[Myonic makeup of the muscles innervated by the vagus nerve].

Histochemical investigation on succinic dehydrogenase activity and morphometric studies have demonstrated certain differences in the dog sublingual group of muscles. The thyreohyoid and sternohyoid muscles innervated by spinal nerves possess three types of myons differing in succinic dehydrogenase activity and in the area of transversal section. The cricothyreoid muscle and the superior pharyngeal constrictor obtaining their motor innervation from the vagus nerve are composed of unitypical muscular fibres with nearly the same areas of transversal section and high enzymic activity. The differences noted should be explained by different sources of motor innervation.


[Reactive changes in the skeletal muscle tissue to the action of the rays of a carbon dioxide laser].

Cross-striated muscular tissue in white rats was studied histologically and morphometrically after the effect of laser. In the first series of the experiment (25 rats) the tongue, musculus masseter and femoral muscles were cut by means of carbon dioxide laser device "Scalpel-1" changing its power within the limits of 20, 40, 60, 80, 100% from maximum (35V). Immediately after the procedure, the pathological focus along the line of the incision had clear borders and consisted of a line of coagulated necrosis and a zone of necrobiosis. Its size was 48-75 mkm and depended on the power of irradiation and on how the laser ray was directed towards the course of muscular fibres. A definite difference was revealed in the size of zones of coagulated necrosis and necrobiosis of lingual myons situating lengthwise and across the axis of the laser ray. In the second series of the experiments (50 rats) regeneration of the tongue and musculus masseter was studied. On the first day, edema and infiltration were insignificant because of coagulation of the blood vessels. Capillaries with the diameter of 20 mkm were forming from the preserved vessels and growing into the granulation tissue. On the second week, young muscular elements appear in the regenerate. Nonresorbted areas of the coagulated tissue impede myonic regeneration. On the 35-40 th day, fine muscular fibres, connective tissue and capillaires of normal size can be found within the traumatic area. The data obtained are compared with the results on reactivity of skeletal muscles after other types of lesions.


[Quantitative analysis of the structural organization of the human ventricular myocardium].

A special technique was worked out in order to study structural organization of the ventricular myocardium (90 human hearts without pathological signs) at macromicroscopical level. It is convenient to estimate spatial orientation of the cardiac contractile elements by the direction of fibrillar fasiculi at definite points. Quantitative characteristics on orientation of myocardial fibrillar fasciculi were obtained according to depth and extension of the cardiac wall in reference to the three-dimentional system of coordinates. Mathematical description of the structural organization of the ventricular myocardium was presented, the cardiac wall was considered as a thick envelope of a complex form. The structural organization was described by means of single vectors, tangents to the fibrillar fasiculi of the myocardium at the points of measurements.


[Change in the myocardial capillary endothelium in the early periods after x-ray irradiation (an electron microscopic study)].

According to the data of quantitative electron microscopic analysis in rats 1-48 h after total x-ray irradiation (450 rad) the number of microvesicles in endothelial capillaries decreases. Increasing size of the microvesicles and appearance of vacuoles does not compensate decreased total transport volume of these structures. After irradiation, in most capillaries the endothelial layer does not change its thickness; neither lesions in intracellular contacts nor formation of holes are observed. Both width of pericapillary zones and total volume of interstitial space in the myocardium do not change during the time of investigation.


[Arterial monoaminocytes of the base of the brain in vertebrates].

By Falck's method monoaminocytes of the arteries in the encephalon base were studied in Teleostei (Anarhichas lupus, Eleginus navaga, Leuciscus brandti Liza soiuy in amphibians (Rana temporaria, Rana semiplicata, Bufo bufo), in reptiles (Testudo horsfiedli, Trionyx chinensis) and in birds (blue rock pigeon, hen). Specific and individual peculiarities in chromaffinocyte, labrocyte and melanophore distribution were revealed in the vertebrate cranial arteries. In all the animals studied chromaffin cells are more frequent in the lateral olfactory artery. Their concentration decreases towards cranial, caudal branches of the internal carotid artery, the main and internal carotid arteries. The greatest amount of chromaffinocytes was found in the cranial arteries of Anarhichas lupus, then comes Eleginus navaga, Leuciscus brandti and Liza soiny Concentration of melanophores in fishes increases with enlargement of the vascular diameter; these cells are more abundant in the arteries of Anarhichas lupus and in less amount in Eleginus navaga, Leuciscus brandti and Liza. Pigmented cells are more abundant in the internal carotid artery and its cranial and caudal branches than in lateral, olfactory and main arteries of fishes. On the contrary, in  amphibians, the main artery contains a maximal concentration of melanophores. In the tortoise cranial arteries, there are only single cells of this type, and birds have no such cells. Labrocytes occur in the greatest concentration in the tortoise cranial arteries and in other vertebrates they are scarce or absent. As a whole, the role of the local endocrine link in regulation of the brain arteries mobility decreases in the following way: fishes--amphibians--reptiles--birds.


[Morphology of gastrointestinal tract tumors induced in rats by N'-nitro-N-nitrosoguanidine].

For 14 months 200 white noninbred male rats received N-methyl-N'-nitro-N-nitrosoguanidine in various concentrations in drinking water. The animals were sacrificed in 18--22 months. Out of 178 rats surviving the time of appearance of the first tumor 64 animals developed tumours of the gastrointestinal tract. Histologically, gastric tumours in 34 cases were presented by adenomatous outgrowths, in 11 the changes were extremely suspect of cancer, in 2 cases morphologically true cancer was observed. The induced gastric tumours had certain peculiarities as compared with the corresponding tumours of man which consisted in tumour cells growing through the thickness of the wall without marked atypism and lack of metastases. Intestinal tumours were sarcomas in which simultaneously some mesenchymal components were present.


[Histo- and cytochemical enzymatic characteristics of breast cancer].

In most of the cases studied, histo- and cytoenzymochemical values of metabolism in cancer of the mammary gland correlate with the histological type, differentiation level and the degree of the tumor malignancy. As the histological degree of malignancy increases and the level of differentiation of the mammary cancer decreases, the activity of glycolysis and pentous shunt enzymes, lactate dehydrogenase and glucose-6-phosphate dehydrogenase, increases and that of the Krebs cycle enzymes, succinate and malate dehydrogenase, as well as the enzyme of glycerophosphate shuttle mechanism and oxidation of glycerol-L-glycerophosphate dehydrogenase decreases simultaneously. These data suggest that histo- and cytochemical methods of the enzyme activity determinations may be used for the specification of the prognosis and choosing of the auxiliary methods for the therapy of the mammary gland cancer based both on morphology and metabolism of the tumour.


[Pathology of the microcirculation in Schönlein-Henoch disease according to morphological and biomicroscopic data].

The state of microcirculation in hemorrhagic vasculitis was studied by morphological methods and conjunctival biomicroscopy. Inflammatory, sclerotic, and ataptative changes in terminal vessels of the internal organs and serous membranes are described. The systemic pattern of vascular pathology and selective vulnerability of the venular part (postcapillaries predominantly) in this disease were demonstrated. Morphological data reflecting the functional insufficiency (decompensation) of the local hemo- and lymph-dynamics are presented. A relative comparability of postmortem and biomicroscopic structural changes in the vessels of the microcirculatory bed was established. The method of conjunctival biomicroscopy is considered to be useful clinically not only for the elucidation of the extent of vasculitis activity but also for the evaluation of the effectiveness of treatment.


[General principles of the electron microscopic analysis of human neoplasms (using the example of studying lung cancer ultrastructure)].

Electron microscopic examinations of lung cancer showed the tumor cells to be capable of specific ultrastructural differentiation owing to which a tumor represents a combination of cells with different degrees of differentiation. This capacity of tumor cells to specific ultrastructural differentiation and formation of tumors consisting of nondifferentiated cells alone or of nondifferentiated and differentiated cells of one or several types, as well as the discovery of differentiated cells simultaneously with signs of cells of two types (chimera cells) suggest that either polypotent (stem cells) or monopotent (precursor cells) cells undergo malignancy. Accordingly, the histogenetic (cytogenetic) appurtenance of a tumor depends not upon its development from one to another type of differentiated cells but upon further direction of differentiation of transformed cells.


[Age-related changes in the cholinergic and adrenergic nerve elements of the human heart and their status in cardiovascular pathology].

Histochemical studies of architectonics and mediator activity of cholinergic and adrenergic nerve plexuses in the myocardium of the auricles and right atrii of the heart were carried out. Both autopsy and biopsy materials: parts of right atrii from patient with congenital and rheumatic defects and atherosclerosis of the coronary arteries, were used. Age changes in the nerve plexus were found to include a decrease in the activity of acetylcholinesterase and the content of catecholamines followed by decreased density of the plexus itself. Perivascular fibrosis combined with changes of afferent and adrenergic elements was revealed. Coronary artery atherosclerosis enhances and aggravates functional and structural changes of cholinergic and adrenergic components of the nervous apparatus of the heart associated with age. Congenital heart diseases are accompanied by decreasing density of adrenergic nerve plexuses and decreased content of catecholamines in them, and rheumatic diseases by destruction of cholinergic and adrenergic components.


[Role of glycosaminoglycans in altering vascular wall permeability for atherogenic lipoproteins].

The relationship between the pattern of distribution of lipoproteins and morphological features of atherosclerotic lesions was demonstrated by histoautoradiographic and histochemical methods in experiments using perfusion in vitro of aortas from atherosclerotic rabbits with atherogenic lipoproteins (LP) labeled in various positions. Accumulation of glycosaminoglycanes (GAG) in the time course of the atherosclerotic process was shown to be the factor contributing to the retention of LP in the vessel wall. At the same time, no GAG accumulation was found in sites of the greatest permeability. Irrespective of the stage of the process, formation of foci of increased permeability was, as a rule, associated with accumulation of poorly differentiated cells. The evidence of primary increase of permeability of the endothelial barrier in the form of activation of the proliferative processes and GAG accumulation was obtained.


[Acid phosphatase in the nerve tissue exposed to local vibration].

The results of examinations for acid phosphatase in the spinal neurons of cats treated by vibration are presented. The animals were subjected to various periods of vibration with parameters of 20 Hz frequency and 2 mm amplitude. The activity of acid phosphatase in the nervous tissue was found to depend upon the duration of vibration: after a short-term treatment the activity of the enzyme was reduced insignificantly, after a long-term treatment a sharp reduction of the enzyme activity was observed in most cells.


[Brain glioblastoma with metastases into the cervical and lumbar lymph nodes].

