The remodeling of the edentulous mandible.

In a sample of mandibles having complete or nearly complete loss of dentition, the left half of each mandible was serially sectioned. The entire perimeter of each section was analyzed for the distribution of resorptive and depository periosteal surfaces, and from this information, the fields of remodeling were mapped for the mandible as a whole. The most common patterns of combined resorption-deposition and the range of variations were then determined. The over-all distribution of remodeling fields in the edentulous mandible differs markedly from that in the young, growing mandible. In most of the edentulous specimens, the surface of the basal bone on both the medial and lateral sides of the corpus is of a depository nature. The overlying alveolar regions on both the lingual and buccal sides, however, are characteristically resorptive. Significantly, the placement of the reversal line between the alveolar resorptive and the basal depository areas is much lower (i.e., at the level of the mental foramen) on the buccal side. Except for its inferior part, the lateral side of the ramus tends to be largely resorptive in character, and the posterior half of the lingual side also tends to be resorptive. Unlike the child's mandible, the posterior border of the ramus is resorptive, and the posteroanterior dimension of the ramus (not the whole mandible) becomes reduced and narrowed in conjunction with resorption along the anterior border. However, the amount removed from the anterior ramus is actually added to the dimension of the corpus, which becomes longer. Further, removal from the posterior ramus border does not affect the over-all length of the mandible unless condylar reduction is also involved. Also, over-all arch length is not decreased, because the surface of the mental protuberance is retained as a depository type of field (or at least does not become actively resorptive). The corpus-ramus angle (not gonial angle) is increased in the antegonial region. Because of the opening of this angle, over-all mandibular length as well as arch length is increased. In about half of the specimens, arch width was not decreased, because the lateral side of the corpus is usually of a depository nature. Notching of the anterior side of the condylar neck and the inferior part of the anterior ramus border is associated with resorptive fields in these regions, changes that are presumed to be a consequence of pressure contacts made with the articular tubercle and the maxillary tuberosity, respectively, in conjunction with a forward rotation of the whole mandible. The inferior direction of corpus realignment relative to the basal part of the ramus also increases the notching effect in the antegonial region, an effect augmented by the presence of the resorptive field in the notch itself. Certain specific variations commonly occur in several major regions of the mandible on both the lateral and medial sides...


Cytotoxicity of antisera to a myelogenous leukemia cell line with the Philadelphia chromosome.

Rabbit antisera to myelogenous leukemia (ML) cells were raised; ML cells from line K-562 that has the Philadelphia (Ph) chromosome were used as antigen. Antibodydependent, complement-mediated cytotoxicity was demonstrated by the trypan blue test and Cr release assay for cultured ML cells, whereas no cytotoxicity was demonstrated for cells from B (SB) and T (MOLT 4) lymphoblastoid cell lines. The antisera showed no cross-reactivity for normal human peripheral leukocytes or purified granulocytes. A low level (less than 8%) of cytotoxicity was directed against cell membrane associated fetal bovine serum proteins. Absorption of the immune serum with normal human bone marrow cells of first trimester human whole embryo cells reduced the cytotoxic titer to a similar extent; this suggested the possibility of crossreactivity between ML cells and fetal antigen(s). However, the ML antigen(s) was unrelated to carcinoembryonic antigen (CEA), since absorption with CEA had no effect on the serum cytotoxic titer. The anti-ML sera were cytotoxic for cells taken from 10 patients with chronic myelogenous leukemia and from 3 with acute myelogenous leukemia. In contrast, the leukocytes of 1 of 4 patients with acute lymphocytic leukemia, and 3 of 7 with chronic lymphocytic leukemia shared similar antigenic determinants as demonstrated by cytotoxicity tests. The significance of the cross-reactivity of some lymphatic and ML cells may be the result of the use of rabbit sera that did not distinguish antigens common to both granulocytic and lymphocytic cells, or it may reflect an "immature" or "blastic" antigen present on many leukemia cells.


The spleen in Friend leukemia. I. Prolonged survival of leukemic mice after autoimplantation of spleen tissue.

Friend virus infection of susceptible mice led rapidly to fulminant erythroleukemia and death. Subcutaneous implantation of leukemia spleen bits into splenectomized normal animals led to their early death from Friend leukemia. In contrast, bits of leukemic spleen implanted sc into splenectomized leukemic mice prolonged the survival of these animals. Concomitant with this survival was a reversal of the virus-induced immunosuppression and an increase in the levels of circulating, neutralizing, antivirus activity. This marked difference in response to leukemic spleen implants by leukemic as compared to normal mice reflected previous contact of the former with Friend Virus. Our studies indicated that the Friend virus-infected mouse mounted a resistance to the virus infection, which under certain conditions is capable of reversing the disease process.


The spleen in Friend leukemia. II. Nonleukemic nature of spleen stroma.

Pieces of Friend leukemic spleens implanted sc into mice regenerated into normal-appearing spleens if animals were protected against the leukemia. In unimmunized animals, the implant regenerated normally, but was subsequently infiltrated by leukemia cells. This leukemia cell infiltration required at least 30% stromal regeneration of the implant. The hematopoietic regeneration was primarily a repopulation with cells from the host animal, not with cells indigenous to the donor spleen. The development of the implant, whether normal or leukemic, was retarded by the presence of the host spleen, whether leukemic or normal. These studies strongly suggested that the stromal cells of the spleen are not directly involved in the virus-induced leukemic process but acted as supporting structure for the malignant cells.


Pancreatic carcinoma as a sequel to therapy of lymphoma.

Development of a carcinoma in the pancreas of a young man who had five years previously undergone intensive radiotherapy and subsequent chemotherapy for treatment of a lymphoma suggests that induction of the second neoplasm occurred as the result of the therapy of the first. While definite proof of causality is lacking, a review of recent literature strongly suggests that the association noted in the patient described is more than serendipitous. Increased usage of high-dose radiotherapy, particularly in conjunction with chemotherapy, may be directly related, and it is imperative that such an association be kept in mind when such patients are seen in follow-up.


[Percutaneous chordotomy].

The authors review 134 cases of percutaneous cervical chordotomy in 95 patients; 86 patients suffered from malignant tumors, while the pain was caused by benign growths in only 9 cases. The immediate postoperative findings are compared with the clinical results of the follow-up medical examination. Chronological and numerical data follow on permanent sucesses and recurrence rates. The author's own morbidity and mortality rates are contrasted with those if other authors, and compared with the risk involved in open chordotomy.


[Open spinal operations (anterolateral chordotomy and commissural myelotomy) in modern treatment of pain (author's transl)].

The only significant open pain operations on the spinal cord itself that are routinely in use nowadays are anterolateral chordotomy and commissural myelotomy. Open thoracic chordotomy is still inidcated in cases of malignant growth in the lower body, to be sure of avoiding further neurological involvement in the upper region. Open cervical chordotomy, on the other hand, is now only indicated after unsuccessful percutaneous chordotomy and neurostimulation technics. Commissural myelotomy is still used in specific cases  in specialized clinics. Despite advances in knowledge and more modern methods, the open operations still cannot be anondoned.


[Chronic myelomonocytic leukemia in adults. Apropos of 3 personal cases].

Three cases of chronic myelomonocytic leukaemia are discussed and compared with the most recent data of the literature. The cytomorphological and cytochemical aspects of the disease as well as the therapy are discussed.


External pterygoid myotomy for recurrent mandibular dislocation. Review of the literature and report of a case.

Dislocation of the temporomandibular joint is a condition that requires immediate attention. Several conservative methods are effective in the treatment of the acute episode, but surgical treatment is indicated for chronic dislocation. Many, sometimes conflicting, procedures have been proposed for the surgical treatment of chronic dislocation. Comprehensive review and analysis of the literature reveals that this confusion is generated by a poor understanding of the etiology of chronic dislocation. External pterygoid myotomy is recommended as the surgical treatment of choice since it eliminates the forces responsible for pulling the mandible into the dislocated position. A case is presented to demonstrate the effectiveness of this procedure.


Mural odontogenic epithelial proliferations within the wall of a dentigerous cyst: their significance.

A case of a dentigerous cyst with proliferating odontogenic epithelium in a 5-year-old black boy is presented. A controversy exists in the histologic diagnosis and surgical treatment of this lesion. The accuracy of the pathologic diagnosis is imperative, as it will determine to a great extent the surgical modality of treatment.


Radionuclide bone imaging in the surgical treatment planning of odontogenic keratocysts.

Locally aggressive benign lesions of the jaws, such as odontogenic keratocysts and ameloblastomas, require complete excision in view of the high incidence of recurrence after incomplete surgical removal. Because of the limitations of conventional radiology as the sole technique for determining the extent of these lesions, the use of 99m-technetium-labeled bone-imaging agents is suggested. This method of defining the location of surgical margins is based on the agent's sensitivity as an indicator of subtle changes in bone metabolism. A case of an unusually large recurrent odontogenic keratocyst is presented in which the planning of the surgical procedure was predicated on the results of a bone scan of the jaws in addition to conventional radiology. This diagnostic procedure, especially when used in conjunction with conventional radiology, appears to be of considerable value in defining the extent of a variety of oral-maxillofacial bony lesions.


Sarcoidosis with mandibular involvement. Report of a case.

A case of mandibular involvement in sarcoidosis is presented. The diagnosis was based on positive chest roentgenograms, involvement of superficial and mediastinal lymph nodes of epithelioid tubercles, negative tuberculin test, and negative results of an examination with respect to tubercle bacilli. Mandibular involvement was diagnosed tentatively roentgenographically and verified by histopathologic examination. The mandibular lesion was treated surgically, and the defect healed uneventfully after less than 1 year. Almost complete normalization of the pulmonary lesions had taken place after 2 years.


Congenital neutropenia. Report of a case and a biorationale for dental management.

