The interaction of Tetrahymena 30S dynein with bovine brain microtubules

The binding of Tetrahymena 30S dynein to bovine brain microtubules has been examined. The dynein was bound by its B-end or ATP sensitive site with a stoichiometry of 1 dynein arm per 6 tubulin dimers. Addition of ATP released virtually all the dynein from the surface of the microtubule. Following hydrolysis of the ATP, the dynein reassociated with the microtubule.

Behaviour of the Bilby, Macrotis lagotis (Reid), (Marsupialia : Thylacomyidae) in Captivity

The behaviour was observed, in captivity, of the bilby Macrotis lagotis, a fossorial bandicoot of central Australia. Most of the observations were made at night, but some were of below-ground behaviour during the daylight hours. Bilbies proved to be relatively passive in comparison with other bandicoots, and a rigid dominance hierarchy amongst males was maintained without destructive fighting. Dominant males chased subordinate males out of and away from burrows and the alpha male maintained priority of access to all the well used burrows in the enclosure. Males scent-marked around burrows; the dominant male usually marked over scents left by other bilbies. Males shared burrows freely with females, and copulation appears to take place down burrows. Information is also given on female-female and mother-young behaviour, and some suggestions are made concerning the social structure of wild bilbies. Activity cycles, feeding behaviour, etc. are described.

Colles' fracture and subsequent hip fracture risk

The prevention of hip fractures, a major cause of morbidity and mortality in the elderly, is hampered by insufficient knowledge of the population at risk. A Colles' fracture associated with minor trauma is indicative of an overall 50% increase in the risk of a subsequent hip fracture. The relative risk of a subsequent hip fracture is greater for men with Colles' fracture (RR = 6.4) than for women (RR = 1.3). Among women, the risk is increased more than twofold for those whose Colles' fractures occurred at the age of 70 or older but is not increased for younger women. That greater predictive power was not achieved may be due to differences in the pathophysiology of osteoporosis at various fracture sites.

Changes in bone mineral density of the proximal femur and spine with aging. Differences between the postmenopausal and senile osteoporosis syndromes

We measured bone mineral density (BMD) of the proximal femur, lumbar spine, or both by dual photon absorptiometry in 205 normal volunteers (123 women and 82 men; age range 20 to 92 yr) and in 31 patients with hip fractures (26 women and 5 men; mean age, 78 yr). For normal women, the regression of BMD on age was negative and linear at each site; overall decrease during life was 58% in the femoral neck, 53% in the intertrochanteric region of the femur, and 42% in the lumbar spine. For normal men, the age regression was linear also; the rate of decrease in BMD was two-thirds of that in women for femoral neck and intertrochanteric femur but was only one-fourth of that in women for lumbar spine. This difference may explain why the female/male ratio is 2:1 for hip fractures but 8:1 for vertebral fractures. The standard deviation (Z-score) from the sex-specific age-adjusted normal mean in 26 women with hip fracture averaged -0.31 (P < 0.05) for the femoral neck, -0.53 (P < 0.01) for the intertrochanteric femur, and +0.24 (NS) for the lumbar spine; results were similar for 5 men with hip fractures. By contrast, for 27 additional women, ages 51-65 yr, with only nontraumatic vertebral fractures, the Z-score was -1.92 (P < 0.001) for the lumbar spine. Thus, contrary to the view that osteoporosis is a single age-related entity, our data suggest the existence of two distinct syndromes. One form, "postmenopausal osteoporosis," is characterized by excessive and disproportionate trabecular bone loss, involves a small subset of women in the early postmenopausal period, and is associated mainly with vertebral fractures. The other form, "senile osteoporosis," is characterized by proportionate loss of both cortical and trabecular bone, involves essentially the entire population of aging women and, to a lesser extent, aging men, and is associated with hip fractures or vertebral fractures or both.