An observation of cerebral glioblastoma transformed from dedifferentiated astrocytoma with metastasis into cervical and lumbar lymph nodes is presented. Growth of the tumour into the area of scars in dura mater formed after repeated operations for the tumour removal contributed to metastasizing.


[Autoimmune diseases of the salivary glands].

The structural and functional features of the salivary glands and their function associated with the immunocompetent system are described. The disturbance of such association, in the author's opinion, is conducive to the development of a peculiar tumour pathology (adenolymphomas) and autoimmune processes (Sjögren syndrome autoimmune parotitis). Based on the data from the literature two forms of this disease are distinguished: (1) a distinct nosological form developing as a result of various exo- and endogenous injuries, and (2) manifestations of other diseases, as a rule, of the autoimmune genesis accompanied by the secondary involvement of the salivary glands. The morphological picture in both forms is identical. It is suggested that in systemic involvement of the salivary, lacrimal and other glands and some autoimmune disease the term "Sjögren syndrome" be used, and the distinct disease be termed "autoimmune parotitis".


The angiographic pattern of the peripheral retinal vasculature.

Various diseases of the peripheral retinal vasculature, such as sickle cell retinopathy and Eales' disease, demonstrate vascular abnormalities. For comparative purposes, we documented angiographically the peripheral retinal vasculature in young, healthy subjects. Our findings showed the density of the capillary bed to be highest in the posterior pole and least concentrated toward the periphery. Peripheral capillaries are considerably larger than those found posteriorly and have fewer bifurcations. Our technique also detected the periarterial capillary-free zone and the zone without capillaries adjacent to the ora serrata. These aspects were consistent with findings of other investigators using in vitro techniques. By creating a standard of normalcy in vivo, the angiographic technique allows vascular abnormalities evident in diseases of the peripheral retinal vasculature to be more precisely defined and compared.


Ocular Toxocara in siblings of two families. Diagnosis confirmed by ELISA test.

To my knowledge this study of two families with ocular Toxocara is the first in the literature to report involvement of more than one sibling. All four children had far-advanced disease with irreversible loss of macular vision in the affected eye. The clinical findings were confirmed by the ELISA test. With laboratory confirmation of the clinical findings, I expect to find not only more patients in the population at large with ocular Toxocara, but also expect to find numerous siblings in a particular family to be involved as well. Therefore, when ocular Toxocara is found in a child, every sibling in the family should be examined. Just as the young child with amblyopia does not complain of decreased vision, even so the young child with ocular Toxocara often will not complain of any visual problems.


Hyaluronic acid vitreous substitute. A six-year clinical evaluation.

Hyaluronic acid vitreous substitute (HYVISC) was used during 347 operations performed on 294 eyes of 286 patients. It was injected intraocularly in 266 operations (73 scleral bucklings, 175 open-sky vitrectomies, among others) on eyes with complex retinal detachments that were considered inoperable by ordinary surgical techniques. During 81 closed vitrectomies, it was applied extraocularly between the surgical contact lens and the cornea. Hyaluronic acid was found to be well tolerated by human eyes. In eyes that had been given a poor prognosis, scleral buckling with hyaluronic acid tamponade produced reattachment in 16% of the eyes; open-sky vitrectomy, scleral buckling, and hyaluronic acid salvaged 18%. It also appeared helpful in the preservation of corneal epithelial integrity and clarity during closed vitrectomy.


Retinal fluorography using oral fluorescein.

Fluorescein sodium can be administered safely by mouth. The resulting fluorograms are useful in demonstrating many retinal conditions characterized by bright late leakage, such as cystoid macular edema. Oral administration of fluorescein may be preferred in studies of children, patients with difficult veins, and in some surveys of large patient populations.


Arachnoidal cyst invading the orbit.

Ipsilateral glaucoma developed in a 51-year-old man with a left-sided temporal lobe arachnoidal cyst. Ultrasonic examination disclosed a cystic orbital lesion adjacent to the optic nerve. Following intracranial decompensation of the arachnoidal cyst, the intraocular pressure dropped markedly. Ultrasonography showed a collapse of the presumed optic nerve sheath cyst. While the exact mechanism producing glaucoma in this patient remains unclear, there was an apparent relationship between the elevated intraocular pressure and the arachnoidal cyst.


Orbital cellulitis due to Neisseria gonorrhoeae in an enucleated socket.

Orbital cellulitis due to Neisseria gonorrhoeae developed in an adolescent girl in a previously enucleated socket. Since this organism also was isolated from her pharynx, the orbital infection probably resulted from contamination of the prosthesis by gonococci from her mouth, either directly or by transfer from her fingers.


Sino-orbital polyposis.

A 70-year-old woman with a long history of nasal and sinus polyps developed bilateral proptosis and left total external ophthalmoplegia. She was known to have hypercalcemia, which was later discovered to be caused by a parathyroid adenoma. X-ray studies, including computerized tomography, revealed increased radiodensity in the ethmoid sinuses (due to dystrophic calcification from the hypercalcemia), partial absence of the orbital walls from earlier surgical procedures, and bilateral rounded, retrobulbar tumors. At surgery, glistening, yellow, transparent, and encapsulated-lobulated masses were removed from the left orbit; they appeared to have prolapsed through a postsurgical dehiscence in the superomedial orbital wall. Light and electron microscopy confirmed that the lesional tissue represented polyps covered by respiratory epithelium; the yellow color was the consequence of secondary lipidization of the stromal fibroblasts.


Reconstruction by myocutaneous eyelid flaps.

The combined loss of skin and deeper tissues of the eyelids and periorbital regions can frequently be reconstructed with use of an eyelid myocutaneous flap. This technique alone can be used for most eyelid defects not involving the lid margin, or it can be used in conjunction with other procedures when the lid margin is involved. Defects, sometimes quite large, in 37 patients have been reconstructed with good results. The technique provides one-stage reconstruction, avoids volume loss and depressed scars, provides an excellent blood supply to the flap, gives an optimum tissue match, decreases patient morbidity, and increases the likelihood of a good cosmetic result. The generalized applications of this technique make it valuable for reconstructive surgery of the orbital region.


Retinal light exposure from operation microscopes.

Several popular surgical microscopes were measured for source radiance. A method has been devised for calculating patient retinal exposure from these instruments. Retinal irradiance is seen to be surprisingly high, assuming dilated pupils and clear media. It ranges from 0.10 to 0.97 W/sq cm. This is one to ten times higher than that produced by an indirect ophthalmoscope. There is evidence linking light exposure during surgery to cystoid maculopathy (Irvine-Gass syndrome).


The pathology of vitreous hemorrhage. II. Ultrastructure.

We undertook an ultrastructural study of the dual processes of hemolysis and vitreous membrane formation during the resolution of vitreous blood clots in rabbits. Red blood cell degradation began within 24 hours before the onset of the inflammatory response and occurred mainly in the extracellular matrix. Macrophage activity was directed at clearing lysed RBC debris, rather than engulfing whole RBCs. Hemolysis in the vitreous may have been initiated by the unfavorable microenvironment. Two types of vitreous membranes occurred during vitreous clot lysis. Cellular membranes were composed of aggregates of giant macrophages enclosed within a thin collagen sheet. Acellular membranes developed from coaggregated vitreous collagen fibers. A prominent acellular membrane surrounded the blood clot as a pseudocapsule. No fibroblasts or fresh collagen deposition were observed.


Intraocular penetration of subconjunctivally administered 14C-fluorouracil in rabbits.

Fluorouracil is given for a variety of neoplasms by various administrative routes. Toxicity of susceptible normal tissue limits systemic dosage, but at this level intraocular tissue may not receive tumor-inhibiting concentrations. Subconjunctival administration of 6.25 mg of 14C-fluorouracil in 0.5-mL dosages resulted in a peak anterior chamber concentration of 69.5 micrograms/mL and a peak vitreous concentration of 10.5 micrograms/mL over the 12 hours tested. This resulted in no visible ocular damage. The intraocular levels achieved were greater than the concentration reported to inhibit selected tumors. The total dosage administered was considerably below the level of systemic toxicity.


Coronal adenomas.

The incidence and morphologic features of coronal adenomas, benign epithelial tumors of the ciliary processes, were studied in 500 autopsy cases. Macroscopically, coronal adenomas are white, globular, often cystic in appearance, of limited growth potential, and found only on the ciliary processes. Microscopically, they contain convoluted sheets or tubes of nonpigmented epithelium, between which are found varying amounts of amorphous eosinophilic, PAS-positive, extracellular material. Coronal adenomas were present in 153 (31%) of 500 cases, were bilateral in 23 (15%), and were thus present in 176 (18%) of the 1,000 eyes examined. Two clinically important complications of coronal adenomas were found, sectoral cataracts and misdiagnosis as iris tumor.


The use of antibiotics in general practice.

The prescribing of antibiotics in extra-hospital practice has now reached a level of one sixth of all Australian Pharmaceutical Benefit scheme prescriptions. In the last documented year prescriptions for the penicillins alone amounted to almost eight millions. Is this wholesale prescribing of potent, expensive, and, at times, dangerous chemotherapy really justified. This article will examine the indications for overall use of antibiotics, the pitfalls of their careless prescribing, and briefly review the main indications for each group of drugs in regular use in family practice. The discussion will therefore not include some drugs which are ordinarily limited to hospital practice, nor many of the regimes used in serious or life threatening disease such as meningitis or septicaemia.


Penicillin update.

The penicillins are the safest and most commonly prescribed antibiotics in Australia, accounting for 7.8 per cent (8 million prescriptions) of all 'Pharmaceutical Benefit' prescriptions for the year 1977/78. The range of penicillins available covers a very wide spectrum of susceptible bacteria, and includes the majority of all bacterial infections seen by the general practitioner.


A shortcut to rational prescribing. Matching the bug and the drug.

The rational use of antibacterial chemotherapy in the clinical setting is a necessary objective, but a difficult task. This article presents a particular interpretation of history that links bacteria, conditions and chemotherapy in a prescribing rule that applies to much of the bacterial infection seen in clinical practice. Whilst retaining a rational basis, use of the rule simplifies day-to-day prescribing of antibacterial chemotherapy.


Medication patterns--cause for interprofessional liaison.

Two recent surveys, one by the Australian Bureau of Statistics, the other by the Victorian College of Pharmacy in conjunction with the Institute of Applied Economic and Social Research, cast light on prevailing medication patterns. These surveys, for the first time, indicate not only patterns and trends in the taking of prescribed medicines, but also in the taking of pharmacist controlled non-prescribed medicines and open selling medicines.


Antibiotics in immunosuppressed patients.