Congenital neutropenia is characterized by a marked decrease in or lack of circulating PMN's in children with no prior history of drug intake. The neutropenia is persistent and the clinical course is one of early onset of severe, recurrent, and eventually fatal infections. Bone marrow studies show a maturation arrest of neutrophilic precursors. Because of their greatly increased susceptibility to infection, patients with congenital neutropenia present a difficult dental management problem. A case of congenital neutropenia has been presented, as well as a biorationale for dental treatment. On the basis of reports in the literature, the following recommendations for the management of patients with congenital neutropenia are made: 1. The prevention and control of infection and the interception of dental disease before surgical intervention becomes necessary should be the overriding considerations in the management of patients with congenital neutropenia. 2. The carious breakdown of teeth should be prevented by the daily application of a 0.4 per cent stannous fluoride gel in addition to oral hygiene and limitation of sucrose intake. 3. Periodontal therapy should be palliative only, since alveolar bone loss is progressive despite frequent oral hygiene instruction and prophylaxis. The goal of periodontal therapy for patients with congenital neutropenia should therefore be a decrease in gingival inflammation to make the patient's mouth more comfortable and to slow down alveolar bone loss. Periodontal surgery is contraindicated. 4. Bacteremia and subsequent septicemia should be prevented since a minor infection can become life threatening in patients with congenital neutropenia. The patient should rinse for 30 seconds and the gingival sulci should be irrigated with a phenolated antiseptic mouthwash prior to all dental manipulations of the soft tissue. This will significantly reduce the incidence of bacteremia. 5. Surgery should be avoided if at all possible because of the high risk of post-operative infection. All surgery sholld be performed in the hospital, and the patient should be given antibiotics as determined by his physician. Primary closure should be done with fine polyglycolic acid sutures to reduce the chance of infection. If postoperative infection can be prevented, wound healing will progress normally despite the complete absence of PMN's.


Salivary IgA and serum IgG and IgA in recurrent aphthous stomatitis.

Salivary flow rate and sIgA were measured in twenty-one patients suffering from recurrent aphthous stomatitis (RAS). Out of this group ten volunteered for continuous study. In these patients salivary IgA and serum IgA and IgG were measured every 3 days for 3 weeks. All parameters were in the physiologic range of healthy people. No correlation with the clinical condition of the patients was found.


Occurrence of epithelial dysplasia in oral leukoplakia. Analysis and follow-up study of 12 cases.

The histologic material of 500 leukoplakia patients was analyzed in order to define the characteristics of epithelial dysplasia and to correlate the findings with the clinical data. Epithelial dysplasia was found in 120 cases (24 per cent) and was graded as mild, moderate, or severe. The occurrence of dysplasia was highest in the group of erosive leukoplakias. The majority of the severe dysplasias were found on the tongue and lips. Follow-up studies on sixty-eight leukoplakia patients with histologic dysplasia revealed carcinoma in nine cases (13.2 per cent) during the mean observation period of 6.3 years. Leukoplakias of the tongue showed the highest incidence of malignant change.


Atypical benign migratory glossitis. Report of a case with histologic and electron microscopic evaluations.

A case of benign migratory glossitis atypically confined to only one side of the tongue is presented. The diagnosis was confirmed by repeated histopathologic evaluation. Electron microscopic studies revealed a striking intimacy between sensory nerve processes and the basal lamina of the lingual epithelium.


Recurrent "non-Hodgkin's lymphoma presenting with gingival enlargement. Report of a case.

A 66-year-old white woman with recurrent "non-Hodgkin's lymphoma" is discussed. Her initial manifestation of recurrent disease was gingival enlargement. We reviewed the oral manifestations of lymphoma and discussed the course of this patient's disease, with particular attention to the local treatment of the gingival enlargement.


The investigation of microleakage in root canal therapy. An electrochemical technique.

An electrochemical technique employing zero-resistance ammetry is described for evaluating the quantity, rate, and areas permeated in the canal system of a root-filled tooth by 1 per cent potassium chloride. Single-rooted extracted teeth were root-filled by a vertical condensation gutta-percha technique. The teeth were coated from the cementoenamel junction to 3 mm. from the apex with a stopping-off medium, so that the apical foramen and the accessory canals in the area would play a role, but not the lateral canals in the gingival area. The teeth were placed in a potassium chloride solution. When the potassium chloride permeated the apical seal and reached a mild steel rod placed through the occlusal access opening extending 2 mm. into the coronal end aspect of the canal, corrosion of the steel was established and was measured for quantity and rate. This technique suggests the possibility of another pathway for tissue fluid to effect coronal dentinal discoloration. The technique also suggests a quantitative means of measuring apical sealing procedures.


A statistical analysis of anaerobic versus aerobic culturing in endodontic therapy.

Asymptomatic teeth were cultured at four specific stages of endodontic therapy, yielding 148 paired samples. Half of the samples were incubated anaerobically with the use of a new medium, and half were incubated aerobically with the use of a commonly employed endodontic medium. The former proved to be significantly more sensitive in supporting microbial growth from root canals. The results indicate that an aerobic culturing technique alone is not sufficient to reflect the microbiologic status of the canal system.


Tomographic evaluation of 100 patients with temporomandibular joint symptoms.

In this study the temporomandibular joints of 100 patients were examined radiographically. While the results leave many unanswered questions, studies of this type do contribute to an increase in the knowledge of this complex structure. It is anticipated that polycycloidal tomography will provide even greater knowledge of the bony components of the TMJ. More accurate, objective radiographic evidence will unquestionably allow us to approach subjective clinical evidence with greater confidence in relating these factors to diagnosis. Dentistry must recognize that the newer and more sophisticated methods must be utilized to evaluate pathologic changes or disease entities, such as temporomandibular joint dysfunction. A health profession must be provided with maximum information for total diagnosis.


Localization of objects in the anterior areas with a single Panorex radiograph.

Impacted objects in the anterior dental region can be localized in a labial-palatal direction with a single Panorex film. Clark's rule is applied to the two views of the anterior area obtained. The technique is verified by means of a dry skull with lead markers in known positions, and two clinical cases are reported.


Construction of a hybrid col E1 plasmid carrying the gene for bacteriophage lambda repressor.

A biologically active hybrid DNA molecule was constructed from plasmid Col E1 and the Eco R1 fragment of lambda DNA containing the gene for lambda repressor. The presence of this gene in the hybrid molecule was demonstrated genetically. The hybrid plasmid contains two closely located targets for restriction endonuclease Hind 111 in the integrated fragment. Thus, the plasmid may be used as a vector not only for Eco R1 fragments but also for Hind 111 fragments.


Integration of eukaryotic genes for 5S RNA and histone proteins into a phage lambda receptor.

Highly purified HindIII restriction fragments of Xenopus laevis 5S DNA and of Psammechinus miliaris histone DNA have been covalently inserted into a derivative of phage lambda. This phage, genetically constructed by Murray et al. (1), contains only a single target for HindIII in the cI gene. Viable hybrid molecules were detected as clear plaque-forming phage after transfection of E. coli, the vast majority of which were shown by hybridization to be recombinants of the desired type. The lambdaSam7 mutation has been introduced into one hybrid phage containing histone DNA, thereby substantially increasing the yield of recombinant DNA.


Isolation, primary structure, and synthesis of alpha-endorphin and gamma-endorphin, two peptides of hypothalamic-hypophysial origin with morphinomimetic activity.

The isolation and primary structure of two peptides with morphinomimetic activity, obtained from an extract of porcine hypothalamus-neurohypophysis, are described. The amino acid sequence of the two peptides, named alpha-endorphin and gamma-endophin, was determined by mass spectrometry and danxyl-Edman methods to be H-Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr-OH and H-Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr-Leu-OH, respectively. These correspond to the amino acid sequences present between residues 61 and 76 and residues 61 and 77 of the various beta-lipotropins. A third peptide also obtained in pure form in these studies was found to be an unstable salt of alpha-endorphin.


Dependence of interferon induction on nucleic acid conformation.

UV and circular dichroism characteristics of duplex analogs belonging to the (A)n-(U)n and (I)n-(C)n series were determined to assign qualitatively the nature of conformational differences caused by 5-pyrimidine and c7 purine substitutions in such duplexes. Evidence is presented which shows that 5-pyrimidine substitution by bromine or methyl changes the duplex conformation of both series in a similar way, if at all. A c7 substitution in the purine ring affects the duplex conformation of the members in the same series similarly, but the conformational change appears to be different for the two series. To wit, it is proposed that in the duplexes the effect of the change (A)n leads to (c7A)n is an increase of the positive base tilt, whereas the change (I)n leads to (c7I)n causes a decrease where (c7A)n is poly (7-deazaadenylic acid) and (c7I)n is poly(7-deazainosinic acid), respectively. Poly(5-bromocytidylic acid) (br5C)n proved to be useful as  a sensor strand for the intepretation of the spectroscopic data. The circular dichroism findings correlate well with observations made earlier on the interferon inducing ability for such duplexes, namely, duplexes based on the (c7A)n are inactive as interferon inducers, whereas duplexes based on (c7I)n are potent inducers. Furthermore, a 5-pyrimidine substitution does not substantially affect the interferon inducing ability, unless the thermal stability of the analog becomes critical, as in the case of (A)n-(br5U)n. Thus, this study provides the first evidence to link the interferon-inducing ability of a nucleic acid to a defined physical parameter of double helix, and reinforces the concept that interferon induction is dependent on the recognition of a particular spatial and steric organization of a double-stranded RNA.


Role of subunit interfaces in the allosteric mechanism of hemoglobin.

We calculate the surface area buried in subunit interfaces of human deoxyhemoglobin and of horse methemoglobin. A larger surface area is buried in deoxy- than in methemoglobin as a result of tertiary and quaternary structure changes. In both molecules the dimer-dimer interface is closepacked. This implies that hydrophobicity stabilizes the deoxystructure, the free energy spent in keeping the subunits in a low-affinity conformation being compensated by hydrophobic free energy due to the smaller surface area accessible to solvent.


Resonance enhanced coherent anti-Stokes Raman scattering.

Resonance enhancement of coherent anti-Stokes Raman scattering due to the proximity of the laser frequencies to an electronic transition has been demonstrated for dilute solutions of diphenyloctatetrane in benzene. The Raman contribution to the third order susceptibility is shown to be complex near an electronic resonance and the resulting features of the coherent anti-Stokes Raman scattering spectra are discussed in detail. This work represents one step in the demonstration that the high signal to noise ratio, fluorescence rejection, and low average power levels of the coherent anti-Stokes Raman scattering experiment can be used to advantage in Raman studies of dilute solutions and materials of biological interest.


Crystal structure of a complex between lumiflavin and 2,6-diamino-9-ethylpurine: a flavin adenine dinucleotide model exhibiting charge-transfer interactions.