Use of sodium nitroprusside in complications of gestational hypertension

Sodium nitroprusside is a potent and ultrafast-acting antihypertensive agent. Limited clinical experience and uncertainty about toxicity have restricted its use in obstetrics. The authors have used nitroprusside concomitantly with hemodynamic monitoring in 4 obstetric patients with severe pregnancy-induced hypertension unresponsive to conventional therapy. The patients with acute congestive heart failure and pulmonary edema responded rapidly and dramatically to nitroprusside. No signs of fetal distress associated with lowering of the arterial pressure were observed, and significant cyanide levels were not detected in a fetal cord blood sample. Nitroprusside should be reserved for refractory hypertensive emergencies in pregnancy. Hemodynamic monitoring is required for adjusting nitroprusside administration and fluid balance. In short-term usage, the authors' experience suggests that maternal and fetal toxicity may not be serious concerns.

Ethyl chloride: a two-week inhalation toxicity study and effects on liver non-protein sulfhydryl concentrations

Male and female Fischer 344 rats (6/sex/exposure concentration) and male beagle dogs (2/exposure concentration) exposed to 0, 1600, 4000 or 10 000 ppm ethyl chloride (EtCl) for 6 hr/da, 5 da/wk for 2 weeks showed no toxicologically significant treatment-related effects on body weights; clinical chemistry, hematology, or urinalysis parameters; neurology (dogs only were examined); gross pathology or histopathology. The only treatment-related differences in organ or relative organ weights (in rats or dogs) were slight, but statistically significant increases in liver to body weight ratios of male rats exposed to 4000 or 10,000 ppm EtCl (4.9 and 7.5% respectively). Liver non-protein sulfhydryl (NPSH) concentration was measured in male Fischer rats and male B6C3F1 mice that were exposed for 6 hours to 0, 1600, 4000 or 10,000 ppm EtCl (mice were exposed to 0 or 4000 ppm EtCl only). Liver NPSH, measured 1/2 hr post exposure, was less than control values in 4000 ppm exposed rats (88% of control value), 4000 ppm exposed mice (64%), and 10,000 ppm exposed rats (89%). The slight decreases in rat liver NPSH seem consistent with the increased liver to body weight ratios. The toxicity data indicate that 2-week repeated exposures to EtCl concentrations that were up to 10 times the current A.C.G.I.H. T.L.V. (1000 ppm) caused minimal treatment-related effects in dogs and rats.

Incidence of Colles' fracture in a North American community

In a 30-year period, 1,137 adult residents of Rochester, Minnesota experienced 1235 Colles' fractures. Fracture incidence among women increased over sixfold between ages 35-39 and 60-64 and then leveled off. Male rates were lower in every age group and did not rise as dramatically. Fractures associated with moderate trauma were responsible for the increased incidence with age and the excess among women. Overall, Rochester rates were 30 per cent or more greater than those reported from communities in other countries (Am J Public Health 1982; 72:605-607.).

1,25-Dihydroxyvitamin D3: short- and long-term effects on bone and calcium metabolism in patients with postmenopausal osteoporosis

We evaluated the effects of therapy with a small dose (0.5 microgram/day) of 1,25-dihydroxyvitamin D3 in 12 previously untreated patients with postmenopausal osteoporosis. Combined radiocalcium kinetic and balance studies showed that at base line, net calcium absorption (mean +/- SEM) was low (7 +/- 3%), calcium balance was negative (-59 +/- 22 mg/day), and bone resorption rate (297 +/- 40 mg/day) exceeded bone formation rate (239 +/- 36 mg/day). After short-term therapy (6-8 months), calcium absorption was normal (27 +/- 3%, P less than 0.001 for difference from base line), calcium balance had improved (+2 +/- 26 mg/day, P less than 0.05), and bone resorption rate (195 +/- 35 mg/day, P less than 0.01) had decreased more than bone formation rate (197 +/- 26 mg/day, NS). Compared with base-line values, after long-term therapy (2 years) the increased level of calcium absorption was maintained (27 +/- 3%, P less than 0.001), but calcium retention declined to a level intermediate (-27 +/- 24 mg/day, NS) between base-line and short-term treatment values, and both bone resorption rate (294 +/- 33 mg/day, NS) and bone formation rate (267 +/- 34 mg/day, NS) increased. Urinary hydroxyproline excretion was lower than before treatment (26.3 +/-2.0 mg/day) after both short-term (21.1 +/- 1.6 mg/day, P less than 0.001) and long-term (22.0 +/- 1.8 mg/day, P less than 0.01) treatments. Trabecular bone volume was 11.3 +/- 1.0% at base line and increased to 16.0 +/- 1.2% (P less than 0.01) after long-term treatment. By contrast, the eight patients studied before and after 6-8 months of placebo treatment had no significant change in any variable.

