Participation of immunoglobulin and the alternative complement pathway in opsonization of Bacteroides fragilis and Bacteroides thetaiotaomicron.

Studies were conducted to determine the requirements for immunoglobulin and complement for opsonization of Bacteroides fragilis and Bacteroides thetaiotaomicron. The ability of human sera depleted of immunoglobulin or complement components to promote phagocytosis and intracellular killing of the strains of Bacteroides by human leukocytes was measured in vitro under anaerobic conditions. Neither hypogammaglobulinemic sera nor pooled normal human serum (PNHS) heated at 56 C for 30 min supported phagocytosis and killing of the strains of Bacteroides. Sera depleted of terminal complement components by treatment with inulin or cobra venom factor and C8-deficient human serum did not support phagocytosis of the test strains. PNHS depleted of C3, factor B, or factor D also did not support phagocytosis of either strain. Dose-dependent restoration of the opsonic activity of factor B-depleted serum was accomplished by purified human factor B but not by human C2. The results indicated that immunoglobulin and components of the alternative complement pathway participate in opsonization of the strains of Bacteroides tested in this study.


Reactivation of herpes simplex virus after decompression of the trigeminal nerve root.

Reactivation of herpes simplex virus was prospectively studied in patients after microneurosurgical decompression of the trigeminal sensory root, a new operation for trigeminal neuralgia in which the nerve is not sectioned. Reactivation was detected in 28 (50%) of 56 patients. Virus was cultured from oropharyngeal secretions in 25 patients, and 21 patients developed cutaneous herpetic lesions. Seven patients had positive throat-wash (TW) cultures but did not develop lesions, and the converse occurred in three patients. Eighteen patients had both positive TW cultures and herpetic lesions. In eight of nine instances in which a sequence was determinable, TW cultures were positive before lesions developed. A history of recurrent herpes labialis was associated with a higher risk of developing reactivation postoperatively (59.4% vs. 31.6%, P less than 0.05). These observations suggest that minimal stimulation or inapparent trauma to the trigeminal sensory root is sufficient to activate latent herpes simplex virus in humans. These patients provide unique opportunities to study immunologic responses and therapeutic measures.


Cerebrospinal fluid otorrhoea and otorhinorrhoea following closed head injury.

A discussion of acute traumatic CSF otorrhoea and otorhinorrhoea is presented. The incidence of meningeal infection is reviewed and the management of these cases is outlined with special emphasis on the indications for surgical intervention and the otological procedures available. Two patients who sustained transverse fractures of the petrous temporal bone are described in whom subsequent attacks of meningitis were prevented by a new, simple yet effective operation.


Further observations on the vestibulo-dural channel.

A channel between the vestibular aqueduct and the dura, corresponding in texture to the main aqueduct, has been observed in an un-negligible number of cases. All attempts to establish a connection between this phenomenon and a variety of clinical entities, among them Menière's disease, have so far been unsuccessful.


Otogenic intracranial hypertension. Otitic hydrocephalus.

Otogenic intracranial hypertension is a rare complication of suppurative otitis media. Two patients with the typical features of the disease are presented. An historical review of the literature on the subject and a discussion of the differential diagnosis have been carried out. In the light of recent neuro-otological advances the management has been reappraised.


Malignant otitis externa.

A case is described of malignant otitis externa which was cured by a regime of general and local treatment, including the use of the antibiotic Tobramycin and timely mastoid surgery. The origins, progression, diagnosis and treatment of the disease are discussed with reference to some of the increasingly numerous reports in the literature. Reports disclose an increasing incidence and also an improved prognosis. The former is probably related to the survival of more elderly diabetics and the latter to a better understanding of the disease process and to early medical and, if necessary, surgical treatment. An important feature regarding treatment has been the advent of powerful specific antibiotics including Tobramycin.


A rare case of malignant otitis externa in a non-diabetic patient.

A case of an elderly non-diabetic patient suffering from malignant otitis externa is reported. The organisms were resistant to Gentamicin and the cause of death was a sub-dural abscess causing pressure on the pons.


Leiomyoma of the nasal cavity. Report of a case.

A 76-year-old woman had a leiomyoma of the nasal cavity. There are three cases of leiomyomas of the nasal cavity previously reported.


Oesophageal papillomata in the child.

This is a case report of a 6-year-old female child with asymptomatic multiple squamous papillomatosis involving the hypopharynx and the entire length of the oesophagus. Total spontaneous regression of the papillomata occurred within  2 years of presentation. Associated asymptomatic laryngeal papillomata were removed by suction diathermy under general anaesthesia. The diagnosis was confirmed by direct microlaryngoscopy, oesophagoscopy, barium swallow and histology. The laryngeal hypopharyngeal and oesophageal lesions were identical histologically and macroscopically.


A schwannoma of the parotid gland. Report of a case.

An unusual case of multiple schwannomas of the parotid gland in a 44-year-old male is presented, and the natural history of the disease is discussed. Neural tumours of the salivary glands are rare, and the treatment of choice is surgery. Recurrence seems to be unusual unless the excision is incomplete.


Changes in oestradiol-17beta binding in the hypothalami and pituitary glands of persistently infertile ewes previously exposed to oestrogenic subterranean clover: evidence of alterations to oestradiol receptors.

The binding of [3H]oestradiol-17beta to the hypothalamus and pituitary gland of clover-affected permanently infertile and control ovariectomized ewes was compared in vivo and in vitro. When [3H]oestradiol-17beta was infused into the carotid artery (10 ng/min), the total homogenate and the nuclear and protamine-precipitable cytosol fractions of hypothalami and pituitary glands from clover-affected ewes bound significantly more[3H]oestradiol than those of the controls. Cytoplasmic oestradiol-17beta receptors from the pituitary glands of clover-affected ewes showed a significantly lower apparent association constant and a higher number of binding sites/mg protein in vitro. It is suggested that the hypothalami and pituitary glands of ewes made permanently infertile by oestrogenic clover are less sensitive to feedback regulation of oestradiol-17beta at physiological levels.


Elimination of infused arginine-vasopressin and its long-acting deaminated analogue in rats.

Arginine-vasopressin (AVP) and deamino-arginine-vasopressin (dAVP) were infused into rats. When the concentrations of the two peptides were steady, the rate of clearance of AVP from the plasma was six times the rate of clearance of alphaAVF. Only 6% of the infused AVP was excreted unchanged in the urine, whereas approximately 100% of the dAVP was excreted. When the infusions were stopped, AVP disappeared from the plasma much more rapidly than dAVP. The plasma concentrations of the two peptides did not decay as simple exponential functions, suggesting that both AVP and dAVP entered a slowly exchanging compartment or compartments during prolonged infusion. These differences in the metabolic clearance of AVP and dAVP may well explain the prolonged antidiuretic effect of dAVP in rats.


Reversal of betamethasone-induced inhibition of intestinal calcium absorption by 1alpha-hydroxycholecalciferol.

The intestinal absorption of calcium has been studied in conscious, unstressed pigs, using a modification of the double isotope technique. The oral administration of betamethasone (1 mg/day) to four pigs (25--33 kg) for 4 weeks reduced the calcium absorption coefficient, calculated after the intravenous and oral administration of 47Ca2+, by a mean value of 66%. The oral administration of 1alpha-hydroxycholecalciferol (2 microgram/day) in combination with beta-methasone (1 mg/day) for a further 4 weeks returned the absorption coefficient to the control value.


Foetal and maternal plasma concentrations of 13, 14-dihydro-15-oxo-prostaglandin F in the mare during late pregnancy and at parturition.

The concentrations of 13, 14-dihydro-15-oxo-prostaglandin F(PGFM), the stable metabolite of prostaglandin F, were measured in the plasma of catheterized mares and foetuses and non-catheterized thoroughbred mares and ponies during the last months of gestation. The plasma concentration of PGFM increased gradually towards term in all groups of animals. During the operation for insertion of catheters, maternal and foetal concentrations of PGFM were high, but the values fell to basal levels 24--48 h after the operation. It was found the preoperative starvation (24 h) led to a rise in the concentration of PGFM in the maternal plasma. The raised concentrations of PGFM during the operation were associated with low progestogen and high oestrogen concentrations in umbilical venous plasma. The subsequent survival period of the catheterized foal was inversely related to the maximum concentration of PGFM were studied during normal parturition in thoroughbred mares, during oxytocin-induced delivery in non-catheterized ponies and during premature delivery or abortion in the catheterized animals. The greatest increase in the concentration of PGFM was seen in the thoroughbred animals during second-stage labour; oxytocin also resulted in a very rapid rise in the level of PGFM, which remained high until delivery. In the catheterized animals, the birth of live foetuses was associated with a rise in the concentration of PGFM in both foetal and maternal plasma during the last 2 h before delivery. Less consistent changes were found during abortion.


Effect of luteinizing hormone of the lipid composition of rat ovaries.

The lipid composition of immature rat ovaries was examined after induction of ovulation with pregnant mare serum gonadotrophin and human chorionic gonadotrophin and subsequent (7--8 days later) stimulation with 10 micgogram LH. Two hours after the administration of LH, there was a decrease of approximately 50% in the concentration of cholesteryl esters in the ovary. The percentages (by weight) of sterol esters containing stearate, linoleate, eicosatrienoate and arachidonate were reduced by LH treatment, whereas the percentage of the C24:4 acid increased. No changes were observed in either the concentrations or fatty acid composition of phospholipids and triglycerides. These observations suggest that the metabolism of cholesteryl esters is acutely affected by LH and that sterol esters bearing long-chain polyunsaturated fatty acids are preferentially mobilized. Liberation of these unsaturated fatty acyl moieties may have significant effects on metabolism in the ovarian cell.


Action of prostaglandin E2 on the release of catecholamines from the canine adrenal gland and its interaction with acetylcholine.

The effect of prostaglandin E2 (PGE2) on the secretion of adrenaline and noradrenaline by the adrenal gland and the interaction between PGE2 and acetylcholine in the adrenal medulla were examined in anaesthetized dogs. In splanchnicotomized dogs, i.v. injection of PGE2 failed to induce any secretion of catecholamines from the adrenal gland, whereas administration of PGE2 into the lumboadrenal artery resulted in a slight, approximately dose-dependent increase in catecholamine secretion within 2 min of the injection. This effect of PGE2 was unaffected by i.v. administration of atropine. Intravenous administration of acetylcholine 1 min after the administration of PGE2 into the lumboadrenal artery of splanchnicotomized atropine-treated dogs had a markedly greater effect on adrenal catecholamine secretion; the resultant output was about twice that evoked by acetylcholine in the absence of PGE2. The effect was more than additive, since the response to acetylcholine was at least one order of magnitude greater than that to PGE2. This indicates that PGE2 and acetycholine may act synergistically in the adrenal medulla.