The x-ray structure of the deep red crystalline complex lumiflavin-2,6-diamino-9-ethylpurine has been determined. The flavin and adenine derivatives form hydrogen-bonded base pairs of the Watson-Crick type. The molecules in the crystal also associate via extensively overlapped flavin/adenine and flavin/flavin stacking interactions in which there are several contacts that are closer than van der Waals distances. This, together with the red color of the crystals, is indicative of the formation of a charge-transfer complex.


Nuclear magnetic resonance description of molecular motion and phase separations of cholesterol in lecithin dispersions.

Proton-enhanced 13C nuclear magnetic resonance is used to obtain signals from labeled cholesterols in lecithin dispersions. The [26-(13)C]cholesterol resonance indicates that the aliphatic tail of the molecule undergoes reorientation fast enough to average completely the chemical shift anisotropy. In contrast, [4-(13)C]cholesterol signals are characteristic of limited anisotropic reorientation. The resonances from the 4 position are sensitive to the temperature-concentration phase diagram. A phase boundary is observed at about 20 mole percent cholesterol.


Role of proteolytic enzymes in biological regulation (a review).

Many enzymes, hormones, and other physiologically active proteins are synthesized as inactive precursors (zymogens) that are subsequently converted to the active form by the selective enzymatic cleavage (limited proteolysis) of peptide bonds. The ultimate agency of activating enzymatic function is limited proteolysis, either in a single activation step or in a consecutive series (cascade). The specificity of each activation reaction is determined by the complementarity of the zymogen substrate and the active site of the attacking protease. The sequence of consecutive activation reactions is regulated by the specificity of each enzyme, whereas the degree of amplification of the initial stimulus is determined by the efficiency of each activating step. Zymogen activation produces a prompt and irreversible response to a physiological stimulus, and is capable of initiating new physiological functions. Typical examples are the precesses of blood coagulation, fibrinolysis, complement activation, hormone production, metamorphosis, fertilazation, supra-molecular assembly, and digestion. The zymogens of the pancreatic serine proteases, in particular, have served as models for detailed studies of the nature of the molecular changes that are involved in the dramatic increase in enzymatic activity that ensues upon limited proteolysis of the zymogen.


Synthesis and activities of neurotensin, and its acid and amide analogs: possible natural occurrence of [Gln4]-neurotensin.

It was considered, a priori, that the isolation of the tridecapeptide, neurotensin, might have inadvertently sllowed the hydrolysis of either the [Gln4]- or the [Leu13-NH2]-moieties. Neurotensin and its three acid and amide analogs, i.e., [Gln4]-neurotensin, neurotensin-NH2, and [Gln4]-neurotensin-NH2 were synthesized. Neurotensin and [Gln4]-neurotensin were indistinguishable by the hypotensive assay, hyperglycemic assay, contraction of the ileum, and radioimmunoassay. Neurotensin-NH2 and [Gln4]-neurotensin-NH2 showed less than 1% of these neurotensin activities. Present information does not elucidate whether the glutamic acid residue in position 4 of neurotensin in situ is present as Glu4 or as Gln4. At high levels, neurotensin released the luteinizing hormone, follicle stimulating hormone, and thyrotropin; [Gln4]-neurotensin-NH2 released thyrotropin, and [Gln4]-neurotensin released luteinizing hormone and follicle stimulating hormone, but these activities do not appear biologically significant.


Viroids are single-stranded covalently closed circular RNA molecules existing as highly base-paired rod-like structures.

Viroids are uncoated infectious RNA molecules pathogenic to certain higher plants. Four different highly purified viroids were studied. By ultracentrifugation, thermal denaturation, electron microscopy, and end group analysis the following features were established: (i) the molecular weight of cucumber pale fruit viroid from tomato is 110,000, of citrus exocortis viroid from Gynura 119,000, of citrus exocortis viroid from tomato 119,000 and of potato spindle tuber viroid from tomato 127,000. (ii) Viroids are single-stranded molecules. (iii) Virods exhibit high thermal stability, cooperativity, and self-complementarity resulting in a rod-like native structure. (iv) Viroids are covalently closed circular RNA molecules.


Investigation of phase transitions of lipids and lipid mixtures by sensitivity differential scanning calorimetry.

High sensitivity differential scanning calorimetry is applied to the study of the thermotropic behavior of mixtures of synthetic phospholipids in multilamellar aqueous suspensions. The systems dimyristoylphosphatidylcholine dipalmitoylphosphatidylcholine, and  dimyristoylphosphatidylethanolamine-distearoylphosphatidylcholine, although definitely nonideal, exhibit essentially complete miscibility in both gel and liquid crystalline states, while the system dilauroylphosphatidylcholine-distearoylphosphatidylcholine is monotectic with lateral phase separation in the gel state. Comparison of the observed transition curves with theoretical curves calculated from the calorimetrically determined phase diagrams supports a literal interpretation of the phase diagrams.


(+/-)-trans-7,8-dihydroxy-7,8-dihydrobenzo (a)pyrene: a potent skin carcinogen when applied topically to mice.

(+/-)-trans-7,8-Dihydroxy-7,8-dihydrobenzo[a]-pyrene, a known metabolite of benzo [a]pyrene, has been tested for carcinogenic activity on mouse skin by topical application of 0.15 or 0.30 mumol every 2 weeks for 60 weeks. At the low dose (0.15 mumol), the compound was equipotent to the parent hydrocarbon, benzo[a]pyrene, and considerably more potent than its metabolic precursor, benzo[a]pyrene 7,8-oxide, in eliciting tumors, as determined by both the onset of tumors and the total number of animals developing carcinomas. Application of 7,8-epoxy-,8,9,10-tetrahydrobenzo[a]pyrene (0.30 mumol every 2 weeks), a compound related to the carcinogenic benzo[a]pyrene 7,8-oxide but with the double bond removed from the 9,10-position of the molecule, did not elicit any tumors. The above results indicate that the (+/-)-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene is a more proximate carcinogen than benzo[a]pyrene 7,8-oxide and that the carcinogenicity of benzo[a]pyrene 7,8-oxide and (+/-)trans-7,8-digydrobenzo[a]pyrene may be due to metabolic conversion of these compounds to the highly reactive and mutagenic stereoisomers of 7,8-digydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene.


Mechanism of action of carboxypeptidase A in ester hydrolysis.

The reaction of carboxypeptidase A (peptidyl-L-amino-acid hydrolase; EC 3.4.12.2) with the specific ester substrate O-(trans-p-chlorocinnamoyl)-L-beta-phenyllactate has been investigated in the temperature range 25 degrees to -40 degrees with use of organic-aqueous cosolvent mixtures. In the subzero temperature range the hydrolysis reaction is characterized by a biphasic decrease in absorbance specific for the substrate. The kinetic data can be unambigously analyzed as two consecutive first-order reactions with formation of a covalent acyl-enzyme intermediate. Deacylation of the covalent intermediate is shown to be rate-limiting in the subzero temperature range, and near -60 degrees it is sufficiently stable for spectral characterization. Consideration of the structure of the active site and of the catalytically functional residues of the enzyme leads to the conclusion that the intermediate is a mixed anhydride in which the gamma-carboxylate of glutamate-270 is acylated by the substrate. The temperature dependence of the rate constants of the acylation and deacylation steps explains why the intermediate of this enzyme-catalyzed reaction is observed only at low temperatures.


Reconstitution of intramembrane particles in recombinants of erythrocyte protein band 3 and lipid: effects of spectrin-actin association.

The integral membrane protein Band 3 of the human erythrocyte, either purified or in a crude Triton X-100 extract of ghosts, was combined with egg lecithin in a cholate solution. During dialysis to remove cholate, lipid bilayer vesicles formed in which Band 3 existed as a dimer and in which intramembrane particles indistinguishable from those in the native membrane were exposed by freeze-fracturing. The recombinant vesicles were stable in both high and low salt concentrations, sedimented at a density that increased in prportion to their protein content, and bound spectrin-actin extracted from erythrocyte ghosts. When spectrin-actin was associated with the vesicles, the behavior of the recombinant intramembrane particles simulated that of the erythrocyte ghost intramembrane particles: they were dispersed at pH 7.6 and aggregrated at pH 5-5.5. Thus, some of the characteristics of the native membrane have been reconstituted in the recombinant.


Photoreceptor pigment that induces differentiation in the slime mold Physarum polycephalum.

An extract of small molecules (molecular weight less than 500) of the slime mold Physarum polycephalum undergoes a shift in ultraviolet-visible absorption spectrum upon illumination. This illumination also confers on the extract the ability to induce sporulation when injected into a starved, unilluminated slime mold. The spectral shift and appearance of the sporulation-inducing activity both occur regardless of whether the illumination is carried out on an intact slime mold or on the plasmodium-free extract itself. Thin-layer chromatography resolves the slime mold extract into four major visible fractions. One of these has high sporulation-inducing activity after illumination in vitro.


A plasmid cloning vehicle allowing regulated expression of eukaryotic DNA in bacteria.

We have constructed a plasmid cloning vehicle in which transcription of inserted heterologous DNA fragments can be regulated by a defined bacterial operator and promoter. The lambda plac 5 EcoRIDNA fragment containing the operator, promoter, and beta-galactosidase gene of the lactose operon was linked to the ColE1 derivative plasmid pSF2124, creating a plasmid designated pBGP100, pBGP100 contains one EcoRI site at the lac DNA/pSF2124 DNA junction and another at the lambda DAN/pSF2124 DNA junction. We deleted the latter EcoRI site to generate a plasmid (pBGP120) retaining a single EcoRI site at the lac DNA/nSF2124 DNA junction. To determine whether DNA introduced at the EcoRI site of pBGP120 was expressed under lactose control, we inserted the EcoRI fragment containing 28S ribosomal DNA of Xenopus laevis, creating the hybrid plasmid pBGP123. RNA-DNA hybridization of pulse-labeled RNA from cells containing pBGP123 showed that induction of the lac operon increases the percentage of labeled RNA complementary to Xenopus 28S DNA about 9-fold. This vehicle may be of use for production of eukaryotic gene products in bacteria.


5-bromodeoxyuridine-DNA strand symmetry and the repair of photolytic breaks in Chinese hamster cell chromosomes.

