The temperature of the gingival sulci.

The interproximal sulcular temperatures of the central, cuspid and the first molar regions of both jaws of 28 adults were recorded with a thermistor probe. The mean sulcular temperatures were 1.80 to 2.90 degrees C lower than the mean sublingual temperature. In both jaws the lowest temperature was recorded in the anterior region and the highest in the molar region. The temperature increased from the anterior to the posterior region on both buccal and lingual sides of both arches. The sulcular temperatures of the lower arches were higher than those of the upper arches. Further, analyses of the data of each individual subject showed interesting differences between the male and the female subjects. This work suggests that studies on dental plaque and on the growth and metabolism of microorganisms of the gingival sulci should consider the lower temperature of the gingival sulci and the regional temperature differences within the oral cavity.


Scanning electron microscopy of epithelial cells grown on enamel, glass and implant materials.

The purpose of the present study was to examine with scanning electron microscopy gingival epithelial cells grown in cell culture on tooth enamel, glass, Vitallium, titanium and vitreous carbon. SGL (Smulow-Glickman) gingival epithelial cells were grown for 5 days and processed using a critical point drying apparatus. Scanning electron microscopy carried out at X 1500 magnification revealed that the gingival epithelial cells gres equally well on all materials on either smooth or rough (sand-blasted) surfaces.


Periodontal findings in diabetic and nondiabetic patients.

This study was conducted to determine the possible influence of diabetes on the pathogenesis of periodontal disease. A total of 148 patients, 120 females and 28 males, were surveyed. Their ages ranged between 9 and 50 years, with an average age of 30. The experimental group consisted of 83 diabetics and there was a control group of 65 nondiabetics. Both groups were divided into patients under and over the age of 30. The results showed: 1. Loss of attachment was higher in the over-30 diabetic group in the presence of similar local factors. 2. A higher Gingival Index was reported in diabetics of the combined age groups than in the controls (P less than 0.05). 3. The Plaque and Calculus Indices did not differ significantly between the diabetic and control subjects. 4. The correlation between the Plaque Index and loss of attachment in diabetics was the most relevant of the correlation analyses. The correlation between the gingival inflammation and loss of attachment indices in the combined diabetic group was also significant. 5. In both groups, diabetics and controls, periodontal destruction increased significantly with age. 6. Juvenile diabetics with severe periodontal disease, as well as others with normal periodontal structures, were found in the course of this study. These findings coincided with the presence or absence of local factors.


Venery and Vincent's? 15 case reports and discussion.

Fifteen case reports of necrotizing gingivitis in young adult white male servicemen of low socioeconomic background, low pay grade, and in the first few years of enlistment have been presented. Stochastic review of data indicates that a behavior pattern of promiscuous sexual intercourse may be another important predisposing factor prior to the onset of this acute disease. Military personnel who are confined during training or in operations where open social contacts are not possible do not seem to have as high an incidence as those free for time off the base. The case pattern for naval personnel at Great Lakes is similar to that of other naval personnel who sustain gonorrheal infections. The behavioral patyern of young adult males therefore may account for a high incidence in a population which is usually in good health. Preliminary microbiological samplings from the necrotic lesions of the subjects reported upon were negative for the isolation of incriminating microorganisms. In the absence of a known etiologic agent, and with only patient's testimony as evidence, the clinician should not draw conclusions, but he should be aware of a possible venereal relationship with necrotizing gingivitis in young adults.


The incidence of transient bacteremia during periodontal dressing change.

Twenty patients undergoing treatment for periodontal disease and not receiving antibiotics, volunteered to donate blood for culture studies to determine the incidence of transient bateremia during the dressing change and suture removal 1 week after periodontal surgery. Each patient contributed 20 ml of blood prior to the dressing change and an additional 20 ml during suture removal. The samples were cultured both aerobically and anaerobically. Bacteria were demonstrated in five out of 20 postoperative cultures (25%). This incidence approached statistical significance at the 0.05 level using Chi-square analysis with a Yates correction. All species were identified as belonging to the genus streptococcus. None of the blood specimens obtained prior to dressing change exhibited bacterial growth. Although the incidence of bacteremia in this study was not statistically significant at the 0.05 level, it may be clinically significant that five out of 20 patients demonstrated transient bacteremia. Commercial materials and equipment are identified in this report to specify the investigative procedures. Such identification does not imply recommendation or endorsement or that the materials and equipment are necessarily the best available for the purpose. Furthermore, the opinions expressed herein are those of the author and are not to be construed as those of the Army Medical Department.


Spontaneous arrest of advanced periodontal disease without treatment: an interesting case report.