Panosteitis in a cocker spaniel dog

A 12-month-old, desexed female Cocker Spaniel had intermittent bilateral foreleg lameness which was due to panosteitis of the radius and ulna. The disease was in the active 'middle' state. Endosteal and periosteal new bone formation was demonstrated by histological examination and accounted for the diffuse osteosclerotic appearance of the radial and ulnar diaphyses seen on radiographs.

Subchronic dermal toxicity study of trichlorobenzene in the rabbit

Groups of five male and five female New Zealand albino rabbits were treated by skin application with either 0 (distilled water control), 30, 150 or 450 mg/kg undiluted trichlorobenzene (ICB) for 5 days/week for four weeks. No treatment related systemic effects were observed at any of the treatment levels when body weight, clinical chemistry and organ weight parameters were measured. Systemic effects due to dermal application of TCB were present only in rabbits given 450 mg/kg/day. These effects included a slight but statistically significant increase in the urinary coproporphyrin excretion in males and slight pallor of the liver at gross necropsy in both sexes. Localized effects at the site of application were present in all treated rabbits. These effects were characteristic of the response to dermal irritation. Grossly, the fur was matted by a fine white bran-like scales with variable degrees of erythema, fissures, erosions and ulcers. Histopathologically, there was inflammation and thickening of the epidermis. The size of the affected area varied directly with the dose level. Based on the results of the study, it was concluded that a dose level of 450 mg/kg/day of TCB applied dermally to rabbits induced slight systemic toxicity. The no-observable effect level for systemic toxicity was 150 mg/kg/day when TCB was applied to the skin of male and female rabbits over the course of 30 days.

Terbutaline and maternal cardiac function

The effect of terbutaline sulfate on left ventricular size and performance was studied by M-mode echocardiography in pregnant women with premature labor. Patients with uterine activity initiated during either oxytocin challenge testing or induction of labor served as a comparison group. During terbutaline therapy, heart rate, ejection fraction, and cardiac output increased significantly. End-diastolic volume and systolic blood pressure (BP) were unchanged, and diastolic BP and end-systolic volume fell. No changes in echocardiographic or hemodynamic parameters were present during oxytocin-induced uterine activity. Terbutaline, as currently used to prevent premature labor, is a potent inotropic and chronotropic agent. Pulmonary edema accompanying terbutaline treatment is probably not due to cardiac failure.

The intermetatarsal nerve: a microscopic evaluation

Microscopic evaluation of the interdigital neuroma is difficult because the appearance of the normal nerve has not been described precisely. In an effort to characterize the normal interdigital nerve, 104 nerves were removed at autopsy from the intermetatarsal spaces of 14 women who were more than 48 years old. A positive relationship between perineurial width and internal diameter of the nerve fascicle in web spaces 2, 3, and 4 was defined. In addition, the number and the diameter of blood vessels had a positive correlation in all web spaces. These measurements should be of help in the objective differentiation of the common interdigital neuroma from the normal interdigital nerve.

Retardation of endochondral ossification at the distal ulnar growth plate in dogs

Bilateral forelimb deformities associated with retained cartilage cores in the distal ulna were diagnosed in 8 immature giant breed dogs. Five of the dogs were autopsied. Histopathological examination of the distal ulnar growth plate revealed a localised central thickening due to the accumulation of hypertrophic chondrocytes which had failed to undergo the usual development to degeneration. Also the intercellular matrix septa of this cartilage were not calcified. Projections of the abnormal cartilage even persisted into the primary spongiosa. These abnormalities in the process of endochondral ossification of the growth plate produced the lesion of retained cartilage core which was responsible for the development of forelimb deformity.