The initial treatment of an infection in an immunosuppressed patient must be aimed at the most commonly involved microorganisms which may result in a rapidly fatal infection. As soon as a microbiological diagnosis had been made, the treatment should be altered if necessary to provide optimal management of the condition.


Electrocardiography, heart scope and haematology of horses competing in an endurance ride.

Thirty-one horses competing in a 100 kilometre endurance ride had electrocardiograms recorded before and after the ride from which the heart score of each horse was calculated. Blood was also taken to determine the packed cell volume (PCV) and total plasma protein (TPP) before the ride, after 60 kilometres (mid ride) and at completion of the ride. Statistical analysis of the heart scores showed that a faster group of horses had significantly higher heart scores than either a slower group or those eliminated due to inadequate recovery of heart rate. No horses developed electrocardiogram abnormalities as a result of the ride. Analysis of the results of PCV and TPP showed that horses became dehydrated during the ride. The faster group of horses had significantly higher PCV values and heart rates at both the mid-ride and end of ride sampling times. However, the TPP values indicated no significant differences in the amount of dehydration between the 2 groups.


Reproductive performance of beef cattle in northwestern Queensland.

The reproductive performance of beef cattle in 5 herds mated all year round in north-west Queensland was examined from 1970 to 1973. Conception rates, conception patterns and branding rates were used to assess annual reproductive performance. The level of loss between the times of confirmed pregnancy and branding was defined. The mean annual conception rate was 83.1% with individual property means ranging from 75.4 to 90.9%. Conception rates for heifers, first calf cows and mature cows were 83.9%, 80.6% and 84.7% respectively. Conception patterns were influenced by seasonal conditions, 68.1% of conceptions occurring in the wet season, between December and May. In this region, conception patterns were highly correlated with rainfall during the previous month. Losses between the times of confirmed pregnancy and branding ranged from 5.9 to 27.7%. Body condition of animals varied and was dependent upon lactation, seasonal and parity effects.


The role of equipment that has direct contact with the carcase in the spread of Salmonella in a beef abattoir.

Counts of Salmonella were performed by the most probable number technique on 16 articles of abattoir equipment having direct contact with the carcase. Forty samples were collected from each article over 21 months. The contamination rate of these articles with salmonellae varied from nil % for a saw used to quarter the sides to 47.5% for stainless steel tables and hooks. Mesh gloves were also highly contaminated, salmonellae being isolated from 32.5% of gloves on the slaughter floor and 40% of those in the boning room. Salmonella counts ranged from 1.0 to 3,663 organisms per article. Mesh gloves, cutting boards and stainless steel tables were found to have counts that were at times greater than 1,000 salmonellae per article.


Treatment of ovine annual ryegrass toxicity with chlordiazepoxide.

The results of pen trials indicate that sheep affected by annual ryegrass toxicity can be treated successfully with chlordiazepoxide. In the first experiment, 87% of chlordiazepoxide-treated animals survived a lethal dose of toxic ryegrass. In the second experiment, 90% of chlordiazepoxide treated animals survived compared with a 10% recovery of control animals.


Poisoning of chickens and ducks by pyrrolizidine alkaloids of Heliotropium europaeum.

The disease produced by feeding chickens and ducks a commercial poultry feed containing heliotrine and lasiocarpine, pyrrolizidine alkaloids of Heliotropium europaeum, is described. Illthrift, ascites and degenerative lesions in the liver were the major findings. Similar lesions occurred in chickens fed a diet containing H. europaeum. The source of the alkaloids in commercial poultry feed was probably the seeds of H. europaeum harvested with wheat.


The epidemiology of equine strongylosis in southern Queensland. 2. The survival and migration of infective larvae on herbage.

The seasonal changes in longevity on herbage of the infective larvae of strongylid nematodes of the horse were studied. During the summer months, 1% of the larvae survived on herbage for 2-3 weeks, with 0.2% still viable for a further 2-3 weeks. Equivalent survival periods in winter were 7-11 weeks and over 11 weeks respectively. During spring and autumn, larvae survived for periods varying from 3-8 weeks. On Rhodes grass (Chloris gayana) growing vigorously in the summer of 1976, the majority of larvae remained in the lowest layers of the pasture, within 10 cm of the soil surface. Very few reached the highest fraction of grass sampled, above 40 cm from the soil. More larvae were recovered higher on the pasture in a period when less torrential rain had occurred. It was concluded that the parasitological benefits to be gained from short-term mixed grazing with horses and cattle may be minimal, in view of the tendency of cattle to eat only the upper layers of the pasture initially, with a consequent increase in the number of infective larvae per unit weight of herbage remaining.


The epidemiology of equine strongylosis in southern Queensland. 3. Seasonal variation in arterial populations of Strongylus vulgaris, and the prevalence of some helminths.

The anterior mesenteric arteries of 138 horses slaughtered in southern Queensland were examined for the presence of S. vulgaris larvae. Seasonal differences were noted in the size of arterial populations of this parasite, with higher mean monthly numbers of worms per horse occurring in winter. There was an equally high incidence of severe verminous arteritis during the winter months of June, July and August, compared to arteries examined during the warmer months, when there were smaller numbers of larvae. It was concluded that more infective larvae were available on pasture during the warmer months, with subsequently large arterial populations some 3 to 4 months later. The parasite was encountered in 121 arteries (88%). The prevalence of adult helminths in the caeca of the same group of horses was S. vulgaris 88%; S. equinus 70%; S. edentatus 18%; Triodontophorus spp. 23%; A. perfoliata 62%. The overall prevalence of S. vulgaris was 93%, when the results of arterial and caecal observations were combined.


The blowfly strike problem of sheep in New South Wales.

A field survey was undertaken between 1972-76 to reappraise the nature of the blowfly problem in New South Wales. For 2 years, 1972-1974, some 80,000 sheep were kept under observation and 12,481 strikes were reported, most due to Lucilia cuprina. Breech strike was still the basic problem but tail strike associated with scouring had become an important component where pastures have been improved. Breech strike was controlled at minimal cost by managerial practices such as docking tails the correct length--second joint-space palpable ventrally (midway down the vulval orifice in ewes) for radically mulesed lambs and the third joint-space (tip of vulva in ewes) for all other lambs-mulesing at lamb marking, mid-season crutching, determining the cause of scouring and applying the appropriate preventative or remedial measures. Thus the use of insecticides could be reserved for the control of body strike in young sheep in the odd wet years and poll strike in horned rams. Major outbreaks of body strike occurred in 1973/74. Body strike worried graziers most because of its unpredictability, sudden onset and scale. and only failing insecticides were available for control.


Effect of disruption of the sebaceous layer of the sheep's skin on the incidence of fleece-rot.

It was postulated that integrity of the sebaceous layer on the skin is important in maintaining resistance to fleece-rot. This hypothesis was tested in an experimenta of a 2 x 2 factorial design in which sebaceous layer disruption and wetting were the 2 treatments. The sebaceous layer was disrupted by applying a light petroleum solvent to the skin of the sheep. Fleece-rot occurred in all sheep (20) that were both wetted and had the sebaceous layer disrupted while 9/19 of those wetted but without the sebaceous layer disrupted developed fleece-rot. The fleece-rot lesions observed were more severe in sheep in the disrupted wetted treatments than in the intact wetted treatment. Interpretation of these differences was complicated by a possible reaction of the skin to the solvent used. The differences were not due to an effect of treatment on fleece wettability. No fleece-rot developed in the sheep not wetted and application of the solvent alone did not induce fleece-rot.


Tracheitis in sheep after oral administration of a mineral supplement.

Outbreaks of illness and deaths in sheep after the concurrent administration of a cobalt, copper and zinc mineral supplement and laevamisole are described. Clinical illness was characterised by profound dyspnoea and inability to exercise. The consistent postmortem finding was severe, necrotising tracheitis with partial occlusion of the airway. This lesion was reproduced experimentally by intratracheal administration of the mineral supplement dissolved in one particular formulation of laevamisole but not in water or another preparation of laevamisole. Further experiments revealed that combined zinc sulphate and copper sulphate dissolved in the particular formulation of laevamisole would produce the tracheal lesions.


Visual recognition thresholds in a compressed air environment.

An experiment was performed to determine the effects of different high-pressure air environments on human binocular visual recognition time as a function of stimulus size and type. Eight adult male volunteers were randomly exposed to high-pressure air environments in hyperbaric test chambers instrumented for visual studies. Analysis of variance for a three-factor repeated-measures design revealed significant main effects for the variables of stimulus size and pressure, indicating that recognition time (RT) increases as a function of decreasing stimulus size and increased pressure. A significant interaction was also observed between the independent variables of pressure and stimulus type with stimulus type having the greatest effect at low pressure. These results are discussed for their applicability to the design of underwater equipment, visual displays, and the occupational safety of underwater workers.


Effect of fiber and dye degradation products (FDP) on burn wound healing.

Upon exposure to the thermal environment of an aircraft fire, many fire retardant fabrics off-gas fiber and dye degradation products (FDP). Condensation of these products on human skin raises questions concerning possible deleterious effects on burn wound healing. A porcine bioassay was used to study the physiological effects of FDP. Selected areas of living skin, protected by dyed aromatic polyamides and polybenzimidazole fabrics, were exposed to a thermal source adjusted to simulate a postcrash JP-4 fuel fire. Burn sites contaminated with FDP were evaluated by clinical observation ane to begin epithelialization, time to closure of an open wound, and the amount and type of cicatrix formation. The experiment showed that each fabric has unique off-gasing products. The greatest amount of FDP was deposited on the skin when the skin was covered by a single layer of shell fabric separated by a 6.35-mm air gap. The presence of an intervening cotton T-shirt decreased the amount of FDP deposited on the skin. We found no evidence that FDP caused alterations in wound healing.


Bimodal relationship of human tremor and shivering on introduction to cold exposure.

Four subjects were exposed to an environmental challenge of -12 degrees C for 15 min in four conditions of exposure: 1) clothed body and clothed arm, 0.5 clo units: 2) clothed body and exposed arm, 0.4 col; 3) exposed body and exposed arm, 0.1 clo: 4) exposed body and clothed arm, 0.2 clo. Core temperature, surface temperature of the right arm, perceived thermal comfort, EMG indicated onset of shivering, and the frequency of tremor using accelerometry were monitored and data collected every 30 s. The results indicate that tremor frequency significantly increases with cold exposure, but that a significant drop in tremor frequency precedes the onset of shivering. It is suggested that pre-shivering tetany occurs prior to the onset of shivering, acts as a load upon the lever of the hand and reduces the oscillation of the limb.


Comparison of physiological effects of head-down tilting and immersion on the human body.