A 48-year-old female patient presented with advanced periodontitis but was unable to proceed with periodontal therapy. After ten years of absence, her periodontal status appeared unchanged, if not slightly improved, despite the total lack of any dental or periodontal care. Studies on the biologic behavior of periodontitis are severely lacking and would appear to be a logical area for future epidemiologic surveys.


Effects of tobacco smoking on plaque development and gingivitis.

A study was undertaken to test the hypothesis that patients who smoke tobacco have a more rapid rate of plaque deposition and development of gingivitis than those patients who do not smoke tobacco. Twenty subjects participated in this study, their age range was 17 to 30 years. Ten were smokers and 10 were nonsmokers. After an initial thorough removal of all deposits, oral hygiene measures were stopped for 10 days. On days 3, 7 and 10, plaque levels were evaluated using the Plaque Index and the gingival status was evaluated using the Gingival Index. Samples of plaque were stained by the Gram technique and examined microscopically. Plaque levels appeared to be higher in smokers than nonsmokers but the differences were not statistically significant. No consistent differences were evident in the gingival status of the two groups. Microbiological analysis showed a statistically significant increase in the percentage of Gram-positive bacteria to Gram-negative bacteria in the smokers as compared to the nonsmokers on day 3, however these differences were not maintained in the plaque samples taken after the 3rd day.


The relationship between attachment height and attachment area of teeth using a digitizer and a digital computer.

Nine lower first bicuspid teeth were mounted in blocks of plastic and their roots were serially sectioned and photographed. Data from the photographs were compiled by a digitizer and a digital computer, which calculated the cumulative root surface area for each millimeter of root height. From these data, three variables, which relate root surface area to root height, were calculated. It was found that if one-half of the height of attachment to the root were lost due to periodontal disease, a mean of 61.5% of the actual attachment area to the root is lost. If a mean of 5.72 mm of root attachment height is lost, or if a mean of 60.6% of the same root height remains, only one-half of the total root attachment area remains to provide tooth support.


Correction of prognathism with fixed and removable partial dentures.

Prognathism in those patients for whom surgical orthodontic procedures are contraindicated can be successfully treated by the use of fixed and removable partial denture prosthodontics. Careful neuromuscular evaluation of the patient is necessary for the success of the treatment rendered. The nonsurgical treatment of prognathism by this method was described.


Intracoronal pressure during crown cementation.

A model system was developed which recorded the intracoronal pressure during crown cementation at three locations simultaneously. Peak pressures and residual pressures were greatest with zinc phosphate cement. The zinc oxide-eugenol cement generated the smallest amount of peak and residual pressures. The polycarboxylate cement exhibited an intermediate pressure intensity. The uneven intracoronal pressure in the cement suggests a complex flow pattern capable of developing the separation of phases that earlier work reported. However, the small residual pressure indicates that these internal back pressures appear to play a limited role in preventing a complete seating of a crown.


Dentinal crazing and interpin distance.

All three types of self-threading plus cause dentinal crazing. The frequency and degree of damage done to the dentin varies significantly between the three types of pins and depends upon the differences in the diameters of the drill and the pin. When two or more pins are placed in dentin, the potential for dentinal damage increases. Minikin pins (0.019-inch diameter) caused the least damage, in terms of both degree and frequency. The optimum and safe interpin distance using Minikin pins suggested by this study is 3 mm. Minim and Regular pins (0.023- and 0.031-inch diameters, respectively) caused more injury than Minikin pins. The Regular pins showed more damaging effects on dentin than Minim pins, both in terms of degree and frequency. On the basis of this study, the minimum interpin distance using Minim or Regular pins should be 5 mm. These minimum interpin distances are applicable only in situations where the dentin is not dehydrated or embrittled due to endodontic treatment. In teeth that have been endodontically treated, it would be advisable to use only the smallest self-threading pins and possibly increase the interpin distance if two or more pins are to be used.


Pressuring techniques and cement thickness for cast restorations.

1. Dynamic pressure produced thinner cement films than static pressure. The cement film was thinner with vibratory pressure than with the mallet. The thickness was slightly less with vertical vibration than with horizontal vibration. Horizontal vibration seemed preferable because it could be used with increased pressure without causing trauma or pain. 2. The combination of static pressure followed by dynamic pressure produced thinner cement films than any individual pressuring technique. 3. The optimal technique for clinical use is to seat the casting by finger pressure and then apply horizontal vibration under hand pressure.


Finished surface texture, abrasion resistance, and porosity of Aspa glass-ionomer cement.

1. With the finishing agents tested Concise had a smoother surface texture than Aspa. 2. The smoothest surface was on Concise polymerized against a Mylar matrix strip. The smoothest surface for Aspa was obtained with a silicon carbide disk. 3. Aspa abraded about three times as rapidly by volume as Concise when tested by a two-body abrasion method. 4. Significantly more air bubbles were entrapped by hand mixing within Aspa than within Concise. 5. Controlled clinical studies of the glass-ionomer cements are needed before they can be fully evaluated as restorative materials.