Total replacement arthroplasty of the first metatarsophalangeal joint

A surface replacement prosthesis for the first metatarsophalangeal joint has been designed to be used in arthritic conditions of this joint. The components are made of stainless steel and polyethylene and fixed with methylmethacrylate. The surgical details of insertion are important in such a complex, small joint. In the series of 20 patients (21 joints), the patient and physician satisfaction rate was 81% at an average follow-up period of 43 months (range 16 to 58 months). Current use of this prosthesis is most reasonable in older patients with painful degenerative arthritis of the first metatarsophalangeal joint and minimal joint imbalance.

Fixation of metacarpal and metatarsal fractures in greyhounds

Over a 6-year period a total of 23 greyhounds and 10 dogs of other breeds were presented with metacarpal and metatarsal fractures. While in other breeds trauma was the usual cause, in greyhounds the injuries were stress or fatigue fractures. In the greyhounds the fractures occurred mainly in young dogs and were often comminuted. Fifteen cases involved the fifth metacarpal bone of the left foreleg. The fractures were managed by either external immobilisation (8 cases) or internal fixation, mainly with lag screws (14 cases). Of 16 dogs which recovered sufficiently to be trialled, 6 were retired due to poor performance, 2 suffered further fractures and 4 raced in less than 10 races each. Four dogs entered in more than 10 races each won 23 of a total of 109 starts.

Radiographic measurements of the normal adult foot

Various radiographic measurements of the normal adult foot have been reported in both early and recent literature; however, a complete description of radiographic quantitative data has yet to be reported. The purpose of this study is to describe the range of the normal foot using standard radiographic techniques that can be applied to the clinical setting. This should provide the data necessary for the accurate interpretation of foot radiographs. This study demonstrates the wide variation in bony relationships of the normal adult foot. When certain recognized criteria of radiographic measurements were evaluated, some were found to be defined as too narrow or inaccurate. Most importantly, because of this wide range, surgical procedures to produce radiographic homogeneity are not indicated. Treatment should be directed specifically toward areas of pain and not radiographic appearance.

Foot and ankle manifestations of Reiter's syndrome

If one were to characterize the clinical presentation of Reiter's syndrome in the feet and ankles, it would be that of pain associated with mild to moderate swelling and tenderness without significant erythema. These changes would occur most commonly at the posterior calcaneus, metatarsophalangeal joint, and phalangeal regions. The ankles will usually show an effusion. It is very uncommon for the subtalar region, midfoot region, or even the metatarsal shaft area to be involved. Roentgenographic changes were present in similar frequency as in physical findings. Erosions and soft tissue swelling affect the forefoot and ankle while "spurring" and erosions affect the hindfoot. It is readily apparent that no single clinical finding or radiographic change indicates Reiter's syndrome. The type and location of foot pain is what should prompt the physician to seek further elements allowing the diagnosis of Reiter's syndrome.

The effects of autologous bone grafting on bone healing after carpal arthrodesis in the dog

Arthrodesis was performed on the right and left carpus of eight dogs, incorporating a fresh autologous cancellous bone graft in the right carpus. Histological evaluation of each carpus after the procedure demonstrated that although the grafted bone appeared dead, healing was significantly greater (P < 0 . 01) after 12 weeks if it had been used.

Arthrodesis of the interphalangeal joint of the great toe--an improved technique

At the Mayo Clinic between 1950 and 1975, initial fusion of the interphalangeal joint of the great toe was attempted 166 times in 139 patients utilizing a Kirschner wire for stabilization. Follow-up examination of these patients disclosed an overall pseudarthrosis rate of 44%. Because of these disappointing results, a technique involving use of a longitudinal mini-cancellous bone screw was devised which provides increased stability and compression at the arthrodesis site. With this method, used 20 times in 18 patients, the pseudoarthrosis rate was decreased to 10%.