Effects of low calcium and low phosphorus diets on the duodenal absorption of calcium in betamethasone-treated chicks.

The effect of oral administration of betamethasone (25 microgram kg-1 day-1) on the duodenal absorption of calcium has been studied in chicks using the ligated loop technique in vivo. The chicks were fed normal calcium, normal phosphorus (NCaNP), low calcium, normal phosphorus (LCaNP) or normal calcium, low phosphorus (NCaLP) diets. Daily oral administration of betamethasone for 2-3 weeks markedly reduced the absorption of calcium in chicks fed the NCaNP diet, but did not significantly affect the adaptation in absorption when the NCaLP or LCaNP diets were fed for the same period of time. In one group of chicks, betamethasone was administered daily for 10 days before the birds were transferred to the NCaLP or LCaNP diets. Adaptation was again unaffected by betamethasone treatment. Administration of betamethasone caused a marked retardation in growth-rate, hypercalcaemia and an increased percentage of ash in the tibiae.


Rate of testicular maturation, in relation to gonadotrophin and testosterone levels, in quail exposed to various artificial photoperiods and to natural daylengths.

Rates of testicular growth and plasma levels of FSH, LH and testosterone were determined in Japanese quail exposed to various fixed photoperiods (number of hours of light: number of hours of darkness): 12L : 12D, 13L : 11D, 14L : 10D, 16L : 8D and 20L : 4D and to natural daylengths. All five artificial photoperiods stimulated spermatogenesis, with the testes reaching maturity after 30-40 days. Maximum rates of testicular growth occurred with 14L : 10D, 16L : 8D or 20L : 4D but the rate was reduced by 50% in birds exposed to 12L : 12D.. This reduction was due to decreased growth in the seminiferous tubule epithelium (and hence in tubule diameter); the duration of spermatogenesis hardly being affected. Near maximum growth rates occurred with 13L : 11D. The hormone profiles offer an explanation for the differential rates of testicular growth. In the three longest photoperiods, FSH rose from 20 ng/ml to peak levels of 300-400 ng/ml after 10 days. As the testes matured, so the level of FSH decreased to 50-100 ng/ml. This pattern was not seen under 12L : 12D ; the level of FSH rose slowly to about 100 ng/ml and showed no peak of secretion. With 13L : 11D a small peak was found, which decreased at maturity. In quail with testes is greater than 1500 mg, the level of FSH was invariably about 100 ng/ml. Patterns of LH secretion were rather similar with all treatments, but testosterone was affected by photoperiod; lower levels were found under 12L : 12D than 20L : 4D. The rate of photoperiodically induced testicular growth was proportional to the levels of FSH, and possibly also testosterone, in the circulation. Outdoors, testicular growth began when daylengths reached about 12 h. Maturity occurred within the next 40 days. The levels of FSH rose steadily but did not show a peak of secretion. In general, the highest levels of hormone were found in July just before gonadal regression which occurred when the daylengths were still quite long.


Drug effects on responding maintained by stimulus-reinforcer and response-reinforcer contingencies.

The effects of pentobarbital and d-amphetamine were assessed on key pecking by pigeons under conventional single-key multiple schedules and under two-key multiple schedules in which discriminative stimuli appeared on one key (stimulus key) while pecks on a second key (constant key) produced food. Pecks on the stimulus key had no scheduled consequences. A 60-second variable-interval schedule operated in one component of each multiple schedule: either extinction or a 60-second variable-time schedule operated in the alternate component. When the alternate-component schedule was extinction, a high rate of responding was maintained in the variable-interval component of the single-key schedule; responding on both keys was maintained in the variable-interval component of the two-key schedule. Pentobarbital increased responding in the variable-interval component of the single-key schedule and increased stimulus-key, but not constant-key responding in that component of the two-key schedule. When the alternate-component schedule was changed to variable time, responding declined in the variable-interval component of the single-key schedule; stimulus-key responding was no longer maintained under the two-key schedule. Pentobarbital decreased responding in the variable-interval component of both schedules. With an exception, d-amphetamine only decreased responding in the variable-interval component of the single- and two-key schedules both when the alternate-component schedule was extinction and when it was variable time. The results suggest that the effects of pentobarbital, but not d-amphetamine, depend on the nature of the contingency (stimulus-reinforcer, response-reinforcer) that maintains responding.


Electron microscopic studies on the structure of motile primordial germ cells of Xenopus laevis in vitro.

Primordial germ cells (PGCs) of Xenopus laevis have been isolated from early embryos and kept alive in vitro, in order to study the structural basis of their motility, using the transmission and scanning electron microscope. The culture conditions used mimicked as closely as possible the in vivo environment of migrating PGCs, in that isolated PGCs were seeded onto monolayers of amphibian mesentery cells. In these conditions we have demonstrated that: (a) No significant differences were found between the morphology of PGCs in vitro and in vivo. (b) Structural features involved in PGC movement in vitro include (i) the presence of a filamentous substructure, (ii) filipodial and blunt cell processes, (iii) cell surface specializations. These features are also characteristic of migratory PGCs studied in vivo. (c) PGCs in vitro have powers of invasion similar to those of migrating PGCs in vivo. They occasionally become completely surrounded by cells of the monolayer and, in this situation, bear striking resemblance to PGCs moving between mesentery cells to the site of the developing gonad in stage-44 tadpoles. We conclude that as far as it is possible to assess, the behaviour of isolated PGCs in these in vitro conditions mimics their activities in vivo. This allows us to study the ultrastructural basis of their migration.


Postembryonic development of the visual system of the locust, Schistocerca gregaria. II. An experimental investigation of the formation of the retina-lamina projection.

In the compound eye of the locust, Schistocerca gregaria, neurons from the retina project to the lamina in a precise topographical mapping. The formation of this projection was investigated in grafting experiments which altered the spatial or temporal relationship between the retina and the lamina. The results show that retina axons tend to grow along the paths of adjacent axons, with no indication of specificity for their normal termination sites. It is suggested that the orderly sequence of retina differentiation during normal development plays a major role in imposing pattern both upon the developing projection and, through some form of inductive interaction between retina and lamina neurons, upon the lamina.


Studies on dwarf larvae developed from isolated blastomeres of the starfish. Asterina pectinifera.

Not only a whole denuded egg, but also blastomeres isolated from 2-, 4- and 8-cell starfish embryos developed into morphologically normal, but dwarf bipinnariae, the sizes of which were roughly proportionate to that of the respective original blastomeres. Some of the blastomeres isolated from the 16-cell stage were also capable of developing into the larval stage. All isolated blastomeres divided in good synchrony with the control embryos. Blastulae of all groups gastrulated within quite a short range of time, around 14-5 h after insemination at 20+/-1 degrees C, although one-third of the 1/8-blastula missed this chance but gastrulated by 19.5 h. The number of constituent cells of the 1/8-gastrula was counted to be about 560, which corresponds roughly to one-half that of the 1/4-, one-fourth of the 1/2- and one-eight of the 1/1-gastrula. This ratio also fitted roughly for the total cell volume. The results are compared with those of other invertebrate species, as well as of some vertebrates, and are discussed in connexion not only with the concepts of 'regulative' and 'mosaic' eggs, but also with a criterion that does not fit into either of these; the developmental system of the mammals.


In vivo and in vitro studies on the hypoblast and definitive endoblast of avian embryos.

An unusual example of the invasion of one tissue by another occurs during gastrulation in the chick embryo when the definitive endoblast becomes inserted into the hypoblast. The two tissues were examined morphologically by SEM and TEM. They resemble each other in being of an epithelial type, though neither possesses a basal lamina. The definitive endoblast cells are flatter than the hypoblast cells and more closely attached to one another. When they were explanted in hanging drop cultures, the two tissues were found to exhibit differences in their behaviour. In comparison with the definitive endoblast, the hypoblast cells attached more readily to the glass, produced larger ruffle membranes, moved more rapidly, showed poorer contact-inhibition of locomotion and showed a greater tendency to break away from the main explant. When a hypoblast explant was confronted with a definitive endoblast explant, the hypoblast cells became displaced by the definitive endoblast. The hypoblast explant tended to fragment into smaller groups of cells, many of which migrated around the definitive endoblast, thus mimicking the situation in vivo. Control experiments comprised confronting hypoblast with hypoblast, hypoblast with somites, definitive endoblast with definitive endoblast, and definitive endoblast with somites. The hypoblast explants behaved in a consistent manner, always fragmenting when coming into contact with cells from a confronting explant. The definitive endoblast explants showed more contact inhibition of locomotion when confronted with definitive endoblast or with somites than when confronted with hypoblast. It is suggested therefore that the ability of the hypoblast cells to separate from one another may play an important role in the penetration of the hypoblast by the definitive endoblast both in vitro and in vivo.


Cell adhesiveness and embryonic differentiation.

The aim of the investigation was to decide whether changes in cell to cell adhesiveness took place during embryonic differentiation. The technique of Curtis (1969) was used to measure the adhesive behaviour of several types of ectodermal, neural and mesodermal cells of the chick embryo at stages 7 and 12 of differentiation. Cells dissected from segmented mesoderm were found to be more adhesive than cells from unsegmented mesoderm. Cells from the ectoderm were more adhesive than those from the neural tissue, at both stages 7 and 12. Cells from both ectoderm and neural tissue became more adhesive between stages 7 and 12. It is concluded that an increase in adhesiveness may play a role in somite segmentation, but not in neural tube formation.


[Cytophysiologic differentiation in the epithelial region of the uropygial gland in the duck embryo Anas platyrhynchos].

The uropygial gland (preen gland), an epidermal derivative, is a bilobed, lipid-secreting gland located over the base of the tail of most birds. In the duck embryo Anas platyrhynchos, the internal branching morphogenesis of preen gland is set up at the 17th day of incubation. Each glandular lobe is made of numerous epidermal columns each of which is terminated by a bulb or end-bud. The functional differentiation of the end-buds and the development of the cellular columns into collecting ducts were investigated. The ductal epithelium, separated from the mesoderm by a continuous basal lamina, is keratinized just as in normal embryonic avian epidermis. The features which indicate glandular differentiation in the end-buds were described. Lipogenesis results from progressive cellular differentiation characterized by proliferation and development of smooth membranes. The direct ecto-mesodermal contacts, which were observed at the end-buds after the establishment of morphogenetic pattern and before the onset of glandular secretory activity, suggest that a new interaction mechanism would be required to initiate the functional differentiation.