Effect of occlusal splints on TMJ symptomatology.

The clinical response of TMJ symptomatology to full-coverage occlusal splints, when used as the only means of treatment, was evaluated. The symptomatology recorded during the last postoperative visit was compared to the initial visit. The response of the different symptoms to the use of the occlusal splint was analyzed statistically using a chi-square test. A statistically significant difference (p = .03) was only found when comparing those groups having only pain or dysfunction symptomatology. The response favored the remission of pain. However, every symptom was improved with the use of an occlusal splint. It was concluded that: 1. Both pain and dysfunction symptomatology will benefit from the occlusal splint therapy. 2. The pain response will be significantly better than the dysfunction response when the patient is treated with an occlusal splint. 3. Eighty percent of the patients suffering from a TMJ syndrome will improve or be cured when the only form of treatment is the use of a full-coverage occlusal splint.


Instrumentation for placement of vitreous carbon endosseous implants.

The instruments required for placement, stabilization, and restoration of vitreous carbon endosseous implants are conventional in character and readily available. With the exception of extra-long burs for socket preparation, all instruments are normally available in dental offices. The surgery instruments should be rigorously sterilized prior to use, including the dental handpiece, burs, suction tip, etc. Gas sterilization techniques provide an effective means of sterilizing the surgical instruments without causing corrosion of burs and the handpiece.


Mirror system for profile photography.

A portable and collapsible mirror system has been described that enables both lateral profiles and anterior facial views to be recorded with a single photograph in a standardized and reproducible manner. Therefore, routine records and measurements can be made in the many branches of dentistry that plan and execute treatments which could change the facial form of the patient.


Alveolar bone loss in overdentures: a 5-year study.

The results of a 5-year clinical study show that patients treated with complete maxillary dentures and mandibular overdentures demonstrate less vertical alveolar bone reduction than patients with complete maxillary and mandibular dentures.


Characterization of two ceramic-base-metal alloys.

Compositions, microstructures, properties, and heat treatment characteristics of two ceramic-base-metal alloys were studied. The materials displayed significant compositional and structural differences. Both alloys were strengthened by precipitation hardening. Strength and rigidity of the nickel-chromium alloys suggest their potential usefulness in fixed prosthodontic procedures.


Alveolar ridge augmentation with tricalcium phosphate ceramic.

Tricalcium phosphate ceramic, with 50% porosity and 400 to 500 micrometer pore diameter, was used to augment the edentulous alveolar ridge of 10 adult mongrel dogs. The implants were evaluated histologically at different time intervals (7, 30, 90, 180, and 360 days). Preoperative and postoperative blood chemistry studies were also evaluated. The results showed that, other than for the expected acute nonspecific inflammatory response due to the surgery, the material was well tolerated by the tissues and was nontoxic. Bone and soft tissues grew into the pores, thereby creating an excellent biomechanical bond between the ceramic implant and surrounding structures. Preoperative and postoperative blood chemistry studies demonstrated no significant change.


Restoration of endodontically treated posterior teeth with amalgam.

A technique for restoring endodontically treated posterior teeth has been presented. The pin-amalgam restoration may be used as an acceptable alternative to the cast restoration for situations where a cast restoration is not indicated.


Mechanical and systems approach facilitating facial prosthesis production.

A method of facilitating facial prosthesis production using specially designed equipment and a color notation record has been described. Application to facial and auricular prosthesis production has been discussed. Advantages in time saved and staff utilization have been realized through the use of this approach.


Epidemiologic studies on prevalence and etiology of functional disturbances of the masticatory system.

Clinical observations and data from the literature indicate a high prevalence of functional disturbances of the masticatory system, especially TMJ dysfunctions and bruxism. Clinical observations indicate that these disturbances are caused mainly by malocclusion, iatrogenic factors, and increased psychoemotional tension. On the basis of epidemiologic studies on five populations of different ages, the prevalence and etiology of functional disturbances of the masticatory system were analyzed. The need for causal local prophylaxis of functional disturbances was postulated.


Wound healing of endosteal vitreous carbon implants in dogs.

Endosteal vitreous carbon implants are biocompatible and were well-tolerated by the alveolar process of dogs but were not accepted by the gingival margin and the mucosa. A continuous gingival recession with 2 to 3 mm sulcus depth was not similar to that around adjacent natural teeth. There was no epithelial attachment around the neck of vitreous carbon implants, and there was very little or no resistance to probing. The feasibility of using vitreous carbon as it presently exists for the maintenance and preservation of alveolar bone is unfavorable and should be revised. Endosteal vitreous carbon implants require more intense laboratory and clinical studies. Therefore, the practical value of the vitreous carbon implant is questionable, and further investigations are needed before vitreous carbon can be declared acceptable in clinical dental practice.