Experiments described in this report quantiate the black light sensitivities of Chinese hamster lung (CHL) cells containing BrdUrd-DNA of defined composition. Cesium chloride equilibrium gradient centrifugation provides estimates both of the percent thymidine replacement by BrdUrd and of the symmetry (unifilar versus bifilar) of BrdUrd incorporation into the chromosomal DNA duplexes. Radiation damage to BrdUrd-substituted CHL cell DNA and its repair in situ also have been assessed by alkaline sucrose gradient sedimentation. We observe that animal cell sensitivities to visible light (300-400 nm wavelength) depend markedly upon the symmetries of BrdUrd-substitution within the cells Dna. Cells that contain only unifilar BrdUrd-DNA are resistant to black light, whereas cells that contain bifilar BrdUrd-DNA are extremely photosensitive. The former cell populations repair single-stranded  nicks (breaks in phosphodiester bonds) in their DNA within 24 hr of irradiation; the latter cell populations, however, are not able to repair light-induced, double-stranded breaks in their DNA.


DNA methylation in adenovirus, adenovirus-transformed cells, and host cells.

DNAs of adenovirus type 2 and type 12 contain low amounts of methylated bases (0.01 and 0.02% N6-methyl-adenine per adenine, if any, and 0.04 and 0.06% 5-methylcytosine per cytosine for type 2 and type 12, respectively), whereas the DNA of the mammalian host cells contains much more 5-methylcytosine (3.57% for human KB cells). The DNA of hamster cells transformed by adenovirus type 12 contains 3.11 and 3.14% 5-methycytosine (HA12/7 and T627 cells, respectively), whereas the DNA from untransformed hamster cells (BHK21 cells) contains 2.22% 5-methylcytosine. In the DNA of human and hamster cells, little, if any, N6-methyladenine was detected. Methylation of DNA was determined by a sensitive method based on two consecutive steps of two-dimensional thin-layer chromatography of the radioactively labeled DNA bases. By this procedure the detection limits of 5-methylcytosine and N6-methyladenine could be lowered to 0.01% per main base.


Activation of chromatin by acetylation of histone side chains.

The ability of calf thymus chromatin to support DNA-dependent RNA synthesis is markedly increased by modification of the histones with acetic anhydride. The extent of chemical acetylation of histones H2a, H2b, H3, and H4 required for the increase of template activity of the chromatin is within that which can be achieved enzymatically in the cell. The evidence suggests that the acetylation of histone side chains stimulates the rate of chain elongation during transcription of chromatin.


Selective digestion of transcriptionally active ovalbumin genes from oviduct nuclei.

Analysis of the DNA of isolated nucleosomes suggests that virtually all genomic DNA sequences are organized in this basic chromatin subunit. In this report, we demonstrate that although histones reside on the transcriptionally active ovalbumin genes in the oviduct, the organization of proteins about this gene renders it highly sensitive to deoxyribonuclease I (deoxyribonucleate 5'-oligonucleotidohydrolase, EC 3.1.4.5). Treatment of oviduct nuclei from the laying hen with pancreatic deoxyribonuclease I results in the preferential digestion of over 70% of the ovalbumin sequences when only 10% of the total nuclear DNA has been solubilized. Treatment of liver nuclei does not reveal selective sensitivity of these genes to DNase I. Furthermore, regions of DNA not actively transcribed, such as the endogenous leukosis virus genes in the oviduct, are not selectively degraded by this enzyme. Similar digestions with micrococcal nuclease, however, reveal no specific digestion of transcriptionally active chromatin. These data confirm the observations of H. Weintraub and M. Groudine [(1976) Science 193, 848-856] and suggest we are dealing with an aspect of structure that may be necessary to permit transcription of the chromatin complex.


A method for the modulation of membrane fluidity: homogeneous catalytic hydrogenation of phospholipids and phospholipids and phospholipid-water model biomembranes.

The fatty acids associated with phospholipids of cell membranes, and particularly their degree of unsaturation, contribute to the fluidity of their structure and hance determine many of their biological properties. We describe a technique for modulating membrane fluidity which consists of hydrogenating the unsaturated double bonds of membrane phospholipids. This has been accomplished using a homogeneous catalyst. The process has been applied to phospholipids in organic solvents, to phospholipids dispersed as multibilayers in aqueous systems, and also to sonicated preparations of phospholipids arranged as single bilayer vesicles. Preliminary experiments have also been performed with biological membranes. These results indicate that the process of homogeneous catalysis for the modulation of lipid fluidity of biological cell membranes may have considerable future biological and biochemical application.


Changes in levels of cellular retinol- and retinoic-acid-binding proteins of liver and lung during perinatal development of rat.

Cellular retinol-binding protein and cellular retinoic-acid-binding protein, canditates for mediating the action of vitamin A, were found to be present in tissues of the fetal rat. Cellular retinol-binding proteins were still present in most tissues of the adult, but the retinoic-acid-binding protein was not detected in some, including lung, liver, intestine, and kidney. During perinatal development of lung the level of cellular retinol-binding protein remained relatively constant while the level of the cellular retinoic-acid-binding protein peaked at 10 days postnatally, then declined. It was not detectable in lung tissue from 21-day-old rats. In liver, however, the retinoic-acid-binding protein was not detectable later than 5 days postnatally, while the level of the cellular retinol-binding proteinrose sharply near birth, declining only after 21 days to the lower adult levels. The variations observed in the levels of the two binding proteins suggest different and changing requirements for retinol and retinoic acid in organ development and maturation.


Presence of diadenosine 5',5''' -P1, P4-tetraphosphate (Ap4A) in mamalian cells in levels varying widely with proliferative activity of the tissue: a possible positive "pleiotypic activator".

An accurate assay of diadenosine 5',5'''- P1,P4-tetraphosphate [A(5') pppp(5')A], which was shown to be formed in vitro in the backreaction of the amino acid activation step, has been developed in various cell lines in culture and in normal mouse liver or hepatoma in vivo. Use of radioactive labeling of acid-soluble nucleotides to high specific activity  followed by chromatographic separation techniques yielded levels of Ap4A varying from 5 to 0.05 muM (from 30 pmol/mg of protein to 0.15 pmol), depending on the doubling time of the cell line or the proliferative state of the cells. The levels of Ap4A incells is inversely related to their doubling time, varying from 0.1  X 10(-4) of the cellular ATP levels in slowly growing cells to 20 X 10(-4) of the ATP levels of cells with rapid doubling times. The steady-state levels of ATP of different cell lines, although showing some fluctuations, are not related to the doubling time of the cells. Arrest of cellular proliferation by serum deprivation or amino acid starvation, which does not alter the cellular ATP levels more than 2-fold, does nevertheless cause a decrease of 30 to 50-fold in the Ap4A levels. Inhibition of protein synthesis by pactamycin or puromycin, or inhibition of DNA synthesis by hydroxyurea, leads to a more dramatic decrease of 50 to 100-fold in intracellular Ap4A levels. The metabolic lability of Ap4A is also demonstrated by its rapid depletion after decreases in the ATP/ADP ratio. The possibility of Ap4A being a metabolic "signal nucleotide" that is formed at the onset of protein synthesis and is active in positive growth regulation (positive pleiotypic activation) is discussed.


Colicin E2 is DNA endonuclease.

Colicin E2 purified by conventional methods contains a tightly bound low-molecular-weight protein, as has been found with purified colicin E3 [Jakes,N.&Zinder,N.D.(1974) Proc. Natl. Acad. Sci. USA 71, 3380-3384]. Such E2 preparations do not cause DNA cleavage in vitro. After separation from the low-molecular-weight protein, colicin E2 retained the original in vivo killing activity, and in addition showed a high activity in vitro in cleaving various DNA molecules, such as a ColE1 hybrid plasmid and DNAs from Escherichia coli, lambda phage, chiX174 phage, and simian virus 40. The low-molecular-weight protein ("E2-immunity protein") specifically prevented this in vitro DNA cleavage reaction, i.e., had an "immunity function." The results demonstrate that colicin E2 itself is a DNA endonuclease and explain the in vivo effects caused by E2 in sensitive cells as well as the mechanism of immunity in E2-colicinogenic cells.


Dynamic properties of isolated acetylcholine receptor protein: kinetics of the binding of acetylcholine and Ca ions.

Kinetic and thermodynamic constants for elementary steps associated with the interaction of acetylcholine (AcCh) and Ca with isolated AcCh receptor from Torpedo californica have been determined by chemical relaxation spectrometry. Murexide as used as a Ca indicator to monitor changes in Ca bound to the AcCh receptor. In the presence of AcCh this technique permits an indirect monitoring of AcCh binding, because the AcCh and the Ca binding reactions are competitively coupled. A temperature-jump perturbation in the Camurexide-AcCh receptor system induces a spectrum of relaxation processes characterized by at least three relaxation times: tau1 = 5 (+/-1) msec; tau2 = 35 (+/-5) msec; and tau3 = 300 (+/-30) msec. In the presence of AcCh, the Ca relaxation spectrum is altered in a characteristic way. A formalism is developed to describe the normal mode relaxation times of the coupled reaction system in terms of total concentrations of both AcCh and receptor binding sites. The analysis also allows one to determine the stoichiometry of the reactions involved or to estimate a molecular weight of the AcCh receptor. The kinetic data suggest that the reaction of AcCh with receptor proceeds in at least two steps. The rate constant of the association of AcCh with receptor was found to be 2.4(+/-0.5) X 10(7) M-1 sec-1 at 23.5 degrees, 0.1 M NaCl, 50 mM Tris-HCl, pH 8.5. Reaction schemes consistent with the present kinetic data are discussed in terms of physiocochemical model that accounts for the rapid transient conductivity changes in excitable membranes during nerve and muscle excitation.


Nuclear magnetic resonance studies of the interaction of general anesthetics with 1,2-dihexadecyl-sn-glycero-3-phosphorylcholine bilayer.

Sonicated 1,2-dihexadecyl-sn-glycero-3-phosphorylcholine forms liposomes. Studies by Fourier transform proton magnetic resonance of the interaction of these bilayers with some general anesthetics, i.e., chloroform, halothane, methoxyflurane, and enflurane, show that the addition of a  general anesthetic to the liposomes and raising the temperature have a similar effect in cuasing the fluidization of the bilayer. General anesthetics act on the hydrophilic site (choline group) in clinical concentrations and then diffuse into the hydrophobic region with the addition of larger amount of anesthetics. There is evidence that the lecithin choline groups are involved in the interaction with protein and that the general anesthetics change the conformation of some polypeptides and proteins. We conclude that the general anesthetics, by increasing the motion of positively charged choline groups and negatively charged groups in protein, weaken the Coulomb-type interaction and cause the liprotein conformational changes.