Biochemical changes in developmentally retarded Xenopus laevis larvae. I. The lens crystallin transition.

Premetamorphic tadpoles of Xenopus laevis reared in water containing 0.01% propylthiouracil are developmentally retarded and metamorphosis is prevented. When uncrowded, they continue to grow to a giant size. Moderate crowding leads to a slower rate of growth. Thus morphologically premetamorphic tadpoles were produced with lens diameters appropriate to either normal premetamorphic, climactic or post-metamorphic animals. The lens crystallins of such tadpoles have been separated by immunoelectrophoresis and polyacrylamide gel electrophoresis. The crystallin pattern was correlated with lens diameter rather than with body stage. Giant retarded larvae possessed crystallin patterns identical to those or normal adults. The thyroid antagonist propylthiouracil is therefore unable to prevent the lens crystallin transition, the beginning of which is normally temporally correlated with metamorphosis.


Regional differences in mesenchymal cell morphology and glycosaminoglycans in early neural-fold stage rat embryos.

Rat embryos with two to four pairs of somites (day 9 of gestation) were examined by scanning electron microscopy and Alcian blue staining. The neural folds, which represent only future brain region at this stage, form a pair of elongated hemispheres with a deep neural groove between them. In transverse section the neural ectoderm is biconvex; the cranial mesenchyme cells beneath them are widely separated by extracellular matrix (ECM) and are joined to each other and to the ectodermal basement membrane by fine cytoplasmic processes and strands of ECM material. In contrast, mesenchyme cells close to the primitive streak are closely packed, having broad areas of surface contact and only small amounts of ECM. The nature and distribution of ECM, cell surface, and basement membrane glycosaminoglycans (GAG) were investigated by staining with Alcian blue at specific pH values in combination with enzyme pretreatments, and at various critical electrolyte concentrations. The results indicate that the GAG of the ectodermal basement membrane, mesenchymal ECM and mesenchymal cell surfaces are in continuity with each other and consist largely of hyaluronate and chondroitin sulphates. Differences in morphology and histochemistry of neural fold and primitive streak regions are discussed in relation to their possible morphogenetic significance.


The role of the cell surface in the migration of primordial germ cells in early chick embryos: effects of concanavalin A.

Effects of concanavalin A (Con A) on the morphology and migration of primordial germ cells (PGCs) in stage-6 to -12 chick embryos were investigated. Con A, at a sublethal dose (10 microgram/ml), inhibited migration of PGCs from the germinal crescent area to other parts of the embryo. Affected PGCs were more rounded without the usual cytoplasmic extensions, but the integrity of other structures was unaffected. Nearly identical results were obtained with another lectin, wheat germ agglutinin (10 microgram/ml). Histochemistry using Con A-horseradish peroxidase revealed that PGCs in control embryos had a thin, rather uniform layer of extracellular coat material (ECM). Con A appeared to alter the distribution of ECM on PGCs, i.e. some parts of the cell surface were devoid of any detectable ECM, while others had small, scattered patches of ECM. Con A effects were alleviated by alpha-methyl-D-mannoside. Overall results of the present study indicated that the observed inhibition of PGC migration in early chick embryos is a consequence of Con A-induced alterations of cell surface properties.


Cell proliferation and cell density of mesenchyme in the maxillary process and adjacent regions during facial development in the chick embryo.

Cell proliferation, as measured by DNA labeling indices was analyzed during the early development of the maxillary process. Chick embryos were labeled with [3H]thymidine for 1 h and processed for autoradiography. The percentage of labeled mesenchymal cells was determined within delineated areas in the maxillary processes and in adjacent regions. Analysis of labeling indices in each of the areas at successive stages of development demonstrated a pattern of declining rates of cell proliferation with advancing developmental age. Cell proliferation in adjacent regions declined earlier and, in some instances, faster than it did in the maxillary process. Cell density was measured in the maxillary process and the roof of the stomodeum and was found to be higher in the maxillary process throughout the period studied. Cell density and cell proliferation data were analyzed with reference to the operation of 'density-dependent inhibition' of growth as a regulatory mechanism for the observed changes. 'Density-dependent inhibition' of growth was not a satisfactory explanation for the observed differences between the maxillary process and adjacent regions.


Ultrastructural study of the development of the auditory tympana in the cricket Teleogryllus commodus (Walker).

The cuticle in the tympanal area of immature crickets, Teleogryllus commodus (Walker), is ultrastructurally indistinguishable from that elsewhere on the prothoracic leg. It is only in the pharate adult that changes associated with development of the tympana first appear. In pharate adults and adults the external layer of the tympana consists of a layer of electron-dense material overlying a layer where the electron-dense material is interspersed with cuticle in which the bundles of microfibrils are coarser and more loosely arranged than elsewhere in the leg. The innermost portion of the tympana consists of this same type of cuticle without the electron-dense material. Associated with the appearance of the electron-dense material in the tympana of the pharate adult is a change in the toluidine blue staining properties from blue to deep purple. The reaction of the tympana in acid and base is consistent with their being composed of chitin. There are no major deposits of resilin in the tympana. In the first few days following the imaginal ecdysis the posterior tympanum and underlying trachea come into tight apposition due to the withdrawal of the epidermal cells. The epidermal cells do not withdraw from beneath the anterior tympanum. The surrounding non-tympanal cuticle continues to thicken for several weeks with the result that in the mature adult the posterior tympanum serves as an acoustic window in the thick cuticle of the leg. The functional significance of the anterior tympanum has not been established.


Retino-tectal projections from half-ventral and half-dorsal eye rudiments in Xenopus.

When the ventral half of a developing eye in Xenopus larvae was removed at stage 32, the remaining fragment rounded up and developed into an eye which looked macroscopically normal by mid-larval stages. Eyes from half-dorsal rudiments were usually small, had more than one ventral fissure, and showed abnormal pupils. The contralateral retinotectal projection was always found to be normally ordered when mapped in later tadpole stages, or, just after metamorphosis. No mirror-image duplicated maps were seen, as was found previously in eyes deriving from half-nasal and half-temporal rudiments. It is concluded that the 'rule of distal transformation' does not apply to eyes which are generated from embryonic rudiments.


Identification and distribution of gap junctions in the mesoderm of the developing chick limb bud.

Sub-ridge, core, anterior and posterior borders of mesoderm were dissected from stages 22-24 chick wing buds to investigate whether structures for intercellular coupling develop between mesenchymal cells. Fine structure was examined using techniques of transmission electron microscopy, freeze-fracture and scanning electron microscopy. Gap (communicating) junctions which were observed between mesenchymal cells of all limb bud regions were distributed between apposed cell bodies, points of contact between cell processes and other cell bodies, and between contacting tips of slender cell projections. In addition particularly in the the subridge region, filopodia were observed to extend through the intercellular matrix to contact other cells several micrometers distant. The observations reported in this paper show that mesodermal cells throughout the limb have the structural capability for electrotonic and metabolic coupling during a critical period of morphogenesis in the avian limb. Whether intercellular signals which are thought to be transmitted through gap junctions are active in normal limb development remains to be investigated.


Neurones in the leech that facilitate an avoidance behaviour following nearfield water disturbances.

1. A multimodel, multisegmental interneurone (Röhde's fibre, RF) and previously identified mechanoreceptors (T-cells) are shown to respond to nearfield disturbances. Both the T-cells and RF can fire for hundreds of milliseconds following a brief stimulus, and both have subthreshold excitatory synapses onto motor neurones that cause longitudinal contraction of the body wall, an avoidance response. 2. Natural stimulation or electrical stimulation of T-cells in one hemiganglion causes synaptic excitation of T-cells in adjacent ipsilateral hemiganglia and re-excitation of T-cells in the hemiganglion stimulated. A model of repetitive T-cell activity that incorporates previously described synapses among T-cells is presented: the T-cells in adjacent ipsilateral hemiganglia form a reverberatory circuit, re-exciting one another via electrical synapses; repetitive firing is terminated by synaptic inhibition onto T-cells provided by an interneurone excited by the T-cells. With repeated stimulation (0.1--0.2 Hz, 0.2 ms pulses) of a segmental root (directly exciting all the T-cells of a hemiganglion), the number of T-cell impulses per stimulus decreases. Facilitation of inhibition may contribute to the response decrement. 3. The T-cell-RF pathway is investigated. T-cell stimulation can elicit RF impulses in the same and in adjacent ganglia. The long delay between mechanoreceptor stimulation and a response in the interneurone suggests that spatial and temporal summation of T-cell inputs may be required to reach firing threshold in the interneurone. 4. The impulse frequency of the RF response was compared for a travelling surface wave that is approaching a segment v. one that is moving away from the segment. It was found that the frequency was greater as the stimulus approaches; this should allow more effective temporal summation of the subthreshold synaptic potentials which RF evokes in motor neurones that cause longitudinal contraction of the body wall. Therefore, the probability of contraction is greater in segments toward which a stimulus is moving.


The metabolic cost of flight in unrestrained birds.

Oxygen consumption and carbon dioxide production were measured during flight in unrestrained starlings by a new method. Mean RQ after the first 30 min of flight was 0.69 +/- 0.08 (+/- S.D.). Mean rate of carbon dioxide production was 19.7 +/- 2.2 ml CO2/min, which corresponds to a metabolic rate of 8.9 +/- 1 W. Metabolic rate during flight did not change significantly over a range of air speeds from 8 to 18 m/s and birds would not fly at speeds outside of this range. Current theories of bird flight predict a large change in metabolic rate over the same range of speeds. Wingbeat frequency was constant at 12 +/- 0.5 Hz. Wingbeat amplitude reached a minimum at a speed of 14 m/s and increased at both higher and lower speeds. Angle between the body and horizontal was least at high speeds and increased at low speeds. As existing theories do not take into account the change of drag resulting from changes in body attitude, this may be a cause of the discrepancies between theory and observation.


Evaporative cooling and water balance during flight in birds.