Among the methods simulating weightlessness, effects on the human body, head-down tilting and water immersion are very useful. The purpose of the present investigation was to carry out a comparative study of water balance and water-protein composition of the blood using the above two methods to simulate the physiological effects typical of an acute stage of weightlessness adaptation. The results of the 7-d head-down tilting and immersion experiments allow the following conclusions: More pronounced changes in water balance and water-protein composition of the blood during immersion seem to indicate that immersion produces a greater effect on the human body; The pattern of changes during immersion and tilting suggests that the adaptation period to immersion takes a longer time; These findings give evidence that immersion, compared with head-down tilting, reproduces more closely effects of acute adaptation to simulated weightlessness.


Bioassay of thermal protection afforded by candidate flight suit fabrics.

The United States Army Aeromedical Research Laboratory (USAARL) porcine cutaneous bioassay technique was used to determine what mitigating effect four thermally protective flight suit fabrics would have on fire-induced skin damage. The fabrics were 4.8-ox twill weave Nomex aramide, 4.5-oz stabilized twill weave polybenzimidazole, 4.8-oz plain weave experimental high-temperature polymer (HT4), and 4.8-oz plain weave Nomex aramide (New Weave Nomex or NWN). Each fabric sample was assayed 20 times in each of four configurations: as a single layer in contact with the skin; as a single layer with a 6.35 mm (0.25 in) air gap between fabric and skin; in conjuction with a cotton T-shirt with no air gaps; and, finally, in conjuction with a T-shirt with a 6.35 mm air gap between T-shirt and fabric. Bare skin was used as a control. A JP-4 fueled furnace was used as a thermal source and was adjested to deliver a mean heat flux of 3.07 cal/cm2/s. The duration of exposure was 5 s. Four hundred burn sites were graded using clinical observation and microscopic techniques. Used as single layers, none of the fabrics demonstrated superiority in providing clinically significant protection. When used with a cotton T-shirt, protection was improved. Protection improved progressively for all fabrics and configuration when an air gap was introduced. The experimental high-temperature polymer consistently demonstrated lower heat flux transmission in all configurations, but did not significantly reduce clinical burns.


Comparison of the job attitudes and interest patterns of air traffic and airway facility personnel.

Air traffic control specialists (ATCSs) and airway facility technicians (AFTs) were compared on measures of job attitudes and interests. A total of 792 ATCs and 2,366 AFTs completed the Strong Vocational Interest Blank (SVIB) and questionnaires concerning job satisfaction and job attitudes. Both groups indicated high overall job satisfaction and general agreement about areas of job satisfaction and dissatisfaction. However, ATCSs. On the SVIB, ATCSs had higher scores than AFTs on scales concerned with interpersonally oriented vocations (e. g. social service, sales) and lower scores on technical-scientific occupational scales. The findings suggest that these two employee groups have many common attitudes toward work while at the same time having certain discriminable characteristics that have implications for both personnel and motivational programs.


Similarity in the number of lifespan heartbeats among non-hibernating homeothermic animals.

An investigation was made of the available data on heart rates and maximum lifespan of a number of vertebrates from a variety of sources; only data pertinent to resting adult non-anesthesized homeothermic mammals and birds in a state of thermal neutrality were subsequently analyzed. All known hibernators were excluded because of their extreme, and largely unknown, range of heartbeat from season to season. Plots of heart rate (beats per minute) against reciprocal of lifespan in years showed surprisingly good fits (r = +0.90 for mammals and r = +0.64 for birds). Computation of the total number of heartbeats in the maximum recorded lifespans of the mammalian and avian species involved in this study showed that the mean cumulative heartbeat number for 31 mammalian species was 100 +/- 8 S.E.M. x 10(7) beats and for 23 avian species was 326 +/- 22 S.E.M. x 10(7) beats. This paper documents this analysis, which supports the concept of a close similarity in lifespan heartbeats among mammalian species and among avian species.


Cold water survival suits for aircrew.

Laboratory and sea trials were used to compare the effectiveness of three aircrew exposure garments--the British Mark 10, the United States CWU 21/P, and the Canadian U.VIC. Thermofloat jacket. The first two are waterproof coveralls, whereas the third is a neoprene-lined jacket designed on the basis of the "wet suit" concept. Rectal and skin temperatures, electrocardiograms and other variables were measured while subjects, wearing the suits, were immersed in water at temperatures of 70 degrees C and 10.5 degrees C. The three garments were found to be similar in the degree of thermal protection provided, but the Thermofloat jacket appeared superior in other ways and has the greater potential for development. A previously unreported observation was a marked reduction in core cooling rate after the expected linear fall in core temperature. This has possible implications in the conduct of research in this field.


Susceptibility to seasickness: influence of hull design and steaming direction.

Three sea going vessels steamed side by side through slight seas off the coast of Oahu, Hi. A 4-h octagon was transmitted twice each day for three consecutive days while motion sickness symptomatology was recorded from 18 enlisted men who alternated among the vessels. Dramatic differences in illness severity were obtained whether comparisons were made using objective evidence of vomiting episodes or subjective reporting of symptoms on questionnaires. Reliability of this scoring method was excellent (r = .95). In addition to face and construct validity, evidence is presented of the predictive validity of the scoring method in a separate octagonal steaming experiment using a 95 ft Coast Guard patrol boat in an equivalent experimental paradigm. This study showed significant covariance between the magnitude of motion sickness symptomatology and the encounter direction of the vessel to the primary swell (p less than 0.01). Additionally, significant correlations were found between sickness severity and test subject concentration, fatigue, urine production, and urine specific gravity. The majority of these relationships would not have been disclosed had only the dichotomous criterion of vomit/nonvomit been employed in assessing motionsickness severity. Implications of these data as design criteria for marine vehicles are discussed.


Passive resistive torques about long bone axes of major human joints.

Multisegmented total-human-body models play an important role in studies such as vehicle crash victim simulation, pilot ejection and flailing. Proper biomechanical description of the major articulating joints of these mathematical models require passive resistive torque data for the rotational motions of the body segments about their long bone axes. This paper presents a research program which was developed to collect such data at the shoulder, hip, knee, elbow, and ankle joints. The research was conducted, with some obvious limitations, on live human subjects by means of specially designed experimental apparatus. The numerical results are presented for three subjects for the passive resistive torques about the long bone axes of the major articulating joints. It was concluded that the maximum tolerable passive resistive torques associated with the long bones of the lower extremities are more than twice the ones associated with the long bones of the upper extre mities.


Medical barofunction testing of aviators with otorhinolaryngologic disease.

Forty aviators with otorhinolaryngologic pathology, previously considered physically disqualified for flight status, were tested in the hypobaric chamber to evaluate tolerance to rapid barometric pressure changes. Testing consisted of three sequential trials in the low-pressure chamber (LPC) at rates of 1,524 m, the second to 3,048 m, and the third to 5,486 m. Failure consisted of any symptoms (pain) or physical findings of barotrauma (aerosinusitis or aerootitis media). Results revealed a 22.5% failure rate. The findings indicate this type of "Medical Barofunction Test" is a practical adjunct to the clinical evaluation of the aviator. The profile is safe and free from serious dysbaric episodes experienced above 7.620 m. Follow-up studies revealed the incidence of false negatives to be only 8% by the LPC test. The findings are not significantly different from the medical disqualification rate of a normal student aviator comparison group.


Containment aircraft transit isolator.

The Containment Aircraft Transit Isolator is a self-contained unit capable of transporting a patient with a highly virulent disease and at the same time providing maximum microbiological security while full nursing care and treatment are carried out. The isolator was employed in a trans-Atlantic simulated aeromedical evacuation in a Canadian Forces Boeing 707. During the exercise, flight testing was undertaken and nursing care, treatment, and decontamination procedures were developed and evaluated. Flight medical personnel were trained in the use of the unit. It was concluded that flight-trained medical teams, well versed in general aviation medicine and with a detailed familiarity with the isolator, are necessary for safely transporting patients with exotic diseases.


Coping with expanding nursing practice, knowledge, and technology.

Nurses utilize transcultural, transactional, systems, primary, and interdisciplinary approaches to physiological and psychosocial components of patient care. Expanded roles, as well as advances in knowledge and technology have prepared nurses for critical, specialized, primary, aerospace, and independent nursing practice. Exciting as they are, nursing's expanded roles and practices frequently contribute to the burnout and distress phenomena increasingly observed in practicing health care professionals. Causes and symptoms of the burnout distress phenomena are many and varied. Selye, Shubin, Maslach, and others adeptly identified and wrote on the phenomena as it specifically relates to nurses and the many facets of nursing practice. Rather than utilizing crisis intervention coping techniques, preventive strategies and adaptations are suggested. This paper reviews and discusses: 1. Factors associated with burnout-distress phenomena identified in professional literature; 2. Identification of factors associated with expanded roles and practice which contribute to burnout stress; 3. Identification of factors in military and civilian air ambulance and aeromedical evacuation systems which contribute to burnout stress; 4. Recommendations for strategies to prevent and cope with burnout distress factors.


Technique for simulating G-induced tunnel vision.

A simple technique is described which helps subjects gain an understanding of the endpoint used to terminate exposure to centrifuge stress during training procedures on the human centrifuge. The technique involves manual induction of increased intraocular pressure which, in turn, causes a decrease in retinal perfusion followed by greyout and tunnel vision.


Pilot performance during simulated approaches and landings made with various computer-generated visual glidepath indicators.

Two simulator experiments were conducted to quantify the effectiveness, in terms of pilot performance, of four different visual glidepath indicator systems (the 2-bar VASI, 3-bar VASI, T-VASIS, and PAPI) in the severely reduced nighttime visual environment often referred to as the "black hole." Performance in Experiment I was best with the T-VASIS and decreased with the 3-bar BASI, PAPI, and 2-bar VASI, in that order; but differences between the T-VASIS, 3-bar VASI, and Papi were not statistically significant. Approaches flown withou the ground-vased glidepath indicators tended to be low and extremely variable. Observing behavior was compared in approaches with the T-VASIS and 2-bar VASI. Observing response frequency increased as distance from runway threshold decreased and was significantly higher with the T-VASIS. Differences in performanange provided by a given system and to the rate of observing the indicator during approaches.


Inbreeding and heterogamic mating: an alternative to Averhoff and Richardson.

An alternative explanation to the pheromonal control of mating through chemoreceptor saturation proposed by Averhoff and Richardson (1974) is offered for the apparent rise in heterogamic mating in their experiments, after several generations of full-sib mating. In a multiple-choice mating between two genotypic strains differing in their level of sexual vigor, there is a sequence from heterogamic to homogamic mating. It is proposed that, by reducing mating speed, inbreeding changes the rate of this sequence but not its pattern, so the apparent level of heterogamic mating will increase during inbreeding, for a fixed observation period. This hypothesis was tested using the Kence-Bryant model of mating success.


