not drink and persons who smoked received slightly more of their food energy from fat than did nonsmokers. Both persons who drank and persons who smoked weighed less than would be expected from their total energy intake. While these relationships were similar for men and women, among women they were stronger for those using gonadal hormones than among those not using these hormones.

Lupus pernio: a clinico-radiological study of thirty-five cases

Thirty-five patients with lupus pernio were observed in a series of 818 patients with clinical and histological evidence of sarcoidosis. This analysis provides the natural history of lupus pernio and its associated clinico-radiographic features. There was intrathoracic involvement in 74% of patients, upper respiratory tract disease in 54%, reticulo-endothelial involvement in 54%, bone cysts in 43% and ocular lesions in 37%. It predominated in West Indies-born women. Histological confirmation was easily obtained by nasal mucosal biopsy and this could be repeated serially to evaluate the response to various treatments. Nasal bone radiographs showed destruction of the nasal bones, porosis and alteration in bone texture. Peripheral bone cysts were evident in 50% of patients who were radiographed, and in about 50% of these patients, the cysts were found in both hands and feet.

Iron pigment in the brain of a man with tardive dyskinesia

A 64-year-old man with bipolar affective disorder developed persistent tardive dyskinesia following an overdose of lithium and haloperidol. Two years later he died of unknown causes. Neuropathologic examination revealed extensive deposition of iron in basal ganglia and substantia nigra.

Ozone-induced airway hyperreactivity in the guinea pig

The predominant airway site and mechanism underlying ozone (O3)-induced respiratory hyperresponsiveness was examined in anesthetized guinea pigs and in vitro tissue preparations. Animals exposed to 1.0 or 1.2 ppm O3 (1 h) demonstrated an enhanced airway response to subcutaneous histamine compared with air-exposed animals. The anatomic site of hyperresponsiveness most likely did not involve the parenchyma, since quasi-static deflationary pulmonary compliance was decreased to a similar extent by histamine in air- and O3-preexposed animals. In contrast, the conducting airways were probably involved as changes in pulmonary resistance elicited by subcutaneous histamine were greater in O3- than in air-exposed animals. Neither atropine nor vagotomy abolished this enhanced responsiveness induced by O3. Although vagal interruption did not alter responsiveness, O3-exposed animals demonstrated greater respiratory responses to efferent electrical stimulation of the vagi than air-exposed animals. This suggests the site of hyperresponsiveness may be located distal to the site of efferent stimulation, possibly in the smooth muscle itself or in its microenvironment.

Drinking and mortality. The Framingham Study

Drinking and subsequent mortality were examined in a cohort of 5,209 men and women from Framingham, Massachusetts. Alcohol histories were obtained at the second biennial examination (1950-1954) from 2,106 men and 2,641 women. Of this group, 646 men and 521 women died in the next 22 years. Unlike what is reported from most other prospective studies, men who drank had lower mortality than men who did not, the lowest mortality being for light drinkers. Even men drinking 60 ounces of alcohol per month or more had no greater mortality than nondrinkers. Drinking by women was unrelated to subsequent mortality. For most alcohol-related causes, there were too few deaths to analyze. Liver cirrhosis, however, accounted for 24 deaths. Although these were related to alcohol use, more than half of the persons dying from this cause reported drinking less than 60 ounces of alcohol per month at baseline. There was, however, a very strong association of heavy alcohol consumption with stomach cancer, but not with any other cancer.

Some difficulties inherent in the interpretation of dietary data from free-living populations

Isocaloric adjustments of diet in metabolic experiments tend to induce negative correlations. In free-living populations, on the other hand, the absolute amounts of major nutrients consumed are positively correlated with total calorie intake and with each other. In general, these positive correlations are fairly strong. Relative amounts of nutrients consumed tend to be weakly and negatively correlated with total calories and each other. Because of these intercorrelations conclusions drawn from cross-sectional population data are ambiguous, at best, and misleading, at worst. Beyond that, the correlation between the intakes of specific nutrients with total calorie intake introduces the possibility that dietary variables may to some degree be surrogates of some nondietary variables; in particular, of physical activity. Unless the questions being asked in population studies are precisely formulated, with a careful consideration of the biological issues and the statistical limitations, biased conclusions are likely to result.