The rate of evaporative cooling was calculated from the rate of mass loss in starlings (Sturnus vulgaris) during 90 min flights in a wind-tunnel. Evaporative heat loss ranged from 5% of the metabolic rate at -5 degrees C to 19% of the metabolic rate at 29 degrees C. Radiation and convection accounted for the balance of the heat loss. On average, starlings dehydrated during flights at all temperatures above 7 degrees C. The comparison of these results with data from field studies, which indicate that long-distance migrants do not dehydrate, suggests that migrants may maintain water balance by ascending to colder air in which convection carries off most of the heat produced.


Neuronal control of swimming in the medicinal leech. IV. Identification of a network of oscillatory interneurones.

Four oscillatory interneurones that appear to be the principal components of the central swim oscillator of Hirudo medicinalis have been identified on each side of the segmental ganglia of the ventral nerve cord. During 'swimming' episodes of an isolated nerve cord preparation each interneurone undergoes a polarization rhythm that is phase-locked with the impulse burst rhythm of the motor neurones known to drive the swimming movement. Passage of current into any of the interneurones can shift the phase of the swim rhythm. One of the interneurones projects its axon rearward to posterior ganglia and the other three project their axons frontward to anterior ganglia. The oscillatory interneurones are connected both intra- and interganglionically to form a topologically complex intersegmental network of concatenated ring circuits that possess the feature of recurrent cyclic inhibition. Theoretical analysis and electronic analogue models show that the network is inherently oscillatory and can produce both a cycle period and intra- and intersegmental phase relations of its elements that are appropriate for generating the body wave of the swimming movement.


Neuronal control of swimming in the medicinal leech. V. Connexions between the oscillatory interneurones and the motor neurones.

A network of intra- and intersegmental synaptic connexions has been identified in the ventral nerve cord of the leech that links the set of oscillatory interneurones of the central swim oscillator to the motor neurones commanding the swimming rhythm. Excitatory connexions lead from oscillatory interneurones to both excitatory and inhibitory motor neurones, whereas inhibitory connexions lead from oscillatory interneurones to only the inhibitory motor neurones. Connexions leading from a motor neurone back to the oscillatory interneurones were found in only one exceptional case, an inhibitory motor neurone previously known to have access to the central swim oscillator. This network of identified connexions can account reasonably well for the mechanism by which the oscillatory interneurones drive their follower motor neurones into the phasic activity pattern characteristic of the swimming movement.


Regulation of arterial blood pressure in Australian tiger snakes.

1. Blood pressure was measured in the dorsal aorta of restrained, unanaesthetized tiger snakes (Notechis scutatus) at different body temperatures during graded, passive tilt. Aortic blood pressure in horizontal snakes showed no significant change over a range of body temperatures between 18 and 33 degrees C (mean of measurements on 16 snakes = 42.2 +/- I.98 mmHg), while heart rate increased logarithmically (Q10 approximately 2.5). Blood pressure was stable during heating and cooling between body temperatures of 15 and 30 degrees C, but the pressure was 10--50% higher during heating than during cooling. 2. Head-up tilt usually caused a brief fall in pressure at heart level followed by partial or complete recovery and tachycardia. At the cessation of tilt, there was a characteristic overshoot of the blood pressure followed by readjustment to control (pretilt) levels. Head-down tilt typically increased pressure which then either stabilized or returned toward pretilt levels. Heart rate changes during head-down tilt were not consistent in direction or magnitude. Stabilized pressures at mid-body usually increased following head-up tilt and decreased following head-down tilt, indicating physiological adjustment to posture change. Blood pressure control was evident at body temperatures ranging from 10 to 38 degrees C, but was most effective at the higher and behaviourally preferred temperatures. 3. Propranolol lowered heart rate but did not influence pressure in horizontal snakes. During head-up tilt propranolol eliminated or reduced tachycardia and sometimes reduced the efficacy of pressure compensation for tilt. Phentolamine increased heart rate, lowered blood pressure, and eliminated pressure regulation during tilt. The results suggest that sympathetically mediated reflexes assist central blood pressure regulation in the tiger snake, with vasomotor adjustments having greater importance than changes in heart rate.


Control of the acute phase response. Demonstration of C-reactive protein synthesis and secretion by hepatocytes during acute inflammation in the rabbit.

To determine the cell of origin of C-reactive protein (CRP) and to cast light on the mechanisms leading to the acute phase response, we used an immunoenzymatic technique to visualize this protein in livers from rabbits at intervals after intramuscular injection of turpentine. CRP was detected only in hepatocytes. 8 h after turpentine injection, CRP was demonstrated in occasional periportal hepatocytes. With time, larger numbers of positive cells were detected successively in perilobular, midlobular, and centrilobular areas. On electron microscopy, CRP was detected in rough endoplasmic reticulum (RER), smooth endoplasmic reticulum (SER), and Golgi apparatus (GA). When colchicine was administered to inhibit cellular secretion of CRP, intensity of reaction and number of CRP-containing hepatocytes were substantially greater than without colchicine, but the sequence of intralobular distribution was similar. At peak serum response 38 h after turpentine injection, CRP could be demonstrated in most hepatocytes. Electron microscopic studies showed accumulation of CRP on membranes and lumina of RER, SER, GA, and in cytoplasmic vacuoles. These findings indicate that CRP is produced by progressively increasing numbers of hepatocytes after inflammatory stimulus and suggest that a mediator, acting initially in portal zones, is responsible for recruitment of cells to CRP production.


Leukocyte surface origin of human alpha1-acid glycoprotein (orosomucoid).

Specific antibodies against human alpha1-acid glycoprotein reacted with human lymphocytes, granulocytes, and monocytes. The antigen on the leukocytes is an externally located integral membrane glycoprotein which is made by the cells and has an apparent mol wt of 52,000. It is released from cells in vitro to the culture medium. The mol wt of the soluble fragment is 41,000, which corresponds to that of alpha1-acid glycoprotein in serum and urine. Peptide mapping confirmed that the main part of the cellular membrane antigen consists of alpha1-acid glycoprotein with an additional, probably hydrophobic fragment. This finding may partially explain the increase in the serum levels of alpha1-acid glycoprotein observed in many disorders involving leukocyte proliferation. In addition, the known sequence homology of alpha1-acid glycoprotein with immunoglobulins can now be more easily understood by their origin in similar cell types.


Isolation and characterization of IgG molecules expressing latent group b allotypes from pedigreed b4b4 rabbits.

Latent group b markers were detected in sera, in IgG preparations, and on isolated L chains from rabbits bred for homozygosity at the b locus. Serologic analysis of sera from an extended family of homozygous b4 rabbits revealed the presence of latent b allotypes in 5 of 37 sera tested. Latent b5 and b9 markers were identified; none of the sera tested contained latent b6. In two instances, the level of latent b9 allotypes was sufficiently high to permit isolation and detailed serologic characterization of the immunoglobulin population bearing this allotype. The fact that latent allotypes were detected in pedigreed homozygous rabbits minimizes the possibility that lymphoid cell chimerism is involved in latent allotype expression. Furthermore, characterization of the b9 IgG population indicates that the latent allotypic determinants do not reside on a subset of molecules with dual allotypic reactivity.


An approach to the development of new drugs for African trypanosomiasis.

The inability of the bloodstream form of Trypanosoma brucei brucei to decompose hydrogen peroxide forms the basis of our attempt to develop new pharmacological agents to kill these organisms. Approximately 1-3% of the oxygen consumed by these parasites appears in the form of hydrogen peroxide. Our previous observation that free radical initiators such as heme and hematoporphyrin D proved to be trypanocidal in vitro and in vivo, respectively, prompted this investigation into the mechanism of action of this class of compounds to enhance their therapeutic efficacy. The locus of H2O2 production within the trypanosome was examined using cell-free homogenates. Experiments described herein suggest that H2O2 is formed by the alpha-glycerol phosphate dehydrogenase in an adventitious manner, and that no enzymatic means of disposing of this potentially toxic compound are present with the organisms. Naphthoquinones were found to substantially increase the rate of both oxygen consumption and H2O2 production by trypanosomal mitochondrial preparations. Presumably, the naphthoquinones are acting as coenzyme Q analogues. The addition of sublytic concentrations of both naphthoquinones and heme leads to a synergistic lysis of the organisms in vitro. Another approach to increasing the susceptibility of T. b. brucei to free radical damage involved reduction of the intracellular concentration of glutathione. This was accomplished through the use of trypanocidal arsenicals. Melarsenoxide and heme acted synergistically in vitro, an effect which was further enhanced via addition of a naphthoquinone. Moreover, hematoporphyrin D and tryparsamide were shown to have a synergistic effect in T. b. brucei-infected mice.


Inhibition of human erythropoietic colony formation in culture by treatment with Ia antisera.

Incubation with Ia antiserum, followed by complement, markedly inhibited erythroid colonies arising from hematopoietic cells present in the nonadherent low density fractions of normal bone marrow. Both erythropoietin-dependent colonies and bursts were eliminated at dilutions of antiserum equivalent to, or greater than the dilutions required to abolish the granulocyte-macrophage colony formation. The inhibitory effect of the Ia antiserum was abolished by absorption with B but not T cells from lymphoid lines. Available evidence suggested that Ia determinants are expressed on the erythropoietin-sensitive progenitors of the erythroid series in precise analogy to their sequence of expression on the granulocyte lineage. In both lineages, as shown previously, the Ia determinants become undetectable during subsequent stages of differentiation.


Type-specific radioimmunoassays for the gp70s of mink cell focus-inducing murine leukemia viruses: expression of a cross-reacting antigen in cells infected with the Friend strain of the spleen focus-forming virus.

We have isolated the gp70 of a helper-independent strain of a Friend mink cell focus-inducing (MCF) virus, Fr-MCF-1. This recombinant virus, like the previously described AKR-MCF viruses, has been shown by both biological and biochemical means to be an envelope gene recombinant between Friend murine leukemia virus (F-MuLV) and a mouse xenotropic virus. Utilizing (125)I- labeled Fr-MCF-1 gp70 and antiserum prepared against an MCF strain of Moloney type-C virus (Mol-MCF(83)), we have developed a radioimmunoassay which detects immunological determinant (s)contained in the gp70s of MCF viruses derived from F-MuLV, Mol-MuLV, and AKR-MuLV. This MCF determinant(s) is not detected in the ecotropic parents of each of these MCF viruses, nor in helper-independent murine xenotropic viruses derived from Swiss or BALB/c mice. A protein partially cross-reactive with the MCF gp70 determinant(s) is detected in a replicating xenotropic virus derived from NZB mice. Utilizing this MCF gp70 specific immunoassay, we can detect a cross-reacting gene product coded for by the Friend strain of the spleen focus-forming virus (SFFV) in rat fibroblasts nonproductively infected with SFFV. The results support earlier molecular hybridization studies which indicated that the genome of SFFV contains genetic information derived from both F-MuLV and xenotropic virus, and that the xenotropic-related sequences in SFFV are highly related to those found in MCF murine type-C viruses.