Analogue solution for electrical capacity of membrane-covered cubes in cubic array at high concentration.

Earlier measurements have shown that the equations derived for the resistance of suspension of spheres apply up to a volume concentration of 100% for close-packing forms. They have also shown, by a resistance-capacitance analogue, that they apply for the capacity of a close-packing of membrane-covered square cylinders in square array, approximating muscle and nerve. The present work is an extension of the two-dimensional to a three-dimensional array of membrane-covered cubes in a cubic array. It is found by measurements of a three-dimensional electrolytic analogue that the capacitance is indeed expressed by an extension of the analytic solution at low concentrations up to 100% volume concentration of the membrane-covered form, such as epithelial tissues. There is thus at least one example each of two-and three-dimensional forms which conform to the low concentration analysis up to 100% volume and so give a basis for the extensions to other and more complicated forms to complete a survey to work begun by Fricke in 1923.


Quantized generation time in mammalian cells as an expression of the cellular clock.

The distribution of possible generation times in mammalian cells does not appear to be continous within the limits of range for each cell type; rather, generation time is quantized in multiples of 3-4 hr. Synchronous cultures of Chinese hamster V79 cells were prepared using manual and automated methods to select and stage mitotic cells. Using synchronous cultures and time-lapse video tape microscopy, it was possible to show that generation times within a population of mitotically selected cells normally disperse in a quantized fashion, with intervals of 3-4 hr occurring between bursts in division. In addition, at temperatures above 37 degrees, V79 cells have a 7.5-8.5 hr modal cell cycle, while at temperatures from 36.5 degrees to 33.5 degrees the modal cell cycle is 11-12 hr long. A survey of the synchrony literature reveals that the tendency to preferred generation times holds between cell lines. The distribution of modal generation times from a variety of different cell types forms a series with a similar interval but with a greater range of values than that observed here for V79 cells. To satisfy the published data and the work presented here, I propose a subcycle, Gq, which has a traverse time equal to the period of the clock. The period appears to be fixed at close to the same value in all mammalian somatic cells. The timekeeping mechanism appears to be temperature compensated, since the time required to traverse Gq is constant at temperatures between 34 degrees and 39 degrees. It is suggested that cell cycle time increases at lower temperatures, lower serum concentration, and high cell densitite because the number of rounds of traverse through Gq increases.


Collagen fibrillogenesis: intermediate aggregates and suprafibrillar order.

Polymerization of collagen in vitro has been studied with the electron microscope at early time points of fibril assembly. We have found morphologically distinct stages of aggregation, which we suggest represent successive steps in fibril formation. Linear growth of the fibril appears to occur by the tandem addition of aggregates to each other and subsequently to the ends of a subfibril; lateral growth occurs by the entwining, like a rope, of these subfibrils. Fibrillogenesis is also accompanied by extensive development of suprafibrillar order in which various patterns of parallel, spiral, and orthogonal sets of fibrils were frequently observed.


Actin-like filaments amd membrane rearrangement in oxyntic cells.

The secretory pole of vertebrate oxyntic cells possesses two distinct membrane systems: the apical plasma membrane which presents numerous infoldings, microvilli and processes, and a complex tubulovesicular system located in close proximity to the plasma membrane. These two membrane systems are generally believed to be interconvertible in relation to the functional state of the cell. To determine the role that filaments may play in the interconversion process, the secretory pole of rat and toad oxyntic cells was examined by electron microscopy under conditions designed to demonstrate filamentous structures, i.e., slight cellular swelling and incubation with heavy meromyosin. Filaments 50-80 A in diameter are present in close association with the plasma membrane to which they are connected by regularly spaced bridges. Heavy meroxyosin-treated material reveals "decorated" filaments in topographically corresponding locations. No filaments are seen in association with membranes of the tubulovesicular system. These findings suggest that association with actin-like filaments is a step in the translocation of membranes from the tubulovesicular system to the plasma membrane.


Simultaneous synthesis of types I and III collagen by fibroblasts in culture.

Specific antibodies against types I and III collagens and procollagens were used to localize these proteins in cultured human cells. These studies indicate that the same cell makes both proteins. No type III procollagen synthesis was observed in cells from two patients with two patients with the Ehlers-Danlos type IV syndrome.


Tissue interaction in androgen response of embryonic mammary rudiment of mouse: identification of target tissue for testosterone.

In the androgen response of the embryonic mammary rudiment of the mouse, both gland epithelium and surrounding mesenchyme are visibly involved. The question whether this is due to a direct action of testosterone on both tissues was investigated in experimental combination of mammary epithelium and mammary mesenchyme, derived either from normal or from androgen-insensitive (XTfm/Y) embryos. A typical androgen response occurred in combinations of androgen-insensitive epithelium with normal mesenchyme, whereas all combinations of normal epithelium with androgen-insensitive mesenchyme failed to respond. It is therefore concluded that only the mesenchyme of the mammary rudiment is the target tissue for testosterone, and that all changes in the gland epithelium, including its necrosis, are secondarily caused by testosterone-activated mesenchymal cells.


Subcellualr distribution of protein carboxymethylase and its endogenous substrates in the adrenal medulla: possible role in excitation-secretion coupling.

Protein carboxymethylase (S-adenosyl-L-methionine:protein O-methyltransferase, EC 2.1.1.24) transfers a methyl group from S-adenoxyl-L-methionine to carboxyl side chains of proteins to form labile protein-methyl esters which, thus, neutralize negative charges. This enzyme was examined for its possible participation in excitation-secretion coupling in the adrenal medulla. Protein carboxymethylase has a specific activity several times higher in the adrenal medulla than in the adrenal cortex; also, the medulla has a higher concentration of methyl-acceptor proteins. In the adrenal medulla, 97% of the enzyme was localized in the cytosol. Of the various subcellular fractions of the medulla, the catecholamine-containing chromaffin vesicles had the highest concentrations of substrat(s) for protein carboxymethylase. Carboxymethylation of proteins in intact chromaffin vesicles results in stripping of methylated protein(s) from the membranes. Thus, protein carboxymethylase appears to be involved in the neutralization of charges on the surface of chromaffin vesicles and in the release of surface proteins; both phenomena are likely to be required for exocytosis.


Tubulin requires tau for growth onto microtubule initiating sites.

Tubulin purified by phosphocellulose chromatography and free of accessory proteins will not form microtubules in the absence or presence of microtubule initiating sites (flagellar microtubules). The capacity for growth onto pre-existing "seeds" can be restored by the addition of small quantities of partially purified tau protein. Larger quantities restore the capacity for spontaneous assembly. These results suggest that tubulin requires tau for both initiation and growth of microtubules and that tau is incorporated into the microtubule throughout its length.


Clustering and endocytosis of membrane receptors can be induced in mature erythrocytes of neonatal but not adult humans.

Concanavalin A (Con A) is taken up by endocytosis in mature erythrocytes of newborn humans but not in adult red cells. Thin sections of neonatal cells incubated with ferritin-conjugated Con A at 37 degrees show ferritin clusters on invaginations at the surface and in intracellular vesicles, but such invaginations and vesicles are absent with adult cells. The endocytosis induced by ferritin-conjugated Con A is inhibited at 0 degrees, and by methyl-alpha-D-mannopyranoside at 37 degrees. Succinylation of Con A, which is known to convert it from the tetrameric to dimeric form, renders Con A inactive in cell agglutination and endocytotic vesicle formation, presumably by reducing the number of oligosaccharide chains simultaneously bound by a single Con A molecule. Ferritin-conjugated succinyl Con A binds to neonatal erythrocytes but does not induce endocytosis; if, however, antibodies to ferritin are now added, endocytosis occurs. These results are consistent with a greater lateral mobility of at least a fraction of Con A recptors in the membrane of the intact neonatal erythrocyte compared to the adult. The results also support the hypothesis that the clustering of receptors is obligatory for endocytosis to occur. No discernible difference was found in the sodium dodecyl sulfate/polyacrylamide gel patterns of the membrane proteins of the neonatal and adult cells.


Embryonal carcinoma antigen and the T/t locus of the mouse.

The presence of the F9 antigen and of four other antigens related to the T/t locus of the mouse was investigated by immunofluorescence on preimplantation embryos. In morulae heterozygous for any of these t haplotypes, both the appropriate t antigen and the F9 antigen are expressed. The F9 antigen segregates among the progeny of crosses producing embryos homozygous for some (tw32 and tw5) but not for other haplotypes. It is concluded that (i) whatever the time of action of a t haplotype, its corresponding antigen is expressed during cleavage and (ii) the F9 antigen is specified by a gene(s) in the region of the T/t locus.


Active cell edge and movements of concanavalin A receptors of the surface of epithelial and fibroblastic cells.

Movements of the receptors of concanavalin A on various parts of the surfaces of substrate-attached cells were compared. Cultured mouse embryo cells of several types were used: epithelial kidney cells and normal and transformed fibroblasts. Initial distribution of receptors was random on the cells of all types. Binding of concanavalin A induced patching of its receptors on all the cell parts. In contrast, directional centripetal movement of receptors was observed only on the surface of certain cell parts, namely, only the surface of peripheral lamellar cytoplasm was cleared of the receptors. Clearing was always initiated in the zone of lamellar cytoplasm located near active cell edges. In epithelial sheets, clearing was not observed on the surface of central cells that had no lamellar cytoplasm. Concanavalin A receptors on the cleared areas of cell surface were gradually restored after the end of incubation. It is suggested that anchoring of the patches of membrane receptors by cortical microfilaments is possible only on the surface of pseudopods and of lamellar cytoplasm but not on the surface of other cell parts. Besides receptor movements, this hypothesis may be explain differences in the adhesive properties of various parts of the cell surface.


Differential labeling of the cell surface of single ciliary ganglion neurons in vitro.

Cationic ferritin binds in a time and concentration dependent manner to all surfaces of ciliary ganglion neurons in culture except "mounds" and "veils". In chase experiments, bound ferritin clears from the cells surfaces and forms larger and larger patches, even at low temperatures. Binding of cationic ferritin is inhibited by poly-L-lysine, potentiated by poly-L-glutamate, and not affected by neruaminidase (acylneuraminyl hydrolase, EC 3.2.1.18), hyaluronidase (hyaluronoglucosidase, hyaluronate 4-glycanhydrolase, EC 3.2.1.35), or chondroitin ABC lyase (EC 4.2.2.4).


Survival of fetal rat pancreases frozen to -78 and -196 degrees.