Behavior in chimeric mice combining differently behaving strains.

A/J and C57BL/6J mice behave differently in tests for alcohol preference, open-field activity, defecation in the open field, cricket attacking, and rope climbing. Chimeric mice, i.e., mice containing both A/J cells and C57BL/6J cells, were constructed and tested for these behaviors. Patterns of behavior among A/J in equilibrium with C57BL/6J chimeras are such as to suggest that none of these behavior differences is controlled by a single cell or clone and that the same cell population that gives rise to the strain difference in alcohol preference also gives rise to the differences in open-field activity and defecation, while separate cell populations control cricket killing and rope climbing.


Sex effect on the risk of mental retardation.

Risks of mental retardation were computed separately for the relatives of male and female probands. When compared, the risks for the relatives of females were always significantly higher than the risks for the relatives of males. These findings are consistent with the hypothesis of a differential genetic loading for males and females.


Genetic selection for avoidance behavior in the rat.

Long-Evans rats were selectively bred for over 20 generations using two behavioral criteria: (1) limited responding to the warning signal during ten pretest trials and (2) either good or poor avoidance behavior during 60 avoidance training trials in a two-way shuttlebox. The results suggest that avoidance behavior in the rat is a heritable characteristic that may be selected independently of activity level.


Phenotypic vs. genotypic sex and cognitive abilities.

As a test of whether sex differences in cognitive functioning are determined by chromosomal constitution or hormonal events, eight subjects whose phenotypic sex differed from their genotypic sex were given a standard intelligence test. The results indicated that differences between verbal and nonverbal abilities corresponded to phenotypic rather than genotypic sex. The roles of environmental factors, sex steroid hormones and alternate genetic mechanisms in determining intellectual dimorphisms are examined.


Probabilistic theories of coalition formation in groups.

Chertkoff's (1967) and Walker's (1973) theories of coalition formation for decision making, which attempt to predict the probabilities of the occurrence of coalitions in three-person group systems, are extended to apply to certain situations involving groups larger than these triads. These two extended theories and Komorita's (1974) weighted probability theory, which attempts to predict the probabilities of occurrence of coalitions in groups of any size, are compared according to how well they can account for the results of a number of previously reported experiments, both on triads and on larger groups. In general, this comparison shows that: (a) Chertkoff's theory cannot account for the results; (b) Walker's theory can account only for the results of experiments in which all the minimal winning coalitions are equal in size; and (c) Komorita's theory can account only for the results of experiments in which there is some difference in size among the minimal winning coalitions. It is suggested that the theories of Chertkoff and Walker do not attribute enough importance to size as a factor in coalition formation, while weighted probability theory attributes too much importance to this factor.


An equal excess model of coalition formation.

Current theories of coalition formation in decision processes of systems at the level of the group lack generality in that some theories do not predict which coalitions are likely to form while others make predictions in only a narrow range of conditions. A model of coalition formation is proposed which predicts coalition formation in a variety of situations. Comparisons between predicted and observed results of studies using different coalition paradigms show considerable empirical support for the model. Despite some ambiguity in specifying the effects of some situational variables, the model provides a framework with which to study the processes of coalition formation and to examine the effects of such situational factors.


Free sugar fraction of the amylose-related mutants of maize.

The free sugar fraction of normal and amylose-related mutants of maize has been studied. The mutant waxy, characterized by a starch deprived of amylose, does not differ from the normal maize so far as free sugars are concerned. We report, however, the presence of maltose in waxy extracts, a disaccharide otherwise supposed to be absent in this genotype. Three high-amylose mutants (amylose extender, dull, and sugary-2) can be differentiated on the basis of the content of free sugars: dull and sugary-2 enhance amylose synthesis without inducing the presence of starch amylolytic products, while amylose extender accumulates a large quantity of maltose and maltooligosaccharides with a degree of polymerization between 3 and 8. In developing endosperm of amylose extender an abnormal amylolytic activity may be responsible for the observed abnormalities in free sugars and starch characteristics.


Genetics and ontogeny of alcohol dehydrogenase isozymes in the mouse: evidence for a cis-acting regulator gene (Adt-i) controlling C2 isozyme expression in reproductive tissues and close linkage of Adh-3 and Adt-i on chromosome 3.

An electrophoretic variant previously reported for the stomach isozyme of alcohol dehydrogenase (ADH-C2) in inbred strains of Mus musculus (Holmes, 1977) has been used to localize the gene encoding this enzyme (Adh-3) on chromosome 3 near Va (varitint) (9.6 +/- 3.6% recombinants). Genetic variation of ADH-C2 activity in male and female reproductive tissues among inbred strains and Harwell linkage testing stocks was also observed. Reproductive tissue ADH-C2 phenotypes were inherited in a normal Mendelian fashion among F2 progeny of an F1 (LII x C57BL/Go) x C57BL/Go backcross as though controlled by a single cis-acting regulator locus (designated Adt-1) with two alleles: Adt-1a (presence of ADH-C2) and Adt-1b (absence or low activity of ADH-C2). No recombinants were observed among 73 progeny or among 13 inbred strains and six Harwell linkage testing stocks of mice, indicating that Adh-3 and Adt-1 are closely linked or identical genes. A single recombinant phenotype was observed in Peru-Coppock mice, suggesting that they are separate genes. Ontogenetic analyses demonstrated that ADH-B2 is present throughout development from late fetal stages in stomach, liver, and kidney; similar results were found for ADH-C2 in developing kidney and stomach extracts, whereas ADH-A2 exhibited high activity in liver extracts after 3 weeks of age in both sexes and in male kidney extracts after 6 weeks.


Genetics, ontogeny, and testosterone inducibility of aldehyde oxidase isozymes in the mouse: evidence for two genetic loci (Aox-I and Aox-2) closely linked on chromosome 1.

"Null"-activity and low-activity variants for the liver supernatant isozymes of aldehyde oxidase (designated AOX-1 and AOX-2) were observed in inbred strains and in Harwell linkage testing stocks of Mus musculus. The genetic loci determining the activity of these isozymes (designated Aox-1 and Aox-2, respecitively) are closely linked on chromosome 1 near Id-1 (encoding the soluble isozyme of isocitrate dehydrogenase). Linkage data of Aox-1 with Id-1 and Dip-1 (encoding a kidney peptidase) demonstrated that this gene coincides with or is closely linked to Aox (Watson et al., 1972). Ontogenetic analyses demonstrated that liver AOX-1 appeared just before birth and increased in activity during postnatal development, whereas liver AOX-2 was observed only during postnatal development. Adult male livers exhibited higher AOX-1 and AOX-2 activities than adult female livers. Both isozymes were significantly reduced in activity by castration of adult males and increased following testosterone administration to castrated males and normal female mice.


Assignment of histidase-regulating locus to chromosome 10 of the mouse.

Data from four sets of recombinant inbred strains confirm that variation at a single genetic locus is responsible for the previously observed differences in the rate of histidase synthesis in inbred mice. Linkage testing stocks were used to demonstrate linkage with steel (Sl) on chromosome 10.


Genetic analysis of alcohol dehydrogenase isozymes in pearl millet (Pennisetum typhoides).

Pearl millet (Pennisetum typhoides) produces three ADH isozymes, sets I, II, and III, with set III being expressed only in anaerobically treated seeds of seedlings. Variant strains have been identified which produce ADH isozymes with altered electrophoretic mobilities for sets I and II but not for set III activity. Based on genetic analysis of these variants and on dissociation-reassociation experiments, we propose that the three ADH isozymes are dimers of subunits coded by two structural genes, Adh1 and Adh2, with set I being a homodimer specified by Adh1, set III a homodimer specified by Adh2, and set II a heterodimer formed between the products of Adh1 and Adh2.


Drosophila alcohol dehydrogenase activity in vitro and in vivo: effects of acetone feeding.

When adult Drosophila are placed on medium containing 0.5% acetone, their level of alcohol dehydrogenase activity drops rapidly. At the same time, the proportion of activity in the various electrophoretic forms of the enzyme shifts; most of the activity becomes localized in what is ordinarily a minor form of the enzyme. Moreover, the loss of enzyme activity occurs in vivo as well, as shown by sensitivity to ethanol poisoning, insensitivity to pentenol treatment, and inability to utilize ethanol as an energy source. These observations are discussed in light of a model advanced for the origin of the multiple forms of alcohol dehydrogenase in Drosophila.


Multiplicity of molecules carrying blood-group-I antigen on erythrocyte membranes.

A human serum containing a monoclonal anti-(blood-group I) antibody was used to investigate the distribution of blood-group-I antigen on erythrocyte membrane components. Sodium dodecyl sulphate/polyacrylamide-gel-electrophoresis profiles of immuneprecipitates by using 3H-labelled (by the galactose oxidase/NaB3H4 method) and 125I-labelled solubilized stroma were compared. Different radioactive profiles were revealed by the two radiolabelling methods. In the immunoprecipitates the predominant 125I radioactivity within the gel had the electrophoretic mobility of Band-3 protein (apparent mol.wt. 90 000--100 000), whereas the 3H radioactivity revealed a diffusely migrating component(s) (apparent mol.wt. range 40 000--70 000) in addition to radioactivity compatible with glycolipids at the dye front. The diffusely migrating 3H-labelled component was shown to have a similar electrophoretic mobility to a subpopulation of erythrocyte poly(glycosyl)ceramides with blood-group-I activity.


Interaction of di-iodinated 125I-labelled alpha-bungarotoxin and reversible cholinergic ligands with intact synaptic acetylcholine receptors on isolated skeletal-muscle fibres from the rat.