Comparison of wild-type and subacute sclerosing panencephalitis strains of measles virus. Neurovirulence in ferrets and biological properties in cell cultures.

The neurovirulence of two wild type (wt) and seven Subacute Sclerosing Panencephalitis (SSPE) measles virus strains was tested in young adult ferrets by intracerebral (IC) inoculation of infected Vero cell suspensions. Wt strains Edmonston and Woodfolk and SSPE strains Mantooth, Halle, and LEC-S did not produce a detectable encephalitis in the ferrets, but caused a significant formation of serum antibodies against measles virus. SSPE strains LEC, IP-3, Biken, and D.R., on the other hand, were all neurovirulent in ferrets, particularly strain D.R. which caused an acute encephalitis in all inoculated animals. Strain Biken was of particular interest since it caused a subacute encephalitis in four of seven ferrets. The subacute encephalitis was characterized by a long incubation time, persistence of virus in the brain for at least 8 mo, widespread inflammatory lesions, and production of measles virus specific IgG in the brain. A study of the biological properties of the various measles virus strains showed that wt strains Edmonston and Woodfolk and SSPE strains Mantooth, Halle, and LEC-S produced free virus particles in significant titers both in Vero and ferret brain (FB) cultures. Cytopathic effect (CPE) with cell-fusion was marked in Vero cultures, whereas only minimal CPE and no cell-fusion were observed in the FB cultures. SSPE strains LEC, IP-3, Biken, and D.R., on the other hand, were mostly cell-associated in Vero and FB cultures, although atypical cell-free particles were produced by strains Biken and IP-3. All four strains showed cell-fusing activity in FB cultures, particularly strain D.R., which was the only strain that spread more actively by fusion in FB than in Vero cultures. The results are discussed in relation to the neurovirulence of the various measles virus strains in adult ferrets. Pronounced cell-fusing activity in FB cells and cell-association with minimal or no production of cell-free virus seem to be essential to establish a brain infection in the animals.


Association of low C2 and C4 serum levels with the HLA-DW2 allele in healthy individuals.

HLA typed unrelated healthy individuals (HLA-DW2 positive n = 64, and HLA-DW2 negative n = 72) were investigated for their C2 functional activity and C4 serum protein levels. For the C2 and C4 levels a bimodal distribution was found in HLA-DW2 positive and HLA-DW2 negative individuals. HLA-DW2 positive persons had a significantly higher incidence of low C2 and C4 serum levels. Our data support the concept that genes governing C2 as well as C4 serum levels are in linkage disequilibrium with the HLA-DW2 allele of the major histocompatibility complex.


Thromboxane generation by human peripheral blood polymorphonuclear leukocytes.

Human peripheral blood polymorphonuclear leukocytes were stimulated to generate thromboxane B2 in a time- and concentration-dependent fashion upon exposure to serum-treated zymosan particles. Conversion by stimulated PMN of [14C] arachidonic acid to [14C]thromboxane B2 was confirmed by thin-layer radiochromatography, radio-gas chromatography, and mass spectrometry. Generation of thromboxane B2 was independent of platelet contamination and could be inhibited by the cyclooxygenase inhibitor, indomethacin. Cells rendered incapable of ingesting particles by treatment with cytochalasin B generated comparable amounts of thromboxane B2. These results suggest that human peripheral blood polymorphonuclear leukocytes synthesize thromboxanes in response to surface stimulation independently of phagocytosis.


Abelson virus-induced lymphomagenesis in mice.

The salient facts which have emerged from our study of Abelson virus (MuLV-A)lymphomagenesis in mice are that lymphoma induction is (a) age dependent, (b) virus dose dependent, and (c) under the control of host genes unrelated to other genes known to control murine leukemia (e.g., Fv-1 on Fv-2). Of 16 strains tested, only BALB/c and some of its derivative strains showed high sensitivity. Studies from CXB recombinant inbred strains and hybrids between them are interpreted to indicate that BALB/c carries dominant sensitivity alleles at two loci, tentatively designated Av-1 and Av-2, which conferon these mice partial susceptibility to MuLV-A lymphoma induction. In addition, H-2 may play a minor role in determining the susceptibility of mice to MuLV-A, its effect being seen only in mice homozygous for resistance at both Av-1 and Av-2. Virologic studies indicate that the resistance of adult B6 mice is not related to restriction on the helper virus replication, but is specific for the defective transforming virus genome.


A macrophage tumor cell line and plasminogen activator. A potential model system for macrophage regulation of enzyme production.

The macrophage cell line, RAW264.10, synthesizes and secretes plasminogen activator. Production of this enzyme is inhibited by low concentrations of glucocorticoids and increased by phorbol myristate acetate. It is proposed that this line could be a suitable model for the regulation of enzyme synthesis by mouse peritoneal macrophages.


The first component of complement. A quantitative comparison of its biosynthesis in culture by human epithelial and mesenchymal cells.

Epithelial and mesenchymal cells synthesized and secreted all three subcomponents of the first component of complement (C1): C1q, C1r, and C1s. Quantitatively, however, columnar and transitional epithelial cells secreted 400--3,700 times more hemolytically active C1 than monocytes or fibroblasts. Only columnar epithelial cells synthesized C1 subcomponents with subunit structures similar to their serum counterparts. Transitional epithelial cells, fibroblasts, and monocytes produced C1q and C1s with subunits of apparent molecular weights larger than reported values. C1r from all cell lines was physiochemically similar to serum C1r.


Degradation of serum amyloid A protein by surface-associated enzymes of human blood monocytes.

Peripheral blood monocytes incubated in a serum-free medium degraded serum amyloid A (SAA) protein along three pathways. Of 20 normal subjects, 8 degraded SAA completely with no detectable intermediates. Eight subjects transiently produced an amyloid A (AA)-like intermediate which comigrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) with tissue AA protein and reacted with antisera to AA, whereas four subjects yielded a persistent AA-like intermediate on PAGE. This group also failed to degrade tissue AA protein. Cells from 10 patients with amyloidosis fell into the second group. The responsible enzymes appear to be serine proteases because they are inhibited by disopropyl fluorophosphate. They were not affected by epsilon-amino caproic acid, L-1-tosylamide-2-phenylethyl chloromethyl ketone, or N-alpha-p-tosyl-L-lysine chlormethyl ketone. It appears possible that the enzymes are associated with the outer membrane of the cell because only a small fraction of the activity is secreted into the medium and because enzyme activity remains after fixation of the cells with glutaraldehyde which completely stops phagocytosis. Perhaps differences in patterns of proteolysis may play a role in the predisposition to amyloidosis.


Human C4-binding protein. II. Role in proteolysis of C4b by C3b-inactivator.

We recently described the isolation from human serum of a high molecular weight protein with specific binding affinity for fluid-phase activated C4. We show here that the C4-binding protein (C4-Bp) functions as an essential cofactor in the proteolysis of C4b in the presence of C3b-inactivator (C3bINA). C4-bp, together with C3bINA, cleave the alpha'-chain of C4b into three fragments called alpha2, alpha3, and alpha4, with mol wt of 47,000, 25,000, and 17,000 daltons, respectively. The alpha2 fragment was dissociated from C4b without reduction, whereas the alpha3 and alpha4 fragments were disulfide bonded the other chains of C4b. The reaction did not occur when either C4-bp or C3bINA were omitted, nor in the presence of either protein in combination with beta1H. Native C4 was not affected by C3bINA aand C4-bp. C4b was not cleaved when incubated in serum of a patient with genetic deficiency of C3bINA. However, when purified C3bINA was added, the alpha'-chain of C4b was cleaved and fragments with the same molecular weight as alpha2, alpha3, and alpha4 were generated.


Suppression of the immune response in C3H/HeJ mice by protein-free lipopolysaccharides.

The experiments described herein demonstrate the plaque-forming cell response of C3H/HeJ mice can be suppressed by a Boivin type lipopolysaccharide (LPS) and a deproteinized glycolipid. Suppression was observed both in vivo and in vitro, and could be transferred to normal cells in coculture experiments. This newly discovered effect of LPS in C3H/HeJ mice indicates that the adjuvant and inhibitory action of LPS may be distinct phenomena which are under different genetic regulation. Thus, the C3H/HeJ strain provides a convenient animal model for study of immunosuppression independent of the adjuvant effect.


Increased sialylation of surface glycopeptides of human trophoblast compared with fetal cells from the same conceptus.

The surface glycopeptides of human trophoblastic cells have been compared with those of fetal cells from the same embryos using double-labeling methods with isotopes of L-fucose and D-glucosamine. A faster eluting, neuraminidase-sensitive, fraction was observed on Sephadex chromatography of the trophoblast spectra when D-glucosamine was used as precursor. Labeling with fucose did not appear to result in any differences, thus suggesting that the glycopeptides characertistic of trophoblast contained glucosamine-derived metabolic products, including sialic acid, but excluding fucose. This increased sialylation is similar to, but not identical with, modifications observed in neoplastic cells, and on this basis it is postulated that two species of glycopeptides may be involved in atypical cellular behavior. The first contains sialic acid and other sugars excluding fucose, and is associated with localized cellular growth and invasion. The second contains both sialic acid and fucose and is characteristic of neoplastic cells.


Protein kinase activity associated with the surface of guinea pig macrophages.

Protein kinase activity has been detected associated with the outer surface of guinea pig peritoneal macrophages. Macrophages incubated with [gamma-32P]ATP incorporated 32P-phosphate into cell-associated proteins. Inorganic phosphate did not compete, nor could inorganic [32P]phosphate substitute as the phosphate donor, demonstrating that transfer of phosphate from ATP to protein is direct and extracellular. The macrophage-associated protein kinase was also shown to phosphorylate added acceptor protein (histone) and to be tightly associated with the cell surface. Thus, a new ectoenzyme, a protein kinase, has been detected in macrophages.