Transplantation of pancreases may have clinical utility in the treatment of diabetes, for it has been shown that chemically induced diabetes in rats can be reversed by the transplantation of greater than or equal to four syngeneic fetal pancreases. Allogeneic transplants produce serious immunological problems, but the problems could be ameliorated if tissue-typed organs could be stored in the frozen state. Unfortunately, nearly all attempts to freeze organs have failed. Nevertheless, recent developments in the physical-chemical analysis of freezing injury and its successful application to the freezing of mammalian embryos encouraged us to attempt the freezing of 16 1/2- to 17 1/2-day intact fetal pancreases. The analysis indicated that to achieve success pancreases would have to be cooled less than 1 degree/min and diluted extremely slowly after thawing. Experiments with embryos and red cells indicated that high survivals might require high concentrations of protective solutes and slow warming. These predictions were accurate. After freezing to -78 or -196 degrees and thawing under optimal conditions, the fetal pancreases synthesized 80-100% as much protein as unfrozen controls and they yielded viable allografts. Optimal conditions included suspension in 2 M dimethylsulfoxide, freezing at 0.3 degrees/min, and slow dilution to preclude osmotic shock.


Growth of human diploid fibroblasts in the absence of glucose utilization.

Normal human diploid fibroblasts were able to undergo one to two cell divisions without glucose utilization in Eagle's minimum essential medium plus 10% dialyzed fetal calf serum if the medium was supplemented with hypoxanthine, thymidine, and uridine (supplemented medium termed HTU-MEM). Under these conditions, the added purine and pyrimidines were required for nucleic acid synthesis, as shown by the inability of Lesch-Nyhan fibroblasts to grow in HTU-MEM. Normal human diploid fibroblasts continued to produce lactate in HTU-MEM, but at a greatly reduced rate. Since cells grew in HTU-MEM without glucose utilization, the probable energy and carbon source was glutamine, which is present in relatively high concentration. Furthermore, the rate of glutamine utilization per cell division was 2-fold greater in HTU-MEM than in medium with 5.5 mM glucose. These results suggest that glutamine can be a major energy source for cells grown in vitro.


Direct method for detection and characterization of cell surface receptors for insulin by means of 125I-labeled autoantibodies against the insulin receptor.

Autoantibodies directed against the cell surface receptors for insulin are found in some patients with extreme insulin resistance. These antibodies specifically inhibit the binding of insulin to its receptor. A purified IgG fraction from one patient's plasma was labeled with 125I. The 125I-labeled antireceptor antibody, which initially represented about 0.3% of the total 125I-IgG, was enriched by selective adsorption and subsequent elution from cells rich in insulin receptors. The 125I-antireceptor antibody bound to cells and the binding was inhibited by whole plasma and purified IgG from this patient, as well as whole plasma from another patient with autoantibodies to the insulin receptor. Insulins that differed 300-fold in biological potency and affinity inhibited binding of 125I-antireceptor antibody in direct proportion to their ability to bind to the insulin receptor. The binding of 125I-antireceptor antibody was closely correlated with the binding of 125I-insulin over a wide range of receptor concentrations on different cell types. Experimentally induced reduction of the insulin receptor concentration was associated with parallel decreases in the binding of 125I-antireceptor antibody and 125I-insulin. The preparation of 125I-antireceptor antibody with a high specific activity by cytoadsorption and elution has provided a sensitive method for the detection of receptors and autoantibodies to cell surface components.


Clonal growth of bovine vascular endothelial cells: fibroblast growth factor as a survival agent.

Bovine vascular endothelial cells do not grow when cultured at low density unless fibroblast growth factor is included in the culture medium. When endothelial cells obtained from the intimal surface of fetal and adult aortas were seeded at low density (8 cells per cm2), they formed small colonies of large, irregular, vacuolated cells. At very low density (0.3 cells per cm2) they did not survive. The addition of fibroblast growth factor to endothelial cells maintained at such low densities resulted in the formation of vigorously growing colonies of small, uniform cells. Electron microscopy showed that the cultured endothelial cells had the fine structure characteristics of endothelial cells. Immunofluorescence microscopy revealed antihemophilic factor (Factor VIII) antigen in the cells. Our results demonstrated that fibroblast growth factor permits the survival of endothelial cells plated at extremely low cell density. With the use of fibroblast growth factor, endothelial cell clones are easily produced.


Superstructure of linear duplex DNA.

The superstructure of a covalently closed circular DNA (of bacteriophage PM 2) was compared by electron microscopy with that of a linear duplex DNA (of bacteriophage T7) when ionic strength and benzyldimethylalkylammonium chloride concentration were varied. In parallel studies the sedimentation behavior of these DNAs was studied by analytical ultracentrifugation, but for technical reasons these had to be without benzyldimethylalkylammonium chloride. By combining the information from the two methods one has to conclude that with increasing ionic strength the linear duplex T7 DNA spontaneously forms a structure similar to that of the superhelical structure of closed circular PM 2 DNA. The superstructure is destroyed under premelting conditions and in the presence of an excess of ethidium bromide.


Repair tracts in mismatched DNA heteroduplexes.

Heteroduplexes with mismatches at four sites were constructed from separated strands of lambda DNA and used to transfect Escherichia coli under recombinationless conditions. The output phages from 967 single cells in one experiment and 1016 in another were analyzed to determine the pattern of mismatch repair. A wide range of repair frequencies was found among the mismatches studied. Repair involving two or more close sites in the same heteroduplex occurs much more often on thesamestrandthanonopposite strands. Analysis of the pattern of repair suggeststhat repair tracts initiate at mismatches, propagate preferentially in the 5'leads to 3' direction, and extend an average distance of ca 3000 nucleotides.


Allelic heterogeneity within allozymes separated by electrophoresis in Drosophila pseudoobscura.

Electrophoretic separation of esterase-5 allozymes of Drosophila pseudoobscura in gels of different acrylamide concentrations and in different buffer systems has revealed the existence of six different alleles within the most frequent class, esterase-5(1.00), and three alleles in the other most frequent class, esterase-5(1.07). Two of the alleles affect subunit binding. Esterase-5 allozyme classes based on electrophoresis in 5% acrylamide gels are therefore highly heterogeneous.


Heat mutagenesis in bacteriophage T4: the transversion pathway.

Heat induces transversions (as well as transitions) at G-C base pairs in bacteriophage T4. The target base for transversions is guanine,which is converted to a product which is sometimes replicated and transcribed as a pyrimidine.A model for this process is proposed in which the deoxyguanosine glycosidic bond migrates from N9 to N2: the resulting deoxyneoguanosine may pair with normal guanine to produce G-C leads to C-G transversions.


Infinite allele model with varying mutation rate.

Available data suggest that the variation in mutation rate among protein loci follows the gamma distribution. Thus, taking into account this variation, formulae are developed for the distribution of allele frequencies, mean and variance of heterozygosity, expected number of alleles, proportion of polymorphic loci, and genetic distance. These formulae should be more appropriate for the analysis of gene frequency data for protein loci than equivalent formulae with constant mutation rate.


Construction of plasmids carrying the cI gene of bacteriophage lambda.

By techniques of recombination in vitro, we have constructed a plasmid bearing the repressor gene (cI) of bacteriophage lambda fused to the promoter of the lac operon. Strains carrying this plasmid overproduce lambda repressor. This functional cI gene was reconstituted by joining DNA fragments bearing different parts of that gene. Flush end fusion techniques, involving no sequence overlap, were necessary for the construction; in certain cases, the abutting of the DNA molecules bearing ends generated by different restriction endonucleases creates a sequence at the junction which is recognized by one of the restriction endonucleases.


Identification of prekallikrein and high-molecular-weight kininogen as a complex in human plasma.

Prekallikrein and high-molecular-weight kininogen were found associated in normal human plasma at a molecular weight of 285,000 as assessed by gel filtration on Sephadex G-200. The molecular weight of prekallikrein in plasma that is deficient in high-molecular-weight kininogen was 115,000. This prekallikrein could be isolated at a molecular weight of 285,000 after plasma deficient in high-molecular-weight kininogen was combined with plasma that is congenitally deficient in prekallikrein. Addition of purified 125I-labeled prekallikrein and high-molecular-weight kininogen to the respective deficient plasma yielded a shift in the molecular weight of prekallikrein, and complex formation could be demonstrated by incubating prekallikrein with high-molecular weight kininogen. This study demonstrates that prekallikrein and high-molecular-weight kininogen are physically associated in plasma as a noncovalently linked complex and may therefore be adsorbed together during surface activation of Hageman factor. The complex is disrupted when these proteins are isolated by ion exchange chromatography.


Dichloromethane as an antisickling agent in sickle cell hemoglobin.

Microscopic studies of red cells from homozygous sickle cell patients show that dichloromethane does prevent sickle cell formation in vitro and does cause reversion of sickled cells to normal after exposure to dichloromethane. X-ray structural analysis of human deoxyhemoglobin crystals exposed to dichloromethane shows four unique binding sites. Arguments are presented to suggest that the binding site close to tryptophan 14alpha prevents the formation of helical polymers, i.e., prevent sickling.


Protein cleavage during virus assembly: a novel specificity of assembly dependent cleavage in bacteriophage T4.

Cleavage of precursor proteins occurs during assembly of numerous viruses. Seven bacteriophage T4 head-related proteins areknown to be cleaved during morphogenesis. Sequences surrounding the cleavage sites in T4 head precursors P23 and IPIII are reported here. We previously determined the sequences of precursor and processed forms of IPII and IPI. Cleavage occurs at a glutamyl-alanyl bond in each protein. By comparison of sequences around five cleaved and four uncleaved Glu-Ala bonds in head precursors, it appears that cleavage is limited to the Thr or Ala, and X2 to hydrophilic residues. The results suggest the viral-induced assembly protease recognizes and cleaves an extended primary structure in the structurally dissimilar precursors.


Rat sympathetic neurons and cardiac myocytes developing in microcultures: correlation of the fine structure of endings with neurotransmitter function in single neurons.

Microcultures containing single sympathetic principal neurons and small numbers of dissociated heart myocytes were prepared from newborn rats. After the transmitter properties of the neuron were studied by electrophysiological experiments, the microculture was examined with the electron microscope. Single neurons of either putative cholinergic or putative adrenergic character made morphological synapses on themselves (autapses), although only cholinargic autapses were detected electrophysiologically. Numerous axonal varicosities were present adjacent to the myocytes but no synaptic specializations were evident. After permanganate fixation to localize endogenous norepinephrine, the endings of neurons which appeared to secrete catecholamines contained many small granular vesicles, while the endings of neurons which appeared to secrete acetylcholine contained none. The endings of neurons which apparently secreted both catecholamines and acetylcholine contained only occasional small granular vesicles.