Assessment of block of the sciatic nerve in the popliteal fossa

Success of block of the sciatic nerve in the popliteal fossa in 130 patients was assessed by an anesthesiologist at the time of surgery. The patients were evaluated for complications by the anesthesiologist during postoperative rounds and by the orthopedic surgeon at the 1-month follow-up visit. Acceptance of the block by the patient was judged by answers on a questionnaire filled out by the patients after they had gone home. The questionnaire was designed to determine satisfaction with the block, discomfort associated with performance of the block, and whether sensations suggestive of paresthesias or other complications not evident at the time of discharge from the hospital had occurred. Of 119 patients responding to the questionnaire, 105 (88.2%) expressed overall satisfaction with the anesthesia. Two patients described sensations compatible with postoperative paresthesias, and two others described sensations that may have been paresthesias; in none did the sensations last longer than 1 month. Assessment of the blocks by the anesthesiologist in all 130 patients in the study revealed that anesthesia satisfactory for completion of the operative procedure was achieved in 107 (82.3%). General anesthesia was needed in eight patients (6.2%), and in 15 patients (11.5%) intravenous sedation or injection of the site of surgical incision with local anesthesia (or both) was needed.

Treatment of primary osteoporosis with fluoride and calcium. Clinical tolerance and fracture occurrence

Thirty-six patients with primary osteoporosis were treated for up to six years with sodium fluoride, calcium supplements, and, in 24 patients, vitamin D. Major adverse reactions (synovitis, painful plantar fascial syndrome, recurrent vomiting, or anemia) occurred in 15 patients (42%). New vertebral fractures occurred at a rate of 329 fractures per 1,000 years of observation. Almost half of them occurred during the first year of therapy, and they were only one sixth as frequent in 12 patients who had fluoride-induced increased trabeculation on vertebral roentogenograms. Nevertheless, until long-term safety and antifracture efficacy are better established, this regimen should continue to be restricted to investigational use.

Spatial and Temporal Use of Habitat by the Red-necked Pademelon, Thylogale thetis (Marsupialia : Macropodidae)

Use of habitat by 10 red-necked pademelons was studied by radio-tracking in an area of rain forest that adjoined pasture. They consistently moved at nightfall to pasture, where they grazed until their return to the rain forest shortly before daybreak. The time of movement between habitats was highly predictable and varied seasonally with changes in daylength. Nocturnal and diurnal range areas are described within the total area occupied by each individual. They rarely moved from the forest edge more than 70 m onto pasture or 500 m into rain forest. Animals were not nocturnal and travelled widely through the rain forest by day, seeking food and sites for basking. The nocturnal and diurnal partitioning of habitat is seen as a strategy for exploiting the rich food resource of pasture while maximizing the probability of avoiding predators.

Total joint arthroplasty. The foot

A prosthesis has been designed with which to resurface the painful, degenerated first metatarsophalangeal joint. Clinical evaluation thus far has indicated satisfactory results in 16 of 18 instances. This procedure will probably give the best results in the older patient with hallux rigidus, but the length of follow-up is as yet too short to allow firm opinions to be formed.

Chevron osteotomy for hallux valgus

The chevron osteotomy for realignment of the first metatarsal head in metatarsus primus varus deformity has been utilized at the Mayo Clinic since 1976 on 26 feet (18 patients). Follow-up evaluation disclosed excellent relief of pain, good cosmetic correction, and overall patient satisfaction. Radiographic evaluation demonstrated reduction in the angle between the phalanx and the metatarsal bone of the great toe as well as narrowing of the forefoot with a decreased angle between the first and the second metatarsal bones. The stability of the osteotomy, the technical ease, and the absence of secondary difficulties such as transfer metatarsalgia make this procedure preferable when osteotomy of the distal portion of the first metatarsal bone is used for correction of moderate deformity.

Subungual exostoses

From 1910 through 1975, forty-four patients with subungual exostoses were seen at the Mayo Clinic. Thirty-four of them had the exostosis on the great toe. Forty-three of the patients were treated by local excision and one was treated by amputation of the hallux. Five patients had local recurrence. None of the tumors underwent malignant change. Histologically, the tumors consisted of a proliferating fibrocartilaginous gap that merged into mature trabecular bone at its base. The growth in the cap was so active that is sometimes mimicked sarcoma, but no true anaplasia was seen. The subungual exostoses were uniformly benign, and local excision was the treatment of choice.