Tuberculous meningitis presenting as an obstructive myelopathy. Case report

Subacute paraplegia progressing over 3 months due to spinal cord compression was the presenting symptom of tuberculous meningitis in this patient with a normal chest x-ray film and no radiological or autopsy evidence of Pott's vertebral tuberculosis. The obstructive myelopathy was the result of proliferative granulomatous meningitis. A review of the literature indicates that this is a very unusual presentation of tuberculous meningitis.

Drinking and its relation to smoking, BP, blood lipids, and uric acid. The Framingham study

Drinking habits and other characteristics were observed for 20 years in a cohort of 5,209 Framingham, Mass, men and women. During this period the average amount of alcohol consumed rose 63%. The percent increase was greater for women than men and greater for younger persons than older. Serum uric acid and phospholipid concentrations were higher at higher levels of alcohol consumption. Lipoprotein levels of 0 to 12 and 100 to 400 Svedberg units were positively associated with alcohol consumption in men but negatively associated with alcohol consumption in women. Blood pressure was higher in nondrinkers than light drinkers, but among drinkers BPs were higher at higher consumption levels. While cigarette smokers had lower BPs than nonsmokers, this seemed to be due to their lower weight. Persons who increased their alcohol consumption during follow-up had a small mean increase in serum phospholipid and uric acid levels, BP, and weight relative to the average changes for these variables.

Drinking habits and death. The Yugoslavia cardiovascular disease study

In a prospective study of more than 10000 Yugoslav men it was found that consumption of alcoholic beverages was inversely related to non-sudden death from coronary heart disease (CHD) and positively related to death from trauma. The consequence was an apparently U-shaped relation between alcohol consumption and death, the lowest mortality being among moderate drinkers. Excess mortality from trauma was evident only among men under 55 and only for those who reported at entry to the study that they had been drunk during the preceding week. Alcohol consumption as reported at entry was unrelated to subsequent mortality from liver cirrhosis or any form of cancer. An enlarged liver, however, was associated with higher death rates for liver cirrhosis. This raises the possibility that some of the men were heavy drinkers preceding their entry to the study but were no longer drinking heavily at the time of entry. Enlarged liver, however, was also related to hypertension and to chronic obstructive pulmonary disease and thus was not a specific indicator of alcohol abuse in this population. Recent drunkenness but not frequency of drinking was related to death from trauma and liver cirrhosis and to sudden CHD death. In short, both the pattern of drinking and the usual level of alcohol consumption appear to be related to mortality in this population.

Relation of diet to LDL cholesterol, VLDL cholesterol, and plasma total cholesterol and triglycerides in white adults. The Lipid Research Clinics Prevalence Study

The association of diet with low density lipoprotein cholesterol (LDL-C) and total triglycerides, as well as with total and very low density lipoprotein cholesterol (VLDL-C), was investigated in a random sample of 4374 white participants aged 20 to 59 years seen by the Lipid Research Clinic Prevalence Study. Carbohydrate and total calories were negatively associated with LDL-C. There was also a statistically significant positive association of LDL-C with the percentage of total calories from fat. These three findings are generally consistent with what other cross-sectional studies have reported for the relation of diet with total cholesterol levels. The only diet variables significantly related to triglyceride levels in both men and women were the percentage of calories from fats, particularly polyunsaturated fatty acids (PFA), the P/S ratio, and the number of grams of PFA per day, all of which were inversely associated with the level of this lipid.