Renal CO2 production from glutamine and lactate as a function of arterial perfusion pressure in dog.

The energy cost of renal function in the intact kidney of the dog was assessed at a series of arterial perfusion pressures. Pressure was varied by partially inflating a balloon at the tip of a catheter positioned in the aorta above the origins of the renal arteries. Either L-[U-14C]-lactate was infused intravenously in tracer amounts throughout each experiment. Total renal CO2 production and 14CO2 production from each isotope permitted assessment of total renal oxidative metabolism and the proportions derived from the two major substrates of the kidney. Stepwise inflation of the aortic balloon progressively lowered glomerular filtration rate, renal blood inflow, filtered and consequently reabsorbed Na+, total renal CO2 production, and 14CO2 derived from glutamine and lactate. The percent of total CO2 derived from lactate decreased more or less in proportion to the decrease in percent of total CO2 produced. Results were consistent with the view that reabsorption of sodium is the major energy sink of the kidney. They suggest that the oxidation of glutamine supplies energy for tubular transport and basal demands such as synthesis of hormones and maintenance of structure, whereas the oxidation of lactate supplies energy mainly for transport activities.


Ear and hearing in Sphenodon punctatus.

Observations on Sphenodon punctatus have revealed new features of the anatomy of the ear,and measurements in a living specimen by means of cochlear potentials show the form and level of this ear's performance in sound reception. For an animal lacking an external ear opening and a functional tympanic membrane, the sensitivity of from 100-900 Hz is surprisingly good in low tones with peak response around 200-400 Hz. The inner ear is well developed, with a tectorial membrane connected to a tectorial plate that extends throughout the cochlea. The best region of sensitivity agrees well with the main frequency components of the animal's vocalizations.


[Altered states of consciousness induced by N,N-dimethyltryptamine (DMT)].

In a controlled study on 38 volunteers the effects of 250 mcg/kg N,N-Dimethyltryptamine (DMT) i.m. were assessed. 26 subjects received DMT and 12 placebo. The altered states of consciousness and the somatic changes were measured by several questionnaires administered after the experiment. In spite of the low dose as compared to previous studies significant differences to placebo were found in the following syndromes of altered states of consciousness: visual hallucinations rep. illusions, impairment of memory and attention, changes of body image, depersonalization syndrome, derealization syndrome, euphoric state, anxious-depressive state and delusion. The somatic side effects were mainly subjective respiratory troubles, dizziness and weakness.


Motilin-induced electrical activity in the canine gastrointestinal tract.

Myoelectric activity induced by a synthetic analogue of the duodenal polypeptide motilin, was studied in isolated vascular-perfused canine duodenum and stomach, and in conscious dogs with serosal electrodes implanted in the stomach and the small intestine. In the isolated preparation, the duodenum was found to be four times as sensitive as the antrum to the polypeptide, showing a dose-dependent increase in spike activity within two minutes after administration of the polypeptide. By contrast, in the conscious fasted animal, the only response to motilin, above a threshold dose, was the interpolation of a premature migrating myoelectric complex in the spontaneous interdigestive sequence, appearing fifteen to twenty minutes after the start of infusion. Since the essential difference between the ex vivo and the intact intestine was the preservation of efferent and afferent nervous connections in the latter, it seems that in the conscious animal, the response to exogenous motilin is modulated by the innervation of the intestine, or, alternatively, motilin interacts with the centre controlling the pattern of motor activity in the small intestine rather than directly with smooth muscle. The latter hypothesis is supported by the observation that motilin had no effect on the motor activity of the small intestine during the infusion of pentagastrin which abolishes spontaneous migrating myoelectric complexes.


Syntheses of motilin analogues.

According to a first suggestion for the primary structure of the gastrointestinal hormone motilin, two analogues containing norleucine and leucine instead of methionine in the sequence position 13 (primarily called 13-norleucine and 13-leucine-motilin) have been synthesized. Both synthetic peptides were biologically active in equivalence to the natural product. A correction of the proposed amino acid sequence became necessary after rechecking the results by comparison with the synthetic materials. The two analogues must therefore correctly be named 13-norleucine-14-desamidomotilin and 13-leucine-14-desamido-motilin.


Potentiation between 13-Nle-motilin and acetylcholine on rabbit pyloric muscle in vitro.

The interaction of 13-nle-motilin-a synthetic analogue of the natural polypeptide-with acetylcholine was studied on rabbit isolated pyloric sphincter in vitro. Adding subthreshold doses of 13-nle-motilin reduced the calculated acetylcholine dose for half maximal contraction from 3.68 to 1.33 X 10(-6) g/ml and increased the calculated maximal response by 15.3%. Thus 13-nle-motilin caused potentiation of the acetylcholine response. Since 13-nle-motilin induced increase of endogenous acetylcholine levels could be excluded, a direct action of motilin on or in the smooth muscle cell is suggested. The results are compatible with the view that in vivo subthreshold doses of motilin may affect cholinergic driven pyloric motor activity.


Measurement of human plasma motilin.

A specific radioimmunoassay has been developed for human plasma motilin. No cross reaction was seen with other gut hormones and only a single major peak of motilin immunoreactivity was found in plasma and gut extracts after gel chromatography. The motilin content of the human duodenum was 165.7+/-15.9 pmol/g wet weight and jejunum 37.5+/-2.8 pmol/g with negligible amounts in the rest of the gut. Fasting plasma motilin concentrations in 100 healthy subjects ranged from less than 5 to 300 pmol/l (mean 72 pmol/l).


Release of motilin in man.

The effects on motilin release of various stimuli including an ordinary hospital lunch and ingestion of equicaloric amounts of protein (steamed cod), fat (double cream), or carbohydrate (glucose solution), and intraduodenal instillation of acid (0.1M HCl) and alkali (0.3M tris buffer, pH 10.2) have been investigated in healthy volunteers. Duodenal acidification resulted in a 90% rise of plasma motilin while after intraduodenal instillation of alkali motilin fell. No significant change was seen after a normal hospital lunch and the protein meal, and a small fall was observed after glucose. By contrast, after ingestion of 60 g fat motilin showed a peak increase of 65% at 30 minutes and was still significantly elevated at 60 minutes. Exogenous motilin has been reported to delay gastric emptying and this is also seen after duodenal acidification and fat ingestion. We conclude that motilin may be released physiologically by these stimuli and mediate their effects on gastric emptying in man.


Motilin effects on gastrointestinal motility and lower esophageal sphincter (LES) pressure in dogs.

Natural porcine motilin induces phasic contractions of the lower esophageal sphincter in dogs. These contractions are related to gastric contractions, which have the characteristics of interdigestive-motility patterns. Duodenal alkalinization produces an insignificant LES pressure increase after 5 minutes. No effect of motilin was observed when using isolated canine muscle strips.


Intravenous 13-Nle-motilin increases the human lower esophageal sphincter pressure.

To elucidate whether, in principle, motilin could serve a role in LESP regulation, the effects of 13-norleucine-motilin (13-nle-m)-synthetic analogue of motilin and biologically just as active as the natural polypeptide-on LESP were investigated in normal subjects. LESP was monitored with the continual withdrawal method. Sets of tests: (1) i.v. pulse doses of 13-nle-m (0.05, 0.1, 0.2, and 0.4 mug/kg) were given to 6 subjects in random order on different days, (2) i.v. bolus injections of 0.6 mug/kg pentagastrin were given to elicit maximal LES contractions, (3) i.v. infusions of 13-nle-m (0.1, 0.2, and 0.4 mug/kg-h; doses doubling every 30 min) were used in 7 individuals, and (4) the effect of atropine infusion of 13-nle-m-stimulated LESP was studied in 6 subjects. (1) Graded i.v. pulse doses of 13-nle-m caused LESP to increase dose-dependently with maximum pressures exceeding basal levels by about 160% (p less than 0.01). After each bolus injection, peak values were achieved within 1-2 min followed by a steady decrease in LESP. (2) Maximum response to 0.4 mug/kg 13-nle-m was about 65% of that to 0.6 mug/kg pentagastrin. (3) i.v. infusions of varying doses of 13-nle-m caused a significant and dose-dependent increase in average LESP. (4) The stimulating effect of an i.v. pulse dose of 0.1 mug/kg 13-nle-m on LESP could be suppressed by concomitant atropine. the human LES is responsive, indeed, to exogenous motilin.


Effect of 13-Nle-motilin on small intestinal transit time in healthy subjects.

In 6 female subjects without gastrointestinal diseases, 13-norleucine motilin (13-Nle-M) synthetic and biological analogue of the duodenal polypeptide, motilin, caused acceleration of intestinal transit time. Intravenous infusion of 0.4 mug/kg-h of 13-Nle-M reduced mean transit time by 50 percent. No side effects occurred during infusion of the polypeptide. Radiographic appearance of small intestinal peristalsis and mucosal relief was not influenced by 13-Nle-M.


Motilin-induced mechanical activity in the canine alimentary tract.

Gastrointestinal contractile activity from the lower esophageal sphincter to the terminal ileum in the conscious dogs was continuously recorded on a multi-channel polygraph for several weeks by means of chronically implanted strain gage force transducers. It was found that the 24-hour gastrointestinal motor activity consisted of the two different major patterns; the digestive and interdigestive patterns. The interdigestive motor activity was characterized by a cyclic recurring, caudad-moving band of strong contractions interrupted by long lasting motor quiescence. When one band of strong contractions reached the distal ileum, another developed in the LES, stomach and duodenum again and propagated in a caudad-direction. Such recycling episodes repeatedly occurred until the next meal. After ingestion of food, gastrointestinal motor activity was continous and such characteristic interdigestive patterns were not observed. Synthetic motilin, 0.1-2.7 mug/kg/hr, was assayed for its motor stimulating activity in the both states. In the digestive state, an i.v. infusion of motlin had no influence upon the motor activity even if the dose was increased up to 6.0 mug/kg/hr. On the other hand, when motilin was infused during the interdigestive state, it induced a pattern precisely like the naturally-occurring interdigestive contractions. Not only the naturally-occurring contractions but also motilin-induced contractions were strongly inhibited by the ingestion of food or an i.v. infusion of pentagastrin (0.2-1.8 mug/kg/hr). Duodenal acidification (0.1 N HC1, 3-16 ml/kg/hr) in the interdigestive state disturbed or inhibited the regular cycle of the natural contractions but was counteracted by exogenous i.v. infusion of motilin. These findings strongly suggest the view that the interdigestive gastrointestinal motor activity is at least in part regulated by circulating motilin concentration in the blood, however, its cyclic recurring, caudad propagating mechanism may be controlled in part by the nervous system. Motilin is the only substance known to be active during the interdigestive state and therefore may be called the interdigestive hormone.