The effect of complement on the ingestion of soluble antigen-antibody complexes and IgM aggregates by mouse peritoneal macrophages.

Complement was found to stimulate markedly the ingestion of soluble antigen-antibody complexes by mouse peritoneal macrophages. This was shown indirectly by measuring the release of degradation products when the complexes were labeled with 125I, or directly when the antigen, that was human transferrin, was labeled with 59Fe. In this case, the metal which was released from human transferrin inside the cells was not excreted, and its accumulation in the macrophages was a direct index of the uptake of immune complexes. The decay of radioactivity in macrophages after ingestion of 125I-labeled complexes was similar when they were taken up with or without complement, indicating that complement acts primarily on ingestion and not on digestion or excretion. The ingestion of complexes was morphologically confirmed using fluorescein-labeled antigen in the immune complexes. The opsonic effect of complement was also observed with IgM aggregates indicating that soluble complexes can be ingested through complement receptors without involvement of Fc-receptors, as required for particulate antigen-antibody complexes.


Activation of measles virus from silently infected human lymphocytes.

Lymphocytes were incubated with measles virus for 4 days in the absence of a lymphocyte stimulating agent. Such nonstimulated lymphocytes, infected with measles virus, did not express the virus antigens that are detectable by cytotoxic antibodies. Approximately 1 out of 5,000, or even fewer, of such lymphocytes produced virus as demonstrated by the infectious center assay; in the supernate only 10--100 infectious viruses per milliliter were detected. No virus structures could be observed by means of an electron microscope. However, such lymphocytes showed no reaction to phytohemagglutinin (PHA) in terms of DNA synthesis in a subsequent culture in the presence of antibodies against measles to prevent spreading of the infection to other cells. Although stimulation by PHA did not result in a significant increase in [3H]thymidine incorporation, measles virus was activated; 32 h after the addition of PHA nearly 80% of the cells were killed by measles virus antibodies and complement. The number of virus-producing cells increased to approximately 1 in 300 or more, and at 72 h the virus titer in the supernate had risen to 10(6) infectious particles per ml. This reactivation of measles virus was still obtained when PHA was added as late as 8 or more days after the initial infection.


The Qa-1 antigenic system. Relation of Qa-1 phenotypes to lymphocyte sets, mitogen responses, and immune functions.

The antiserum (B6 X A-Tlab) anti-A (Tlaa) defines several TL antigens expressed exclusively on thymocytes. When reacted with peripheral lymphocytes, the same antiserum defines another antigenic system, provisionally termed Qa-1. The genotypic disparity distinguishing the recipients and donors in this immunization comprises a section of chromosome 17 extending from a crossover point between H-2D and Tla to a presently unmarked point beyond Tla. Therefore although Qa-1 may constitute a single cell surface component, it is equally probable that the Qa-1 system defines two or more cell surface components determined by genes in this region, each of which may be expressed on a different cell set. Cytotoxicity assays indicate that Qa-1 antigen is expressed on Lyt-1 cells and Lyt-123 cells, and may serve to subclassify these two cell sets; it is not known whether Qa-1+ cells may occur within the small Lyt-23 set. There may be also be a cell set with the phenotype Thy-1--:Qa-1+. Another distinctive feature of the Qa-1 system is the characteristic profile of responses to mitogens exhibited by spleen cell populations from which Qa-1+ cells have been eliminated; in conventional assay of [3H]thymidine incorporation the response to lipopolysaccharide was essentially unchanged, the response to phytohemagglutinin M (PHA-M) was virtually abolished, and the response to concanavalin A (Con A) was reduced by 40%. The third distinctive feature of the Qa-1 system is the characteristic profile of changes which elimination of Qa-1+ cells produces in tests of immune function in vitro: (a) proliferation, measured by [3H]thymidine incorporation, in mixed lymphocyte culture (MLC) with major histocompatibility complex (MHC)-incompatible stimulator cells, was not affected. (b) in tests of cell-mediated cytotoxicity (CMC) of MHC-incompatible target cells, neither the generation nor the effector functions of cytotoxic lymphocytes was affected, implying that Lyt-23 prekiller and killer cells are Qa-1--. (c) primary and secondary responses to SRBC were considerably augmented, suggesting that Qa-1+ cells may be responsible for suppression in this test system. (d) accordingly the suppression of the anti-sheep erythrocyte (SRBC) response normally engendered in spleen cells by culture with SRBC was profoundly reduced by elimination of Qa-1+ cells, either before or after culture. (e) the suppression of the anti-SRBC response normally engendered in spleen cells cultured with Con A was reduced by removal of Qa-1+ cells before but not after culture with Con A. Although analysis is as yet far from complete, the Qa-1 system should already be of considerable value because it distinguishes a population of lymphocytes that is not defined by any other antigenic system, according to three criteria: (a) representation of Qa-1 cells among T-cell sets defined by Lyt phenotypes, (b) the profile of responses to mitogens exhibited by lymphocyte populations depleted of Qa-1+ cells, and (c) the profile of immune responses of lymphocyte populations depleted of Qa-1+ cells.


Alteration of clonal profile. I. Effect of sublethal irradiation on the responses to phosphorylcholine in BALB/c mice.

BALB/c mice exhibit greater than 90% H8 clonal dominance in the immune response to phosphorylcholine. Adult mice exposed to 500 rads were initally unable to produce a humoral immune response to both phosphorylcholine and trinitrophenol antigens, and the direct plaque-forming cell response was slowly regained over several weeks. Clonotypic analysis wity antisera directed against the H8 idiotype showed that the H8 clone initially dominated the recovery of the response to phosphorycholine but that 60 days after the irradiation significant numbers of non-H8 clones could be detected. This same pattern could be seen in mice irradiated with 100 rads, a dose that does not completely abrogate the H8 response to phosphorylcholine. Sublethal irradiation of neonates before they had acquired responsiveness to phosphorylcholine could also eventually lead to the emergence of non-H8 idiotypes. Thus, a radiosensitive element regulates the expression of clonal dominance in anti-phosphorylcholine responses of BALB/c mice.


Three approaches to the recognition of affective disorders in family practice: clinical, pharmacological, and self-rating scales.

No single approach to the recognition of affective disorders worked in a ten percent sample of a family practice population, screened in the summer of 1975. Among 298 adults followed prospectively for two years, about six percent developed an affective disorder (3.8 percent anxiety, 1.9 percent depression, and 0.4 percent episodes of both). The sex ratio was predominantly female (2.7:1). Most of the cases were recognized by clinical problem lists, but 23 percent of the cases would have been missed without a computerized search of prescribed drug profiles. Self-rating tests (Zung for depression and Reeder for anxiety) performed poorly at predicting cases prospectively, and unimpressively in retrospect. The burden of these disorders is considerable, with a prevalence in this population of at least 19 percent. Of these cases, 22 percent had "mixed" episodes of depression, anxiety, and combinations seen at various visits. Criteria for diagnosis need to be clarified for more precise diagnosis, proper medication, as well as better estimates of incidence and patient load.


Exploring the doctor-patient relationship: a sociocultural pilot study in a family practice residency.

Family physicians' growing attention to the nature of their patients' live should include the social and cultural factors that influence patient health and illness behavior. Patient visits to a family practice residency program were found to be influenced by the patients' beliefs about symptoms and the beliefs of their significant others, and symptom interference with valued activities. Data from physician-patient encounters suggest that physician attention to such sociocultural information as occupation and family structure may have positively influenced rapport. Results from this pilot study confirm the feasibility of observational research by physician-behavioral scientist teams in a primary care setting.


Obstetrics in family practice: a model for residency training.

Family physicians have a unique service to offer families at the time of their reproduction, and have a role to play that cannot be duplicated by an obstetrician-gynecologist or pediatrician. The process of a family integrating a new member is a natural concept to family practice and lends itself to a family-centered model of care seldom seen in medicine. Practicing obstetrics has a positive effect on a family physician's practice for without obstetrics a practice largely of episodic adult internal medicine develops. Obstetrical care provided by a family physician is a natural answer to the currently articulated public need for personalized, sensitive, family-centered, and expert childbirth care. Obstetrical training in the family practice residency needs to include a longitudinal pregnancy care experience in addition to block rotation on hospital services to teach residents skills of good obstetrical practice and to develop an attitude of family-centered health-care advocacy. A detailed program of family-centered patient education classes practical for a private group practice has been developed to extend throughout the entire course of pregnancy and includes classes after delivery.


A required program in geriatrics for medical students.

Very few medical schools in the United States have compulsory training in geriatrics for medical students. A program has been developed in the Department of Family Practice at Southern Illinois UniversitySchool of Medicine. This has become a required component of the undergraduate family practice clerkship. The initial format is described together with changes which occurred as result of student, faculty, and patient feedback, practical problems encountered in conducting the program, and changes in educational goals.


Attitudes and patterns of practice: a comparison of graduates of a residency program in family medicine and controls.

Two groups of graduates of the University of Western Ontario Faculty of Medicine were compared. The study group had satisfactorily completed a two-year residency program in family medicine at the University, commencing at graduation from medical school; the controls had completed a one-year internship after graduation, but had not pursued specific residency training in family medicine. Both groups were engaged in family practice in Ontario at the time of the study. As predicted, the groups differed in their attitudes; the graduates were more satisfied with practice than the controls and placed more importance on emotional factors in illness. Anticipated differences in patterns of care provided were also found. Family medicine graduates of conducted proportionately more noninstitutional care. The findings were not generalized beyond the one program. The advantages and limitations of program evaluation through studies of graduates are discussed.


Toward the evaluation of family practice: development of a family utilization index.

This paper describes a research project that establishes criteria for utilization patterns of a family practice that could be used to develop evaluation techniques for family practice as a method of delivering primary medical care. The criteria are summarized in a Family Utilization Index,  which measures the utilization patterns of a family unit. Changes in the Utilization Index are compared over a five-year period. Changes in attitudes and opinions about family practice in general and the specific Family Medicine Clinic are also compared over time and related to changes in the Family Utilization Index. Utilization patterns have significantly shifted over a five-year period, with more total visits to the clinic due to an increase in the number of family members per family unit using the clinic. Both the utilization patterns and attitudes toward the role of the family physician have shifted, indicating an increased acceptance of family practice.


Nuclear transplantation in Bombina orientalis and utilization of the Pale mutation as a nuclear marker.