1. Intact synaptic acetylcholine receptors on freshly isolated rat skeletal-muscle fibres were characterized by their interaction with di-iodinated 125I-labelled alpha-bungarotoxin, acetylcholine and other cholinergic ligands at room temperature (22 deggrees C). 2. The time course and concentration dependence of 125I-labelled alpha-bungarotoxin association conformed to a bimolecular mechanism. In time-course experiments with different concentrations of 125I-labelled alpha-bungarotoxin (1.4--200 nM) the bimolecular-association rate constant, k + 1, was (2.27 +/- 0.49) x 10(4)M-1.S-1 (mean +/- S.D., N = 10). In concentration-dependence experiments, k + 1 was 2.10 x 10(4)M-1.S-1 and 1.74 x 10(4) M-1.S-1 with 10 and 135 min incubations respectively. In association experiments the first-order rate constant was proportional to the 125I-labelled alpha-bungarotoxin concentration. 125I-Labelled alpha-bungarotoxin dissociation was first order with a dissociation constant, k-1, less than or equal to 3 x 10(-6)S(-1) (half-life greater than or equal to 60 h.) The results indicated a single class of high-affinity toxin-binding sites at the end-plate with an equilibrium dissociation constant, Kd, equal to or less than 100 pM. The number of toxin-binding sites was (3.62 +/- 0.46) x 10(7) (mean +/- S.D., n = 22) per rat end-plate. 3. The apparent inhibitor dissociation constants, Ki, for reversible cholinergic ligands were determined by studying their effect at equilibrium on the rate of 125I-labelled alpha-bungarotoxin binding. There was heterogeneity of binding sites for cholinergic ligands, which were independent and non-interacting with antagonists. In contrast agonist affinity decreased with increasing receptor occupancy. Cholinergic ligands in excess inhibited over 90% of 125I-labelled alpha-bungarotoxin binding. 4. Cholinergic ligand binding was accompanied by an increase in entropy, which was greater for the agonist carbachol (delta So = +0.46 kJ.mol-1.K-1) than the antagonist tubocurarine (delta So = +0.26 kJ.mol-1.K-1). 5. The entropy and affinity changes that accompanied agonist binding suggested that agonists induced significant conformational changes in intact acetylcholine receptors. 6. The affinity and specificity of 125I-labelled alpha-bungarotoxin and tubocurarine binding to synaptic acetylcholine receptors from slow and fast muscle fibres were the same. 7. The study of binding only requires milligram amounts of tissue and may have application to other neurobiological studies and to the study of human neuromuscular disorders.


Characterization of an oxygen-stable nitrogenase complex isolated from Azotobacter chroococcum.

In crude cell-free extracts of Azotobacter chroococcum, nitrogenase was much less sensitive to irreversible inactivation by O2 than was the purified enzyme. When nitrogenase was partially purified by anaerobic discontinuous sucrose-density-gradient centrifugation, O2-tolerance was retained. This preparation was considerably enriched in four polypeptides, three of which were derived from the Mo-Fe(molybdenum-iron) protein and Fe (iron) protein of nitrogenase. The fourth was purified to homogeneity and shown to be an iron-sulphur protein (mol.wt. 14000) probably containing a 2Fe--2S centre. When this protein was added to purified nitrogenase, the enzyme was rendered O2-tolerant, through stabilization was Mg2+-dependent. The isolated O2-tolerant nitrogenase was an equimolar stoicheiometric complex between the MO--Fe, Fe and protective proteins. It is likely that the formation of this complex in vivo is the mechanism of 'conformational protection' in this organism.


Studies on the high-mobility-group non-histone proteins from hen oviduct.

Nuclear high-mobility-group (HMG) proteins were isolated from hen oviduct. These were proteins HMG-1, -2, -3, -14 and -17, which are equivalent to the classification of calf thymus HMG proteins. Hen oviduct proteins HMG-1 and -2 were individually isolated by HCIO4.extraction and CM-Sephadex chromatographic separation. Their mol.wts. were determined as 28 000 and 27 000, respectively. The proteins have a high content of acidic and basic amino acids. The association of proteins HMG-1 and -2 with the genome of hen oviduct nuclei was probed by a limited digestion with nucleases. Hen oviduct nuclei were incubated with deoxyribonuclease I or micrococcal nuclease until 10% of the DNA was digested. The nuclear suspension was centrifuged and the contents of proteins HMG-1 and -2 in the supernatant and sediment fractions were analysed by polyacrylamide-gel electrophoresis. HMG proteins were found to be preferentially released by micrococcal-nuclease digestion rather than by deoxyribonuclease I.


Structural studies on the major component of Gladiolus style mucilage, an arabinogalactan-protein.

The major component of the Gladiolus style mucilage was shown to be an arabinogalactan-protein. The arabinogalactan-protein was isolated from the style extract by affinity chromatography with tridacnin (the galactose-binding lectin from the clam Tridacna maxima) coupled to Sepharose 4B. The isolated arabinogalactan-protein represents 40% of the soluble style extract; it contains 90% (w/w) carbohydrate and 3% protein. The major monosaccharides of the carbohydrate component are galactose and arabinose, in the proportions 6:1. A component with a similar composition was also isolated from the crude extract by precipitation with the beta-glucosyl artifical carbohydrate antigen. The protein moiety of the arabinogalactan-protein remained associated with the carbohydrate after chromatography in urea, and has high contents of serine, glutamic acid, aspartic acid, glycine and alanine. The arabinogalactan-protein is apparently chemically homogeneous; it eluted as a single symmetrical peak from Sepharose 4B, and three fractions collected across the peak were structurally similar. Ultracentrifugal studies showed it to be polydisperse in the mol.wt. range 150 000--400 000. The information obtained from methylation analyses, oxalic acid and enzymic hydrolyses is consistent with a model having a beta 1 leads to 3 galactan backbone, branched through C(O)6 to beta 1 leads to 6 galactan side chains. The arabinose is exclusively present as terminal alpha-L-arabinofuranosyl residues. Enzymic removal of the arabinose residues resulted in a marked decrease in solubility of the molecule. The localization of the arabinogalactan-protein in the mucilage of the style canal was demonstrated cytochemically. The possible roles of the arabinogalactan-protein in relation to recognition of compatible pollen and pollen-tube growth are discussed.


Bi-and tri-antennary human transferrin glycopeptides and their affinities for the hepatic lectin specific for asialo-glycoproteins.

Glycopeptides were isolated from a proteolytic digest of human transferrin. After mild acid hydrolysis the desialylated glycopeptides were labelled by the galactose oxidase/NaB(3)H(4) procedure and then fractionated by Sephadex-gel filtration or by anion-exchange chromatography. Either technique allowed separation of the two heterosaccharide chains (designated glycan I and glycan II) previously described for this protein by Spik, Vandersyppe, Fournet, Bayard, Charet, Bouquelet, Strecker & Montreuil (1974) (in Actes du Colloque Internationale No. 221 vol. 1, pp. 483-499). Subsequent chromatography on Sepharose-concanavalin A separated fractions containing different quantities of carbohydrates for each glycan, as indicated by analyses. The isolated glycan fractions were then tested for their abilities to bind to the immobilized rabbit hepatic lectin. Our studies suggest that either glycan can have a bi- or tri-antennary structure. Desialylated biantennary glycans I and II did not bind to the hepatic lectin. Desialylated triantennary glycan I was slightly retarded by the hepatic lectin, whereas the triantennary glycan II consisted of equal quantities of a retarded and a bound type. Desialylated triantennary glycan II was totally displaced from the hepatic lectin by using a buffer containing 0.05m-EDTA. The results suggest that greater structural heterogeneity exists in the carbohydrate moiety of human transferrin than was previously envisaged. Such heterogeneity could be reflected in several molecular forms of human transferrin, which, after desialylation, differ significantly in their affinities for the hepatic lectin.


The isolation and partial sequence of peptides produced by cyanogen bromide cleavage of calf thymus non-histone chromosomal high-mobility-group protein 2. Sequence homology with non-histone chromosomal high-mobility-group protein 1.

Peptides produced by CNBr cleavage of non-histone chromosomal protein HMG 2 (CNBr peptides) were isolated and characterized, and their partial sequences were determined. The present sequence data account for over half of the sequence of the protein HMG (high-mobility-group) 2 molecule, and, together with previously published results, provide interesting information on the charge distribution within the molecule. Comparison of the CNBr-peptide-sequence data for protein HMG 2 with the previously published data on the CNBr peptides from protein HMG 1 reveals extensive sequence homology between the two proteins. Detailed evidence for the amino acid-sequence data has been deposited as Supplementary Publication SUP 50095 (6 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1978) 169, 5.


Biochemical characterization of guanidinium chloride-soluble dentine collagen from lathyritic-rat incisors.

alpha- and beta-Chains were isolated by sequential ion-exchange and gel-filtration chromatography of guanidinium chloride-soluble dentine collagen obtained from Tris/NaCl-extracted EDTA-demineralized lathyritic-rat incisors. The alpha-chains were identified as alpha 1 I and alpha 2 by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and amino acid analysis of the intact chains and their CNBr peptides. The dentine alpha-chains exhibited higher lysine hydroxylation and phosphate content, but lower hydroxylysine glycosylation, than alpha-chains from skin. Increased lysine hydroxylation was observed in the helical sequences. The alpha 1 I/alpha 2 ratio was approx. 3:1, and was presumably due to the presence of (alpha 1 I)3 molecules along with (alpha 1 I)2 alpha 2 molecules as shown recently for neutral-salt-soluble dentine collagen [Wohllebe & Carmichael (1978) Eur. J. Biochem. 92, 183--188]. In the borohydride-reduced beta 11- and beta 12-chains from guanidinium chloride-soluble dentine collagen, the reduced cross-links hydroxylysinohydroxynorleucine and hydroxylysinonorleucine were present. A higher proportion of hydroxylysinonorleucine in the reduced beta 12-chain probably reflects differences in extent of hydroxylation of specific lysine residues of the alpha 1 I- and alpha 2-chains.


Multiple forms of 2-deoxy-D-glucoside-2-sulphamate sulphohydrolase from human placenta.

2-Deoxyglucoside-2-sulphamate sulphohydrolase was purified about 10 000-fold from the soluble extract of human placenta by using as substrate [N-sulpho-35S]heparin. Differently charged enzyme forms were observed on chromatography on DEAE-cellulose, all of which had an apparent mol.wt. of 110 000 as determined by gel filtration. By using immobilized heparan sulphate as affinity matrix the sulphamate sulphohydrolase could be separated into two forms, a minor one with low and a major one with high affinity for the adsorbent. When tested with [N-sulpho-35S]heparan sulphate the low-affinity form had a Km of 0.2 mM, and the high-affinity form a Km of 0.03 mM. Both forms exhibited the same Km of 10 microM towards [N-sulpho-35S]heparin and were equally well adsorbed to immobilized heparin. The two forms could be distinguished by their pH-optima and by the influence of KCl on heparan sulphate sulphohydrolase activity.


Subcellular distribution of delta 5-3 beta-hydroxy steroid dehydrogenase in the granulosa cells of the domestic fowl (Gallus domesticus).