Drinking habits and coronary heart disease: the Yugoslavia cardiovascular disease study

In a prospective study of more than 10,000 Yugoslav men residing in Bosnia and Croatia, who were first examined in 1964--1965, consumption of alcoholic beverages was related inversely to the subsequent appearance of coronary heart disease clinically manifest as myocardial infarction or nonsudden coronary heart disease death. Consumption of alcoholic beverages was not so related to sudden cardiac death. Men who drank most frequently had half the subsequent incidence of overall coronary heart disease as men who seldom or never drank. This finding was true for urban residents only. Serum cholesterol and Quetelet index were also related to coronary heart disease in urban areas but not in rural areas. The inverse relation of alcohol consumption to coronary heart disease incidence was statistically significant even after taking into account differences in blood pressure, serum cholesterol levels, cigarette smoking and other variables. The apparent absence of protection against sudden death may be due to chance or it may reflect the deleterious effects of high alcohol consumption on the myocardial cells and increased vulnerability to lethal arrhythmias in an especially lean population. There is, in fact, a specific association of recent drunkenness with sudden death in this population. Conceivably, the acute effect of heavy drinking may be a dominant factor in the incidence of sudden death for this population.

Temperature dependence of mammalian muscle contractions and ATPase activities

Isolated rat and mouse extensor digitorum longus (EDL) and soleus muscles were studied under isometric and isotonic conditions at temperatures from approximately 8 degrees -38 degrees C. The rate constant for the exponential rise of tension during an isometric tetanus had a Q10 of approximately 2.5 for all muscles (corresponding to an enthalpy of activation, delta H = 66 kJ/mol, if the rate was determined by a single chemical reaction). The half-contraction time, contraction time, and maximum rate of rise for tension in an isometric twitch and the maximum shortening velocity in an isotonic contraction all had a similar temperature dependence (i.e., delta H approximately 66 kJ/mol). The Mg++ ATPase rates of myofibrils prepared from rat EDL and soleus muscles had a steeper temperature dependence (delta H = 130 kJ/mol), but absolute rates at 20 degrees C were lower than the rate of rise of tension. This suggests that the Mg++ ATPase cycle rate is not limiting for force generation. A substantial fraction of cross-bridges may exist in a resting state that converts to the force-producing state at a rate faster than required to complete the cycle and repopulate the resting state. The temperature dependence for the rate constant of the exponential decay of tension during an isometric twitch or short tetanus (and the half-fall time of a twitch) had a break point at approximately 20 degrees C, with apparent enthalpy values of delta H = 117 kJ/mol below 20 degrees C and delta H = 70 kJ/mol above 20 degrees C. The break point and the values of delta H at high and low temperatures agree closely with published values for the delta H of the sarcoplasmic reticulum (SR) Ca++ ATPase. Thus, the temperature dependence for the relaxation rate of a twitch or a short tetanus is consistent with that for the reabsorption rate of Ca++ into the SR.

Drinking habits and other characteristics: the Yugoslavia Cardiovascular Disease Study

In two large general populations of Yugoslav men from Tuzia, Bosnia, and Remetinec, Croatia, examined in 1964-1965, it was found that a greater alcohol consumption was accompanied by higher blood pressures, higher pulse rates, and higher concentrations of serum cholesterol and hematocrit. A greater consumption was also associated with an enlarged liver, as well as a higher prevalence rate of chronic bronchitis and thrombophlebitis. All these were statistically significant even after allowing for differences in cigarette smoking and demographic characteristics. Pulse rate, liver size, and varices appear to be specifically associated with a history of episodes of drunkenness. There were significant differences in drinking habits by place of residence, religious background, years of schooling, and kind of work. These were allowed for in evaluating the relationship of drinking to other characteristics. Two anomalous findings were low prevalence rates for diabetes and gastritis among those drinking most frequently.

Time course and extent of recovery in reinnervated motor units of cat triceps surae muscles

1. Nerve and muscle properties were studied in single motor units of triceps surae muscles in the cat using chronic recording techniques and intramuscular microstimulation. Recordings were made before and at intervals up to 18 months after a nerve was sectioned and sutured either to its distal stump (nerve-nerve suture) or to a muscle directly (nerve-muscle suture). Thus, each nerve and muscle served as its own control for recovery after reinnervation.2. Following a delay all muscles recovered their preoperative tension after nerve-nerve suture with a single exponential having a time constant of 1-2 months. Only half the muscles recovered their preoperative tensions after nerve-muscle sutures. Muscles which did not recover fully also had a slower time course of recovery.3. The estimated number of motor units did not increase significantly later than 2 months after nerve section and suture. Further recovery of muscle tension is due to increased unit tension, rather than increasing numbers of reinnervated motor units. Unit tension recovered completely in all muscles, but did not become enlarged, even when muscles apparently remained partially denervated.4. The latency of compound nerve potentials often recovered completely, although the amplitude of the potential remained depressed. Single motor axonal potentials recovered to control levels after reinnervation of muscle with a time constant similar to that for the recovery of motor unit tension. Therefore, two distinct populations of motor axons contribute to the compound potential: reinnervating axons whose size recovers fully, and disconnected axons which remain atrophic. Incomplete recovery of the compound potential amplitude mainly results from a failure of all axons to remake peripheral connexions.5. Thus, formation of functional nerve-muscle connexions completely reverses the effects of axotomy on nerve and muscle. Reinnervated motor units recovered their preoperative size, whether or not much of the muscle remained denervated.