The discoglossid frog, Bombina orientalis, displays many characteristics that make it desirable as a laboratory animal. We report here the first successful transplantation of embryonic nuclei into enucleated eggs of this organism. The participation of the grafted nucleus in the development of the transplant embryos was confirmed with the use of a genetic marker, the Pale mutation. Frogs homozygous for this recessive gene are much lighter in appearance than the wild-type animals. The use of this trait in appropriate experiments demonstrated that nuclear transplantation in B. orientalis provides embryos whose nuclei may be reliably interpreted as being derived from the injected nucleus.


Breakdown of the germinal vesicle in bovine oocytes cultivated in vitro.

Breakdown of the germinal vesicle (GV) was studied in bovine follicular oocytes cultivated in vitro. The intact GV of control oocytes did not correspond to the findings in porcine oocytes (GV I). Instead it was characterized by a nuclear membrane and a few chromocenters in finely granular nucleoplasm (GV II). After two and three hours of cultivation, GV III predominated (50% and 64% respectively). Faintly-staining chromatin and after a longer interval in the form of filaments also appeared round the chromocenters. After four hours, 35.8% of the oocytes were still at stage GV III but the GV of 46.6% of the oocytes already contained filamentous bivalents (GV IV). After five hours, GV IV (59.7%) was typical, with a less distinct nuclear membrane and condensing bivalents. GV breakdown was completed in 30.4% of the oocytes after five hours of cultivation and in 92.5% after six hours.


Testosterone and 5alpha-dihydrotestosterone inhibit both growth and spermatogenesis in the remaining testis in partially castrated adult newts, Notophthalmus viridescens.

The testis of the newt, Notophthalmus viridescens, undergoes hypertrophy following partial castration. Injections of either testosterone or 5alpha-dihydrotestosterone are equally effective in inhibiting the increase in testis weight which follows partial castration. In addition, both of these androgens inhibit spermatogenesis, i.e., spermatogonia appear to be inhibited resulting in early cessation of spermatogenesis and a precocious division of the testis into separate spermatogonia and sperm compartments.


Temperature dependence of sperm-egg fusion and post-fusion events in hamster fertilization.

The effects of temperature (4--37 degrees C) on sperm-egg fusion and the post-fusion events were studied. At 4--10 degrees C, acrosome-reacted spermatozoa bound to egg plasma membranes, but could not fuse with them. At 25 degrees C or above, both binding and fusion took place. The post-fusion events could occur over a broad temperature range (4--37 degrees C) but the events progressed faster with increasing temperature. An abnormal development of egg pronucleus, possibly due to an incomplete functioning of the meiotic spindle mechanism, was observed in eggs inseminated at 37 degrees C and cultured at 25 degrees C.


Increase in concanavalin A binding sites in mouse blastocysts during implantation.

The number of concanavalin A (Con A) binding sites were determined in mouse blastocysts before and during implantation. In intact pregnant mice (Day 1 = day of finding vaginal plug), the Con A binding sites per blastocyst were increased from 169 million on Day 4 morning to 1160 million on Day 5 morning when implantation was under way. In pregnant mice ovariectomized on Day 3 and treated daily with 1 mg progesterone, the Con A binding sites per blastocyst on Day 9 (inactive) were 363 million; if the mice had received an additional injection of estradiol 24 hours earlier to induce implantation, the Con A binding sites were increased to 1211 millions. Thus, a more than twofold increase in the Con A binding sites occurs in the mouse blastocyst during implantation.


Apparent trophoblast giant cell production in vitro by core cells isolated from cultured mouse inner cell masses.

Mouse ICM's that were isolated from blastocysts by immunosurgery and subsequently cultured for four to five days were tested for their ability to form trophoblast giant cells (TGC's) in vitro. The cores were isolated from such ICM's by a second immunosurgery and cultured for 7 to 14 days. After two days of culture a variable percentage (30%--90%) of the ICM cores produced outgrowths containing cells that resembled those of cultured ectoplacental cone. Then the outgrowths became amitotic and produced vascuolated cells that enlarged to dimensions of 200 X 375 micrometer with nuclei as large as 53 micrometer in diameter. The time course of their development from the ICM cores, their morphology and their nuclear diameters suggest that these large cells were TGC's.


The effect of oxygen on the development of preimplantation mouse embryos in vitro.

The optimal oxygen tension for development of preimplantation mouse embryos to the blastocyst stage in vitro was found to be between 2.5% and 5%. One- and two-cell embryos had a more sharply defined range of oxygen tension capable of supporting development than 8-cell and morula stages. At all stages of development, more embryos developed to the blastocyst stage under 5% O2 compared to the numbers of developing under higher oxygen tensions (20% and 40% O2). The blastocysts developing under 20% O2 had fewer blastomeres than those which developed under 5% O2. As the time required for development to the blastocyst stage in vitro increased, there were fewer blastomeres present at the blastocyst stage. These results indicate that the cleaving mouse embryo has an optimal oxygen requirement in vitro of about 5%. At higher oxygen tensions, fewer embryos develop to the blastocyst stage and in those which do develop, there are fewer cell divisions. If a gradient of oxygen tension exists across the blastomeres from the outside of the embryo to its centre, the blastomeres might be using this gradient to obtain imformation about their location within the embryo and respond accordingly. Thus blastomeres on the outside at a higher oxygen tension would divide at a slower rate and form trophectoderm whereas those on the inside at a lower oxygen tension would divide more rapidly and contribute to the inner cell mass.


Mitochondria and other calcium buffers of squid axon studied in situ.

Continuous nondestructive monitoring of intracellular ionized calcium in isolated squid axons by differential absorption spectroscopy (using arsenazo III and antipyrylazo III) was used to study uptake of calcium by carbonyl cyanide, p-trifluoromethoxy-phenylhydrazone (FCCP)- and (or) cyanide (CN)-sensitive and insensitive constituents of axoplasm. Known calcium loads imposed on the axon by stimulation produced proportional increments of free axoplasmic calcium. Measurement of increments in ionized calcium as a function of load confirmed earlier reports of buffering in normal and FCCP- and (or) CN-poisoned axons. Measurement of rates of calcium uptake by presumed mitochondria showed little uptake at ambient Ca below 200--400 nM, with sigmoidal rise to about 20--30 mumol/kg axoplasm per min (calculated to be about 200 mmol/kg mitochondrial protein per min) at 50 micrometer, indicating a functional threshold for presumed mitochondrial uptake well above physiological ionized calcium concentration. Treatment of stimulated axons with cyanide, to release calcium from presumed mitochondria, showed that the sensitivity to cyanide decreased progressively with time after stimulation (t 1/2 = 3--10 min) implying transfer of sequestered calcium into a less metabolically labile form.


Calcium buffering in presynaptic nerve terminals. II. Kinetic properties of the nonmitochondrial Ca sequestration mechanism.

The kinetic properties of the nonmitochondrial ATP-dependent Ca sequestering mechanism in disrupted nerve terminal (synaptosome) preparations have been investigated with radioactive tracer techniques; all solutions contained DNP, NaN3, and oligomycin, to block mitochondrial Ca uptake. The apparent half-saturation constant, KCa, for the nonmitochondrial Ca uptake is approximately 0.4 micrometer Ca; the Hill coefficient is approximately 1.6. Mg is also required for the Ca uptake, and the apparent KMg is approximately 80 micrometer. ATP and deoxy-ATP, but not CTP, GTP, ITP, UTP, ADP, or cyclic AMP, promote Ca uptake; the KATP, is approximately 10 micrometer. ATP analogs with blocked gamma-phosphate groups are unable to replace ATP. Particulate fractions from the disrupted synaptosomes possess Ca-dependent ATPase activity in the presence of Mg; the apparent KCa for this activity is 0.4--0.8 micrometer Ca, and the Hill coefficient is approximately 1.6. The Ca uptake and ATPase kinetic data suggest that the hydrolysis of 1 ATP may energize the transport of two Ca2+ ions into the storage vesicles. The second part of the article concerns the intraterminal distribution of Ca in "intact" terminals. When the terminals are disrupted after 45Ca loading, about one-half of the 45Ca is retained in the particulate material; some of this Ca, presumably stored in mitochondria, is released by the uncoupler, FCCP. Some of the 45Ca is released by A-23187, but not by FCCP; this fraction may be Ca stored in the nonmitochondrial sites described above. The proportion of 45Ca stored in the nonmitochondrial sites is increased when the Ca load is reduced or when the mitochondria are blocked with ruthenium red. These data indicate that the nonmitochondrial Ca storage sites are involved in intraterminal Ca buffering; they may play an important role in synaptic facilitation and post-tetanic potentiation, which result from Ca retention after neural activity.


Nexal membrane permeability to anions.

The permeability of the septa of the earthworm in the median axon has been calculated for the anions fluorescein and its halogen derivatives. The values ranged from 5.4 X 10(-5) to 4 X 10(-6) cm/s. Previously, the septa had been shown to contain nexuses. By using freeze-fracture material, the surface area of nexus on the septal membranes was determined to be 4.5%, very similar to the percentage of nexus in the intercalated disk of mammalian myocardium. Plasma membrane permeability to these dyes was also calculated and shown to be much less than that of the septal membranes. In addition, an estimate of cytoplasmic binding for each dye was made, and most dyes showed little or no binding with the exception of aminofluorescein.


Anion inhibitor-sensitive unidirectional sodium movements in the human erythrocyte.

The increased unidirectional sodium influx found when human erythrocytes are suspended in isotonic salt solutions containing bicarbonate ions as a replacement for chloride ions was examined. The increased sodium movement appears to have the transport characteristics of anion movement. Inhibitors of anion transport such as furosemide, fluorodinitrobenzene (FDNB), and 4-acetamido-4'-isothiocyano-stilbene-2-2'-disulfonic acid (SITS) drastically inhibit these augmented sodium movements. An ion-pair mechanism appears to phenomenologically describe much of the data. A possible role for carbamino groups is considered. Such a model, however, required additional assumptions to explain the selectivity and the anion inhibitor effects.


Cation selectivity of the apical membrane of the turtle colon: sodium entry in the presence of lithium.