[Human non-epithelial tumors in "nude" mice: morphology and growth characteristics].

Morphology and growth characteristics of an osteosarcoma and a glioblastoma are described after direct transplantation in nude (thymusless) mice. In osteosarcoma neither characteristic had changed after 14 months' observation. In contrast, some of the glioblastoma transplants (22 months' observation) showed dedifferentiation of morphology and grew faster than others derived from the same biopsy. The possible reasons for the different growth pattern of the two tumors are discussed.


Meningitis caused by Rhodotorula.

A case of rhodotorula meningitis in a 21 year old male compromised with acute lymphoblastic leukemia is reported. The yeast was identified as Rhodotorula rubra (Demme) Lodder.


[Autologous cartilage grafts for rhinoplasties in patients with clefts].

Almost any forms of complete clefts require a rhinoplasty in spite of good primary results with modern methods of operation in the labial region. The final correction is performed after the fifteenth year of life. The existent supporting tissue is often inadequate and will yield no optimal result if local reconstruction alone is performed. Transplantation of autologous cartilage to the side of the nose and to the columella may compensate for the deficit, the columella cartilage chip permitting to erect the nose, which gives favorable aesthetic and functional results. Consequently, rhinoplasty is recommended for certain unilateral complete clefts and in any case for bilateral complete clefts.


[Results in the treatment of lateral middle face fractures].

During 1960-1973, 90 patients with lateral midface fractures were treated at the Rostock University Clinic and Policlinic of Stomatology. 68 patients underwent a clinical and radiographic follow-up examination. The intra-antral operation methods had yielded better results than the extra-oral treatments. To reduce late sequelae which are observed also in patients for whom a surgical approach had not been indicated, the authors recommend an exact diagnostic evaluation of the lateral midface fractures and a close interdisciplinary co-operation of the oral surgeon and the ophthalmologist.


[Experiences with linear and multi-dimensional tomography and zonography in the radiodiagnosis of the temporomandibular joint].

A Multigraph 2 served to compare linear and elliptic tomography with linear and circular zonography as to their diagnostic values in the examination of the temporomandibular joint. The contrasts and the blurring effects of the different forms of layers are studied with regard to the appreciation of the structures and contours of the joint-forming components. The linear zonography is considered the method of choice, mainly because it gives sharp contrasts.


[Indications for treatment of mandibular fractures in the adult].

From the many kinds of treatment which are indicated in the literature, the authors selected for presentation those methods which have proved useful at the Rostock University Clinic and Policlinic of Stomatology, during many years, in managing mandibular fractures, their indications being precisely established. The therapeutical measures still centre on conservative methods, modern operation techniques being optimal complements. If surgical management of the fracture is necessary, a stable osteosynthesis technique should be used on principle, condylar process fractures being excepted.


[Group treatment of children with speech disorders].

Group instruction of children with speech disorders due to clefts has certain advantages over individual instruction. These advantages ares presented from the viewpoint of logopaedia and corroborated by experience with 77 children treated up to now. More rapid and better speech rehabilitation associated with a decrease in indication for speech-improving surgical interventions are the outstanding results of group instruction. It comprises early instruction, rehabilitative logopaedia (courses and individual instruction) and after-care with directives for the parents, and concerns the age groups 0-3, 3-6 (7) and 6 (7)-18 years.


[Diagnosis of temporomandibular joint diseases in the ambulatory practice].

The temporomandibular joints of 977 students of the Rostock University were examined clinically and radiographically. Objective findings (laterodeviation of the mandible, crackling noises of the joint, radiographic changes of the position of the condyle) were frequently obtained, whereas subjective complaints (arthralgia, crackling noises of the joint) were rare. Only the occurrence of both symptom complexes requires an exact diagnosis and therapy of the temporomandibular joint disease after optimal oral rehabilitation.


[Epithetic treatment of facial defects].

The author deals with the aetiology and location of facial defects treated prosthetically during 1974-1975. Treatment methods currently used at the Rostock University Clinic and Policlinic of Stomatology are presented with special regard to constructions developed in this clinic. The importance of the choice of an appropriate material and of the possibility of secure anchoring is pointed to. In spite of certain disadvantages which should not be underrated, facial prostheses have proved useful for temporary treatment and also for definite treatment


[Correlations between chronic liver diseases and periodontal diseases with special reference to animal experiments].

The purpose of the present paper was to investigate possible relationships between chronic liver diseases and marginal periodontal diseases, using clinical and radiographic methods as well as animal experiments. The periodontal conditions of 100 patients with histologically confirmed chronic hepatopathies were compared with those in a control group of same size. The results of these studies testify unequivocally to unfavourable conditions in the group of hepatopaths. This finding is corroborated and complemented by subsequent animal experiments. The difference in the extent and intensity of the periodontal alterations between a group of Wistar rats with experimentally induced hepatopathies and a control group was statistically significant. These results permit the conclusion that an aetiologic relation between chronic hepatopathies and marginal periodontal diseases may be assumed.


[Tooth supporting structure and its importance for the regular development of the dentition and resulting therapeutic recommendations for practice].

The authors emphasize the importance of the supporting area to the regular development of the dentition and describe possibilities for preserving the deciduous teeth until the physiological change to the permanent dentition occurs. The change to the permanent dentition should be guided by a competent evaluation of space supply and space need to avoid expensive orthodontic measures. The supporting area analysis according to Moyers has been used with success to estimate whether the space in the supporting area will be sufficient for the permanent teeth.


[Timing of the orthodontic treatment in patients with cleft lip and cleft palate].

There is now a general concensus of opinion that the specific care of patients with congenital clefts should be performed in the framework of their rehabilitation in large centres. The values of timely and competent care is deduced from results obtained from 100 orthodontic patients. In cleft patients orthodontic treatment must begin several years earlier than in patients without clefts.


[Working time analysis in conservative dentistry (dental filling therapy)].

The purpose of the present paper was to determine the time required for filling therapy. The authors deal briefly with the subdivision of time adopted for the present study. Conclusions as to planning in dental practice may be drawn from the results obtained only if values determined by different dentists are available for comparison.


[Epidemiologic studies. I. Secondary caries in tooth areas restored by silver-tin-amalgam, silicate cement or inlays].

On the basis of epidemiologic studies on 10 106 sugjects from the population of the town of Rostock, the authors deal with the frequency of filled tooth areas and their affection by secondary caries with special regard to filling materials (silver-tin amalgam, silicate cement, inlay). The low frequency of secondary caries in tooth areas restored by means of inlays is noteworthy. Finally, the authors give recommendations for practice.


Further observations on canine spirocercosis in Kenya.

The close association of the parasite Spirocerca lupi with oesophageal sarcomas suggests aetiological involvement of S lupi. Further investigations may yield results of significance with respect to comparative oncology. This paper records detailed observations made over an 11 year period, on the incidence and pathological variations of S lupi infections in Kenya.


[Humoral immunity in human sarcomas].

Studies on humoral immunity were performed in sarcoma patients before, during and after the treatment. Cytotoxic test was carried on with target cells of human mesenchymoma stable line. The activity of serum and its immunoglobulin fractions in 15 patients with soft tissue sarcoma and in 10 patients with congenital sarcoma was studied. It was found that 19S fraction of patient's blood serum contains cytotoxic antibodies. 7S fraction was permanently inactive. The whole serum was cytoloxic before the treatment in 8 of 12 patients with soft tissue sarcoma. Among 20 healthy donors only 3 were active. There was revealed a possibility of strong specific binding of 19S immunoglobulins (and more rarely of 7S immunoglobulins) with target-cells surface. It evidences the capacity of immunoglobulins to render not only cytotoxic action but also presumably, a blocking effect. Irradiation treatment in doses of 1800-9000 rad fail to diminish the cytotoxic activity of the whole serum and its 19S fraction.


[Hereditary predisposition to oncological diseases in leukemia patients].

Study on the genealogy of 671 patients with hemoblastosis has evidenced a more frequent incidence of malignant neoplasms in the families of patients with chronic lympholeucosis, erythremia and lymphogranulomatosis compared with the families of practically healthy persons. Whereas this regularity is not revealed in the families of patients with acute forms of leucosis and chronic myeloleucosis.


[Hepatitis-B-surface-antibodies (detection, incidence, clinical importance)].

The AusRIA 2 test has been modified for HBs antibody detection. This technique is about 7 to 8 dilution steps more sensitive for antibody detection than the IPE. Using this modified radioimmunological technique investigations have been carried out on blood donors, patients with acute and chronic liver disease and on haemophiliacs. An HBs antibody incidence of 11% was found among voluntary blood donors. Intensive clinical investigation of blood donors positive for HBs antibodies by IPE demonstrated that the Serum GOT was elevated in 11% of cases and the liver biopsy showed histological changes of different severity in 16 out of 22 cases. Investigation of 22 cases of acute HBs antigen-positive hepatitis confirmed that nearly all the patients developed HBs antibodies within 10 weeks following the disappearance of HBs antigen. The HBs antibodies persist over years. The appearance of HBs antibodies after an acute HBs antigen-negative hepatitis can be taken as an indication of a hepatitis-B virus infection also in these cases. Among 22 HBs antigen-negative chronic hepatitis cases, HBs antibodies were detectable in 52%. Sera of 111 patients with HBs antigen-negative liver cirrhosis of varying aetiology showed HBs antibodies in 29.7% of cases. The incidence was higher in males. HBs antibodies were found in 98% of patients with haemophilia. These results reveal new aspects with regard to the importance of the hepatitis-B viurs, especially in chronic liver disease. Apart from a description of the newly-developed HBs antibody test and a discussion of the results obtained using this technique, a survey is given of the importance of HBs antibody determination by means of sensitive methods for clinical and epidemiological purposes.