1. The distribution of 3 beta-hydroxy steroid dehydrogenase was examined in the subcellular fractions of granulosa cells collected from the ovary of the domestic fowl. 2. 3 beta-hydroxy steroid dehydrogenase activity was observed in the mitochondrial (4000g for 20min) and microsomal (105 000g for 120min) fractions. 3. Approximately three times more 3 beta-hydroxy steroid dehydrogenase activity was associated with the cytochrome oxidase activity (a mitochondrial marker enzyme) in anteovulatory-follicle granulosa cells than with that of the postovulatory follicle. 4. Comparison of the latent properties of mitochondrial 3 beta-hydroxy steroid dehydrogenase with those of cytochrome oxidase and isocitrate dehydrogenase indicated that 3 beta-hydroxy steroid dehydrogenase is located extramitochondrially. 5. This apparent distribution of 3 beta-hydroxy steroid dehydrogenase is explained on the basis that the mitochondrial activity is either an artefact caused by a redistribution in the subcellular location of the enzyme, occurring during homogenization, or by the existence of a functionally heterogeneous endoplasmic reticulum that yields particles of widely differing sedimentation properties.


Identification of two lithocholic acid-binding proteins. Separation of ligandin from glutathione S-transferase B.

1. Two lithocholic acid-binding proteins in rat liver cytosol, previously shown to have glutathione S-transferase activity, were resolved by CM-Sephadex chromatography. 2. Phenobarbitone administration resulted in induction of both binding proteins. 3. The two proteins had distinct subunit compositions indicating that they are dimers with mol.wts. 44 000 and 47 000. 4. The two lithocholic acid-binding proteins were identified by comparing their elution volumes from CM-Sephadex with those of purified ligandin and glutathione S-transferase B prepared by published procedures. Ligandin and glutathione S-transferase B were eluted separately, as single peaks of enzyme activity, at volumes equivalent to the two lithocholic acid-binding proteins. 5. Peptide 'mapping' revealed structural differences between the two proteins.


The binding of ferric iron by ferritin.

Equilibrium-dialysis experiments with 59Fe-labelled Fe(III) chelate solutions show that ferritin is capable of binding a limited number of Fe(III) atoms. Some of this Fe(III) is readily removed, but up to about 200 Fe(III) atoms/molecule remain bound after extensive washing. Some exchange of labelled Fe(III) with endogenous unlabelled ferritin Fe occurs during prolonged dialysis against 59Fe(III)-citrate, but there is a net binding of Fe(III). Bound Fe(III) resembles endogenous Fe(III) in several respects. It appears to be attached to the micelle and not to the protein component of ferritin. Although the physiological mechanism of Fe incorporation into ferritin is unknown, our experiments suggest the possibility that some iron finds its way into ferritin as Fe(III) chelate.


An interaction between lysozyme and mucus glycoproteins. Implications for density-gradient separations.

1. Some mucus glycoproteins form soluble complexes with lysozyme at neutral pH values. 2. The extent of complex-formation was determined, by an ultracentrifugal difference method, for a range of glycoproteins covering the common blood-group specificities. 3. Interaction was strongest with those glycoproteins of blood-group Lea specificity; these were also richest in sialic acid. 4. Interaction diminished with increase of ionic strength, and was not detectable at I 0.50; however, an asialoglycoprotein was found to retain some activity. The interaction is accordingly primarily, but probably not exclusively, coulombic in origin. 5. The buoyant density of lysozyme in CsCl, CsBr, CsI and Cs2SO4 was determined; the values in the last three salts are anomalously high. This finding accounts for the previously noted difficulty of separating free protein from glycoproteins by single-stage centrifugation in CsBr. 6. Conditions for effective separation of glycoproteins from secretions containing lysozyme by density-gradient centrifugation are reported.


The role of disulphide bonds in human intestinal mucin.

Goblet-cell mucin (mucin 1) was isolated and purified from human small-intestinal scrapings. After application of mucin 1 to DEAE-Bio-Gel (A) columns, most of the glycoprotein (76-94% of hexoses) was eluted in the first peak (designated mucin 2). Minor amounts of acidic glycoproteins were eluted with 0.2m- and 0.4m-NaCl in later peaks. Analyses of mucin 1 and mucin 2 revealed mucin 2 to be a monodisperse highly glycosylated glycoprotein containing 6.3% by wt. of protein, N-acetylgalactosamine, N-acetylglucosamine, galactose and fucose. Mucin 1 was similar in composition, but was polydisperse and contained more protein (12.3% by wt.) as well as N-acetylneuraminic acid. Analytical CsCl-gradient ultracentrifugation showed both mucin 1 and mucin 2 to have a major component with an average buoyant density of 1.47000g/ml. Mucin 1 also contained a slightly less-dense minor glycoprotein component. After exhaustive reduction and alkylation mucin 1 retained its major component, but partly dissociated into two lighter glycoprotein components. Mucin 2, in contrast, did not change its density distribution after reduction. Band ultracentrifugation in (2)H(2)O-containing iso-osmotic buffers showed that mucin 1 contained a major fast-sedimenting component (s(o)=37+/-2S), and a minor amount of a slower-sedimenting component. After reduction there was an increased quantity of the latter component, for which an s(o) value of 14.5S was calculated. In contrast, mucin 2 was unaltered by reduction (s(o)=33+/-2S). These findings indicate that the major component of goblet-cell mucin (mucin 2) does not dissociate after S-S-bond reduction, and thus does not apparently rely for its polymeric structure on the association of subunits through covalent disulphide bonds. However, the effects of reduction on mucin 1 suggest that in the native mucin intramolecular disulphide bonds in the minor glycoproteins may stabilize their structure, permitting secondary non-covalent interactions to develop with the major dense mucin (mucin 2) protein.


Studies on the intracellular segregation of polyribosome-associated messenger ribonucleic acid species in the lactating guinea-pig mammary gland.

1. Free and membrane-bound polyribosomes were isolated and the associated mRNA species characterized by cell-free protein synthesis, RNA-complexity analysis and polyribosome run-off in vitro. 2. Of the recovered polyribosomal RNA 85% was associated with membrane-bound polyribosomes and contained 87--93% of the total milk-protein mRNA species as assessed by cell-free protein synthesis or RNA-complexity analysis. 3. RNA-complexity analysis showed that the abundant (milk-protein mRNA assumed) species constituted 55% of the post-nuclear poly(A)-containing RNA population, the remainder consisting of a moderately abundant population (18%) and a low abundance population (27%). Calculations suggest that each population contained up to 2, 48 and 5000 different species respectively. 4. RNA-complexity analysis of the free polyribosomal poly(A)-containing RNA demonstrated that all the species in the post-nuclear fraction were present, though in different proportions, the abundant, moderately abundant and low-abundance groups representing 38, 30 and 32% of this population. 5. RNA-complexity analysis of the membrane-bound polyribosomal poly(A)-containing RNA revealed a more limited population, 72% consisting of the abundant (milk-protein mRNA) species, and 28% a population of up to 900 RNA species. 6. Polyribosome run-off confirmed that milk-protein mRNA was associated with the membrane-bound and free polyribosomes, but represented only a small fraction of the total protein synthesized by the latter. 7. Comparative analysis of milk proteins synthesized in mRNA-directed cell-free systems, or by run-off of free and of membrane-bound polyribosomes, is consistent with the interpretation that in vivo the initiation of protein synthesis occurs on free polyribosomes, followed by the attachment of a limited population to the endoplasmic reticulum. After attachment, but before completion of peptide synthesis, the detachable N-terminal peptide sequence of one of these(pre-alpha-lactalbumin) is removed. 8. The results are discussed in terms of the mechanisms involved in the intracellular segregation of mRNA species in the lactating guinea-pig mammary gland.


The oxidation-reduction potentials of cytochrome o + c4 and cytochrome o purified from Azotobacter vinelandii.

Oxidation-reduction titrations of Azotobacter vinelandii cytochrome o + c4 and cytochrome o were performed with simultaneous potential and absorbance measurements under anaerobic conditions. Cytochrome c4 has a midpoint potential (Em, 7.4) of 260mV and purified cytochrome o has an Em, 7.4 of -18mV. Little change in the midpoint potential of cytochrome o was observed when titrated in the pH range 6.2--9.8.


Delineation of fucosyltransferase activities with thiol reagents.

The thiol reagent dithiothreitol inhibits the activity of a core GDP-fucose-N-acetylglucosaminide alpha-6-fucosyltransferase in plasma and blood-cell homogenates, while promoting the activity of alpha-2- and alpha-3-fucosyltransferases. The latter enzymes catalyse transfer of fucose on to terminal galactose and subterminal N-acetylglucosamine residues respectively. A thiol-blocking reagent N-ethylmaleimide does not affect the activity of the alpha-6-fucosyltransferase, but inhibits the other two enzymes. These results indicate the presence of a critical disulphide linkage in the alpha-6-fucosyltransferase, and provide a means of delineation of different fucosyltransferases.


The equilibrium assumption is valid for the kinetic treatment of most time-dependent protein-modification reactions.

To facilitate mechanistic interpretation of the kinetics of time-dependent inhibition of enzymes and of similar protein modification reactions, it is important to know when the equilibrium assumption may be applied to the model: formula: (see text). The conventional criterion of quasi-equilibrium, k + 2 less than k-1, is not always easy to assess, particularly when k + 2 cannot be separately determined. It is demonstrated that the condition k + 2 less than k-1 is necessarily true, however, when the value of the apparent second-order rate constant for the modification reaction is much smaller than the value of k + 1. Since k + 1 is commonly at least 10(7)M-1.S-1 for substrates, it is probable that the equilibrium assumption may be properly applied to most irreversible inhibitions and modification reactions.


Photoactivated covalent binding of [3H]bilirubin to human serum albumin.

A one-step procedure has been developed for the preparation of [3H]bilirubin IX-alpha in good yield from unlabelled bilirubin. Irradiation of an aqueous solution of [3H]bilirubin IX-alpha in the presence of human serum albumin results in the covalent attachment of the bilirubin to the protein. Preliminary degradation studies have been carried out to locate the site of attachment of the bilirubin to the albumin.


Early stimulation of rat liver microsomal protein synthesis after tri-iodothyronine injection in vivo.

In an effort to determine the physiological significance of previous studies showing stimulation of microsomal protein synthesis by thyroxine added in vitro, an early effect of tri-iodothyronine injected in vivo was sought. Tri-iodothyronine (25 micrograms/100 g) administered to euthyroid rats stimulated microsomal protein synthesis in vitro within 3--6 h. This effect occurred much earlier than the 26 h lag previously reported after tri-iodothyronine administration to hypothyroid rats. This early effect of tri-iodothyronine on protein synthesis is prevented by alpha-amanitin, suggesting that it is dependent on RNA synthesis. The failure to find a direct effect in vivo of tri-iodothyronine on translation casts doubt on the physiological significance of previous studies that have shown a direct stimulation of translation by thyroxine added in vitro.