Exposure of the apical surface of the isolated turtle colon to Li produced a marked transient in short-circuit current (ISC) and total tissue conductance (GT) which was abolished by amiloride but was unaffected by ouabain or by removing Na or Cl from the mucosal bathing solution. Despite marked changes in Isc, Na uptake across the apical membrane was a linear function of time during exposure to Li-containing solutions, and except at very high Li concentrations, the initial rate of Na uptake, JiNa, was identical to its pre-Li value. In the presence of Li, however, JiNa was significantly less than the total Isc. The apparent "transference number" for Na in the apical membranes was a function of the Li:Na concentration ratio in the mucosal bathing solution. These results suggest that Li can carry substantial amounts of current through amiloride-sensitive channels in the apical membrane of the colon without having any effect on the rate coefficient for Na entry. This behavior is not consistent with "competition" of Na and Li for a membrane "carrier" but rather suggests that the Na entry mechanism may be a population of pores or channels through which Na and Li may pass with negligible interaction.


Effects of veratridine on Ca fluxes and the release of oxytocin and vasopressin from the isolated rat neurohypophysis.

Uptake of radioactive calcium, 45Ca efflux, and hormone release from the isolated rat neurohypophysis were monitored in vitro after the addition of veratridine to the incubation medium. Veratridine dramatically increased hormone release, but the release was not sustained and had declined by about 90% after 2 h. Removal of external Na+ prevented hormone release as did addition to the incubation medium of tetrodotoxin or the calcium antagonists D600 and Mn2+ ions. Veratridine increased 45Ca uptake into the isolated neurohypophysis and the increase could be prevented by addition of tetrodotoxin or D600 to the medium. Efflux of 45Ca was not changed by addition of veratridine. The results underline the importance of both Na+ and Ca+2 channels in the regulation of secretion of neurosecretory products.


Intracellular characteristics and responses of taste bud and lingual cells of the mudpuppy.

Intracellular recordings of membrane potentials of mudpuppy lingual cells were made with micropipette electrodes. Three types of cells were distinguished by their responses to chemical stimulation. Surface epithelial (SE) cells outside of taste buds responded with large membrane potential and resistance changes to a variety of stimuli representing the four taste qualities. Salts and acids evoked particularly large potential changes, and MgCl2, acids, and quinine greatly increased the membrane resistance. One type of taste bud cell (TB-1) was characterized by large depolarizations to K salts, and the other type of taste bud cell (TB-2) characteristically hyperpolarized to MgCl2, acid, and sugar solutions. Membrane resistance changes accompanying TB-1 and TB-2 cell responses were relatively small compared to those of SE cells. Electrotonic coupling was observed between pairs of SE and TB-2 cells but not for pairs of TB-1 cells nor cells of different types. After recording cell responses, dye-marking allowed verification of results in situ and histologically. From the identification of cells in section, it is hypothesized the TB-1 and TB-2 cells correspond to light and dark cells, respectively. Responses of TB-1 cells imply a taste receptive function; wheras TB 2-cell responses suggest secretory, supportive, and (or) receptive functions. Factors affecting cellular characteristics, non-taste  bud cell responsiveness, response mechanisms, and function of electrotonic coupling are discussed in relation to taste reception.


Differences in cellular contractile protein contents among porcine smooth muscles: evidence for variation in the contractile system.

Cellular myosin, actin, and tropomyosin contents and ratios were determined for arterial (carotid, aorta, and coronary), intestinal (circular and longitudinal), esophageal, uterine, and tracheal smooth muscles inthe pig. Tissue protein contents were estimated by densitometry of polyacrylamide gels after electrophoresis of sodium dodecyl sulfate-treated tissue homogenates. Cellular contractile protein contents were estimated by correction for extracellular spaces. Cellular myosin contents were similar in each tissue (average +/- 1 SEM = 19.6 +/- 0.8 mg/g cell wet wt). However, the cellular contents of the thin filament proteins, actin and tropomyosin, were significantly higher in the arteries than in the nonarterial tissues. The calculated weight ratios of actin: myosin averaged 2.6 +/- 0.2 in the three arterial tissues and 1.5 +/- 0.1 in the nonarterial tissues, which may be compared with 0.36 in vertebrate striated muscles. The actin:tropomyosin weight ratios for all tissues were 3.7 +/- 0.1,  a value comparable to the skeletal muscle ratio. The physiological implications of variations in the cellular thin filament protein contents are unknown, but these variations probably contribute to the observed differences in contractile function among various smooth muscles.


Interaction of external alkali metal ions with the Na-K pump of human erythrocytes: a comparison of their effects on activation of the pump and on the rate of ouabain binding.

The effects of external alkali metal ions on the rate of ouabain binding and on the rate of the Na-K pump were examined in human red blood cells. In Na-containing solutions, K, Cs, and Li decreased the rate of ouabain binding. For K and Cs, the kinetics of this effect were similar to those for their activation of the pump. In Na-free (choline-substituted) solutions the rate of ouabain binding was decreased by K whereas it was promoted by Cs and Li. External Na increased the rate of ouabain binding whether or not external K was present, and the kinetics of this effect were not the same as those for inhibition of the pump by Na. These findings are interpreted to mean that not only do the cations affect ouabain binding at the external loading sites on the pump from which ions are translocated inward, but that there are additional sites on the external aspect of the pump at which cations can promote ouabain binding, and that these sites can be occupied by Li, Na, and Cs. It is postulated that these latter sites are those from which Na is discharged after outward translocation by the pump.


Differences in sialic acid content of human interferons.

Human leucocyte, lymphoblastoid and fibroblast interferons were separately treated with sialidase and the effect of this on their isoelectric focusing was examined using a system in which full dissociation of complexes occurred. Both leucocyte and lymphoblastoid interferons showed a single form with an isoelectric point which was unaltered by treatment with sialidase. In contrast, fibroblast interferon showed three forms which were reduced to one by treatment with the enzyme.


The ocr gene function of bacterial viruses T3 and T7 prevents host-controlled modification.

On pre-infection of the host Escherichia coli B with u.v.-inactivated T3 or T7 phage able to express their early genes (like 0.3), B-specific modification of superinfecting, successfully multiplying viruses does not take place. The ocr gene function (gene 0.3) of T3 and T7 not only prevents host-specific DNA restriction but also modification, probably by inhibiting the same late step in the interaction between the restriction enzyme and DNA.


Solid-phase radioimmunoassay determination of virus-specific IgM antibody levels in a follow-up patients with naturally acquired measles infections.

The question of the exact disappearance time or possible persistence of measles-specific IgM antibodies after naturally acquired measles virus infections was studied with a sensitive solid-phase radioimmunoassay (RIA) method. A total of 30 patients were analyzed with follow-up times varying from 4.5 to 8 months; all were measles IgM positive in the first serum specimen obtained after the onset of rash. In 29 of 30 patients, the measles IgM declined to undetectable levels by approximately 90 days. The remaining patient developed postmeasles encephalitis, however, and was found to have a prolonged measles IgM antibody response. For comparison, the measles-specific IgG response was also studied and was found to develop only slightly later than the IgM response, with levels then remaining high and stable up to 8 months later. Although apparent measles IgM antibodies were found in 1 of 64 nonmatched adult controls, they were due to the presence of high levels of IgM-class rheumatoid factor. The data presented indicate that measles IgM antibodies begin to decline soon after the onset of rash and reach negative levels 1 to 3 months later; in complicated infections, however, measles IgM antibody synthesis may not terminate normally.


Mother-stranger discrimination in three-month-old infants and subsequent Gesell performance.

The amount of vocalization, motor activity, and smiling in response to vocal stimulation by the mother and by a stranger was recorded from 14 normal male infants when they were 3, 5, 7, and 9 months old. The Gesell Developmental Schedules were administered to them at age 9 months. High Gesell developmental quotient infants showed different vocalization and motor activity responses to the mother versus the stranger as early as 3 months. These differences diminished progressively to a minimum at 9 months. Low Gesell developmental quotient infants showed no differential responses to mother versus stranger. The results suggest that mother-stranger discrimination at age 3 months may be used as an indicator of subsequent cognitive development, and further suggest that bright babies may attain permanence for the mother's schema as early as 3 months of age.


Comparison of normal and learning disabled children on a nonverbal short-term memory serial position task.

A serial recall task was used to compare performance of 15 normal and 15 learning disabled elementary school children matched on CA, IQ, and sex with two and three dimensional representations of nonverbal eight-point shapes. Two a priori assumptions were not supported: (a) no differences in recall were found between groups and (b) no differences in recall were found for either group using two or three dimensional stimuli. Three dimensional stimuli did facilitate visual rehearsal at the primacy position for both groups. Learning disabled children's performance was consistent with the mediation deficiency hypothesis found with normal children.


Delay of reinforcement effects with reflective and impulsive children.

Reflective, impulsive, fast-accurate, and slow-inaccurate second grade boys and girls (N = 156) learned a discrimination task with one of three reinforcement delay conditions: No delay; 10 sec delay with an attentional aid filling the delay period; and 10 sec delay with an unfilled interval. The attentional aid was expected to lead to improved learning task performance (vis-à-vis delay without an aid), especially for impulsive children who would focus on the task more with an aid during the delay. The results indicated that all children learned less well with a delay of feedback, and the attentional aid was ineffective (possibly because it did not prevent competing responses from occurring). The children who did best on the test of Conceptual Tempo (the MFF), the fast-accurates, learned with the fewest errors, while the slow-inaccurate children made the most errors in learning. The results did not support the contention that impulsive children are poor attenders, but did indicate that some components of Conceptual Tempo are related to discrimination learning.


Responses of boys and girls to aggressive, assertive, and passive behaviors of male and female characters.

Boys and girls in grades 4, 6, and 8 answered five questions after reading stories in which a male or female character behaved aggressively, assertively, or passively. As hypothesized, the results indicated differential degrees of approval for aggressive, assertive, and passive behavior depending upon the sex of the character engaged in the behavior. Boys and girls also responded in different ways to the three types of behavior. Developmental trends indicated an increasingly positive evaluation of the effectiveness of passive behavior by females and an increasingly negative evaluation by males with age. The implications for the acquisition of sex-stereotyped behavior patterns are discussed.


Successive visual discrimination of forms in 10-month-old infants.

The purpose of this research was to assess the infant's ability to make successive discriminations in the size of a figure. The Ss were 90 10-month-old infants who were habituated to a block figure and dishabituated on different subtle size transformations of that figure. Dishabituation data revealed that the infants were able to detect transformations which increased the area of the habituated figure by 7 percent. There was no evidence of a differentiated sensitivity to detect a change in any special location of the original figure.