The frequency of bone abnormality in patients on anticonvulsant therapy

Biochemical and bone morphometric measurements were evaluated in 12 patients who were on long-term anticonvulsant therapy with barbiturates. Half of the patients had no symptomatic bone disease, and half presented with bone disease and pain. Serum biochemical values were normal except for a few patients who had an elevated serum level of parathyroid hormone; the concentration of serum 25-hydroxy vitamin D was decreased in the majority of patients in whom it was measured. Bone absorptiometric values were normal but proved to be misleading: the Singh Index and videodensitometric measurements indicated that bone mass was below normal in all patients. Bone morphometric data indicated that bone resorption was 3 times greater than normal, and there was no evidence of osteomalacia. Vitamin D and possibly calcium have been suggested as potentially useful agents in the treatment of the bone disease associated with chronic anticonvulsant therapy.

Intermediate states of subfragment 1 and actosubfragment 1 ATPase: reevaluation of the mechanism

The kinetics of the increase in protein fluorescence following the addition of ATP to subfragment-1 (SF-1) and acto-SF-1 have been reinvestigated. The concentration dependence of the rate obtained with SF-1 did not fit a hyperbola and at high ATP concentration, approximately 40% of the signal amplitude was lost due to a fast phase at the beginning of the transient (20 degrees C). At lower temperature (less than or equal to 10 degrees C) the fluorescence transient was biphasic, with a fast phase observed at high ATP concentration. These results indicate that there are two steps in the SF-1 pathway in which there is a change in protein fluorescence. Measurements of ATP binding and hydrolysis by chemical quench-flow methods indicate that the rate of ATP binding is correlated with the fast fluorescence step and hydrolysis is correlated with the slow fluorescence change. The SF-1 mechanism can thus be described as: (formula: see text) where M represents SF-1 and states of enhanced fluorescence are given by M (16%) and M (36% enhancement, relative to SF-1). Step 1 is a rapid equilibrium with K1 approximately 10(3) M-1. Tight binding of ATP occurs in step 2 and the loss of signal amplitude requires k2 greater than or approximately 1500--2000 s-1. The maximum observed fluorescence rate defines the rate of hydrolysis, k3 + k-3 = 125 s-1 (20 degrees C, 0.1 M KCl, pH 7.0). The steps in the mechanism correspond to the Bagshaw--Trentham scheme, with the important difference that the assignment of rate constant is altered. Formation of the acto-SF-1 complex gave a fluorescence enhancement of approximately 14% relative to SF-1. Dissociation of acto-SF-1 by ATP produced a 20--22% enhancement in fluorescence. There was no detectable fluorescence change during dissociation as evidenced by a lag in the fluorescence transient which corresponded to the kinetics of dissociation. The fluorescence change occurred at the same maximum rate as for SF-1 but there was no loss in signal amplitude at high ATP concentration. The kinetics of the fluorescence change corresponded to the rate of ATP hydrolysis, whereas tight ATP binding occurred at a much faster rate in approximate agreement with the rate of dissociation. Thus the fluorescence change in the acto-SF-1 pathway corresponds to step 3 in the SF-1 mechanism. The complete scheme can be described as follows: (formula: see text) where AM represents acto-SF-1. The tight binding step in the SF-1 pathway (k2) is sufficiently fast so that a similar step (k2') in the acto-SF-1 pathway could precede dissociation but the AM-ATP intermediate has not been detected. Following hydrolysis on the free SF-1, actin recombines with M.ADP.Pi or possibly with a second SF-1 product intermediate as proposed by Chock et al. (1976) and the fluorescence returns to the original AM level with product release.

Percutaneous biopsy of the iliac crest

By use of a percutaneous trephine, a relatively large (7.5-mm diameter), full-thickness bone sample can be obtained from the iliac crest under local anesthesia. Such a specimen can be used for histologic evaluation as well as small-volume, bone-grafting procedures. Patient acceptance has been excellent.