Ozone inhibition of tissue cholinesterase in guinea pigs

This study sought to determine if ozone at levels known to induce bronchial hyperreactivity in guinea pigs would inhibit tissue cholinesterase activity. Male, Hartley guinea pigs were exposed to filtered air, 0.1 ppm ozone, or 0.8 ppm ozone for 1 hr. Two hours after exposure, brain, lung, and diaphragm tissue samples were frozen for assay of cholinesterase activity. Brain cholinesterase activity was only minimally inhibited in either ozone exposure group. Both levels of ozone significantly inhibited lung cholinesterase activity compared to control animals' activity: a 17% decrease in activity in the 0.1 ppm ozone group (P less than .05) and a 16% decrease in the 0.8 ppm ozone group (P less than .05). Ozone at 0.8 ppm also inhibited activity in the diaphragm by 14% (P less than .02). To determine the degree of involvement of cholinesterase inhibition in bronchial hyperreactivity, parathion pretreated animals were challenged with histamine and the pulmonary function changes monitored. Parathion-treated animals had a peak resistance increase of 330 +/- 104% (mean +/- SE), while the control vehicle animals' increase was 165 +/- 48%. The differences were not statistically significant, but show that cholinesterase inhibition may contribute to ozone-induced bronchial hyperreactivity.

Studies on the morphology of human uric acid stones

Human uric acid acid renal stones are easily distinguished from other urinary calculi by their globular or spherical shape, their colour and their hardness. Investigations of uric acid crystals grown in the presence of a variety of pigments indicate that a disordered layer structure of the uric acid dihydrate is responsible for the colour of such crystals, caused by the inclusion of pigment molecules into the crystal lattice. This in turn may help to explain the other special properties of uric acid stones.

Lipoproteins, cardiovascular disease, and death. The Framingham study

Based on six years of follow-up evaluations of the Framingham, Mass, men and women aged 49 to 82 years, it was found that a low-density lipoprotein (LDL) cholesterol concentration was associated with a low incidence of coronary heart disease (CHD) risk but with a statistically significant excess of stroke incidence in women and of deaths from non-CHD causes in both sexes. There was no suggestion that an elevated HDL cholesterol level was associated with an excess incidence of any of the cardiovascular end points considered or of death. An inverse relation of high-density lipoprotein (HDL) cholesterol level with CHD and its major consequences, CHD death and congestive heart failure, was observed. Triglyceride determinations seem to add little information respecting cardiovascular risk to that elicited from HDL and LDL cholesterol and other known cardiovascular risk factors. While the relation of HDL and LDL cholesterol with CHD is paralleled by findings from a variety of sources, the inverse relation of LDL cholesterol with stroke in women and with death from non-CHD causes requires additional confirmation and exploration.

Alcohol and high-density lipoprotein cholesterol

Associations between alcohol intake and levels of high-density lipoprotein (HDL) cholesterol were examined in 2473 men and 1530 women seen as part of the random sample at visit 2 of the Lipid Research Clinics Prevalence Study. More men than women reported alcohol intake. The alcoholic beverage preference differed by age and sex. The levels of HDL cholesterol were higher in drinkers than in nondrinkers. The statistically significant associations varied somewhat by age; however, the average correlation coefficient was 0.21 for men and 0.25 for women. HDL cholesterol levels were lower in those who reported never drinking alcohol than in occasional drinkers.