Incorporation of N-fluoroacetyl-D-glucosamine into hyaluronate by rabbit tracheal explants in organ culture.

1. Incubation of rabbit tracheal explants with N-[(3)H]acetyl-d-glucosamine and N-acetyl-d-[1-(14)C]glucosamine led to labelling of a number of soluble macromolecular products separable from the medium, after papain digestion, by ion-exchange chromatography. 2. With N-acetyl-d-[1-(14)C]glucosamine in the incubation medium, a neutral glycoprotein, two acidic glycoprotein fractions, hyaluronic acid and a glycosaminoglycan fraction were obtained and all were radioactively labelled. Similar labelling occurred with N-fluoroacetyl-d-[1-(14)C]glucosamine or N-fluoro[(3)H]acetylglucosamine as precursor. 3. Maximal labelling was obtained at 96h after incubation of cultures. N-Fluoroacetyl-glucosamine under these conditions was incorporated into hyaluronate less efficiently than N-acetylglucosamine. 4. With N-fluoroacetyl-d-[1-(14)C]glucosamine as precursor, a hyaluronate component was separated that on enzymic degradation by glycosidases (hyaluronidase, beta-glucuronidase and N-acetyl-beta-hexosaminidase) yielded a (14)C-labelled oligosaccharide fraction together with N-acetyl-d-[1-(14)C]glucosamine and N-fluoroacetyl-d-[1-(14)C]glucosamine, consistent with some exchange of N-acetyl groups having occurred. 5. The results on enzymic degradation of labelled macromolecules by glycosidases suggest that the presence of incorporated N-fluoroacetyl side chains may render the hyaluronate analogue more resistant to hyaluronidase.


Incorporation of exogenous precursors into uridine nucleotides and ribonucleic acid. Nucleotide compartmentation in the renal cortex in vivo.

The possibility of compartmentation of UTP in vivo was investigated in the renal cortex of unanaesthetized rats. In addition, liver and spleen were studied in order to compare tissues with different utilization of precursors for pyrimidine nucleotide synthesis. After continuous 2h infusions of [(3)H]uridine or [(3)H]orotate, their incorporation into UTP, UDP-sugars and RNA was quantified. Rates of RNA synthesis were calculated by dividing the incorporation of precursor into RNA by the average specific radioactivity of the UTP pool. Although similar RNA-synthesis rates might have been expected with the two precursors, higher rates were found with uridine than with orotate. The relative incorporation into UDP-sugars of these precursors was also different. Similar results were obtained in the liver. In the spleen, equal amounts of both precursors were incorporated into UTP, but [(3)H]orotate incorporation did not lead to labelling of RNA. To evaluate the heterogeneity of cells with respect to the metabolism of pyrimidines, precursor incorporation was studied in isolated glomeruli and by radioautography. Incorporation into glomeruli was qualitatively similar to but quantitatively different from results in the renal cortex. Although there is obvious tissue heterogeneity, compartmentation of UTP pools is the most credible explanation for the results obtained with the renal cortex and liver. Consequently RNA and UDP-sugars may originate from two different UTP pools. Tissue heterogeneity is the likely explanation for the results obtained in the spleen. Studies of synthesis of pyrimidine and RNA, particularly in relation to growth and regeneration, must take into consideration the precursor used, the apparent existence of UTP compartmentation and the degree of cellular heterogeneity.


Biosynthesis and degradation of prolactin in the rat anterior pituitary gland. Time course of incorporation of label in vitro and evidence for rapid degradation.

Biosynthesis of prolactin was studied in anterior pituitary glands from female rats, incubated in vitro. In this system [3H]leucine was incorporated into pituitary proteins, including somatotropin (growth hormone) and prolactin. The rate of uptake of label into prolactin (and to a lesser extent into total protein) slowed considerably during the first 2 h of incubation, although the rate of uptake into somatotropin was constant for 8 h. The most probable explanation for this apparent decrease in the rate of prolactin synthesis is degradation of prolactin in the gland. Degradation of this hormone was also demonstrated by incubating prelabelled pituitaries in unlabelled medium and following the content of labelled prolactin, and by studying the hormonal content of pituitary glands (by radioimmunoassay) before and after incubation. Degradation of prolactin appears to be much more rapid than that of somatotropin, and may represent a physiological mechanism whereby over-accumulation of prolactin is prevented when secretion of the hormone has been rapidly switched off.


A study of the glycerol phosphate acyltransferase and dihydroxyacetone phosphate acyltransferase activities in rat liver mitochondrial and microsomal fractions. Relative distribution in parenchymal and non-parenchymal cells, effects of N-ethylmaleimide, palmitoyl-coenzyme A concentration, starvation, adrenalectomy and anti-insulin serum treatment.

1. GPAT (glycerol phosphate acyltransferase) and DHAPAT (dihydroxyacetone phosphate acyltransferase) activities were measured both in subcellular fractions prepared from fed rat liver and in whole homogenates prepared from freeze-stopped pieces of liver. 2. GPAT activity in mitochondria differed from the microsomal activity in that it was insensitive to N-ethylmaleimide, had a higher affinity towards the palmitoyl-CoA substrate and showed a different response to changes in hormonal and dietary status. 3. Starvation (48 h) significantly decreased mitochondrial GPAT activity. The ratio of mitochondrial to microsomal activities was also significantly decreased. The microsomal activity was unaffected by starvation, except after adrenalectomy, when it was significantly decreased. Mitochondrial GPAT activity was decreased by adrenalectomy in both fed and starved animals. 4. Acute administration of anti-insulin serum significantly decreased mitochondrial GPAT activity after 60 min without affecting the microsomal activity. 5. A new assay is described for DHAPAT. The subcellular distribution of this enzyme differed from that of GPAT. The highest specific activity of DHAPAT was found in a 23 000 gav. pellet obtained by centrifugation of a post-mitochondrial supernatant. This fraction also contained the highest specific activity of the peroxisomal marker uricase. DHAPAT activity in mitochondrial fractions or in the 23 000 gav. pellet was stimulated by N-ethylmaleimide, whereas that in microsomal fractions was slightly inhibited by this reagent. The GPAT and DHAPAT activities in mitochondrial fractions had a considerably higher affinity for the palmitoyl-CoA substrate. 6. Total liver DHAPAT activity was significantly decreased by starvation (48 h), but was unaffected by administration of anti-insulin serum. 7. The specific activities of GPAT and DHAPAT were lower in non-parenchymal cells compared with parenchymal cells, but the GPAT/DHAPAT ratio was 5--6-fold higher in the parenchymal cells.


Detection of peroxisomal fatty acyl-coenzyme A oxidase activity.

It has been postulated that the peroxisomal fatty acid-oxidizing system [Lazarow & de Duve (1976) Proc. Natl. Acad. Sci. U.S.A. 73, 2043--2046; Lazarow (1978) J. Biol. Chem. 253, 1522--1528] resembles that of mitochondria, except for the first oxidative reaction. In this step, O2 would be directly reduced to H2O2 by an oxidase. Two specific procedures developed to detect the activity of the characteristic enzyme fatty acyl-CoA oxidase are presented, namely polarographic detection of palmitoyl-CoA-dependent cyanide-insensitive O2 consumption and palmitoyl-CoA-dependent H2O2 generation coupled to the peroxidation of methanol in an antimycin A-insensitive reaction. Fatty acyl-CoA oxidase activity is stimulated by FAD, which supports the flavoprotein nature postulated for this enzyme. Its activity increases 7-fold per g wet wt. of liver in rats treated with nafenopin, a hypolipidaemic drug. Subcellular fractionation of livers from normal and nafenopin-treated animals provides evidence for its peroxisomal localization. The stoicheiometry for palmitoyl-CoA-dependent O2 consumption, H2O2 generation and NAD+ reduction is 1 : 1 : 1. This suggests that fatty acyl-CoA oxidase is the rate-limiting enzyme of the peroxisomal fatty acid-oxidizing system.


Inhibition of gluconeogenesis in isolated rat liver cells by methylenecyclopropylpyruvate (ketohypoglycin).

1. In isolated rat liver cells, hypoglycin is a less effective inhibitor of gluconeogenesis than its transamination product, methylenecyclopropylpyruvate (ketohypoglycin). 2. Methylenecyclopropylpyruvate at 0.3 mM inhibits gluconeogenesis from all substrates tested, except fructose. 3. Methylenecyclopropylpyruvate does not affect 14CO2 release from [1(-14)C]palmitate, but, in the absence of lactate, inhibits ketogenesis and causes a decrease in the [beta-hydroxybutyrate]/[acetoacetate] ratio. These effects are masked when lactate (10 mM) is present. 4. In the presence of lactate and palmitate, 0.3 mM-methylenecyclopropylpyruvate produces a fall in total acid-soluble CoA and a relative increase in short-chain acyl-CoA at the expense of CoA and acetyl-CoA without changing the ATP, ADP and aspartate contents or the [lactate]/[pyruvate] ratio. 5. Many of the effects of methylenecyclopropylpyruvate observed are consistent with inhibition of butyryl-CoA dehydrogenase and of specific CoA-dependent enzymes involved in gluconeogenesis.


Evidence for the operation of the extrahepatic lipoprotein receptor system in vivo in rats. Effect of dietary cholesterol and orotic acid, alone or in combination, on the rate of synthesis of cholesterol and fatty acid in various tissues, measured by using 3H2O.

1. The biosynthesis of cholesterol in vivo was studied at a number of tissue sites in rats by using 3H2O as precursor. Overall, the mass of cholesterol synthesized was in good agreement with the rate of cholesterogenesis, as determined by kinetic analysis of cholesterol specific-radioactivity-time curves after administration of radiolabelled cholesterol. 2. Dietary cholesterol increased the circulating concentration of cholesterol and inhibited endogenous cholesterogenesis, with concomitant increases in the concentration of esterified cholesterol, in all tissues studied. Addition of ororic acid to the cholesterol-supplemented diet tended to reverse each of these changes in extrahepatic tissues. 3. The co-ordinated change in cholesterol biosynthesis and esterification, with no change in total cholesterol content, in extrahepatic tissues, is attributed to control by receptor-mediated lipoprotein uptake. 4. Further reduction of the concentration of the apoprotein B-containing lipoproteins by addition of orotic acid to a diet without supplementary cholesterol did not further enhance cholesterogenesis. We consider that the relatively high rates of extrahepatic cholesterogenesis in normolipidaemic rats are attributable to the low concentration of low-density lipoprotein.