Residual alveolar ridge atrophy: classification and influence of facial morphology.

A method for grading residual alveolar ridge atrophies of edentulous maxillae and mandible has been devised for men and women. Comparisons were made in women and in men between the degree of atrophy and the vertical facial morphology. The study suggests some relationship between the total facial height (TFH), the vertical facial type determined by the Frankfort horizontal mandibular plan (FMA), and the atrophy of the alveolar ridges, especially for the mandible. Certain practical applications of these findings were suggested.


Mycoplasma salivarium in the blood of a child with leukemia.

Mycoplasma salivarium was recovered from the blood of a five-year-old girl who had leukemia and subsequently developed pneumonitis. The patient's pneumonitis failed to respond to nafcillin, a cell-wall-active antibiotic, but eventually she recovered from the pneumonia after a regimen of erythromycin. Sputum, oropharyngeal, and nasopharyngeal cultures revealed normal bacterial flora; a blood culture was negative for bacteria. Throat and sputum cultures were negative for mycoplasma; however, M salivarium was recovered from the patient's blood. The patient had a cold hemagglutinin titer of 1:250.


Genealogy of cancer in a family.

Three brothers had separate childhood cancers--osteogenic sarcoma, acute lymphoblastic leukemia, and bilateral malignant neurilemoma. Comprehensive family history showed a total of 16 cases of cancer among the descendants of the proband's great-great-great-grandmother, including a previously unsuspected cluster of similar neoplasms in an distant branch. The constellation of tumors in the family included bony and soft-tissue sarcomas, brain and neural tumors, leukemia, and breast carcinoma, occurring in a pattern suggesting the action of an incompletely penetrant autosomal dominant gene with pleiotropic effects. In some cases the genetic predisposition may have interacted with environmental determinants to produce particular tumors.


Retinoic acid-binding protein in human breast cancer and dysplasia.

Seventy-five specimens of human breast tissue were checked for the presence of cellular retinoic acid-binding protein (cRABP). Fifty-two percent of the primary carcinomas and 43% of the dysplastic breast lesions (stage MII) contained detectable amounts of crabp, whereas no cRABP was found in normal tissue. Sucrose gradient centrifugation and electrophoresis on agarose were used for analysis of the presence of cRABP. The cRABP of human origin (normal uterus and neoplastic mammary tissue) differed in its mobility in agarose electrophoresis from that of rat testis cRABP.


Geographic patterns of prostate cancer in the United States.

Age-adjusted rates of mortality from prostate cancer during 1950-69 were correlated by race with demographic, industrial, and agricultural data from 3,056 U.S. countries. Mortality among nonwhites was 50% higher than that among whites in all parts of the country where blacks comprise most of the nonwhite population. The rising rate associated with population density among nonwhites, but not whites, suggested that environmental exposures related to urban living may account for the predisposition of American blacks to prostate cancer. Despite a clustering of counties with elevated mortality in certain North Central and Northeastern States, the geographic variation among whites with prostate tumors was considerably less than that among whites with other tumors. Mortality was elevated in counties with a high percentage of residents of Scandinavian descent, in counties with metal-using and textile industries, and in regions with high consumption of high-fat foods.


Demonstration of antibodies in patients' sera, directed against nonspecific cross-reacting antigen.

Nonspecific cross-reacting antigen (NCA), which strongly cross-reacts with carcinoembryonic antigen, was demonstrated to be an autoantigen. Antibodies directed against NCA were shown in different groups of patients, but high titers (greater than 1/64) were found only in cancer patients. A correlation between tumor mass, antigen load, and antibody titer apparently existed. Sera obtained from patients preoperatively and postoperatively differed significantly (P greater than 0.01) in the sense that titers were high only in sera sampled after the patients were treated. Nevertheless, the formation of these antibodies cannot be considered a cancer-specific phenomenon because of their existence also in patients with nonmalignant diseases.


3-Hydroxyxanthine: transplacental effects and ontogeny of related sulfate metabolism in rats and mice.

The ontogeny of sulfate metabolism related to the metabolic activation of the carcinogenic purine N-oxide 3-hydroxyxanthine (3-OH-X) was studied in noninbred Sprague-Dawley rats. Sulfotransferase activity toward 3-OH-X was detectable in most fetal livers near term at about 25% of adult values and increased slowly after birth. This activity was also present in placentas. Compared to 3-OH-X sulfotransferase, sulfotransferase activity toward p-nitrophenol was lower in fetal livers and was not detected in placentas. Sulfohydrolase activity toward 3'-phosphoadenosine-5'-phosphosulfate was higher in fetal and newborn livers and in placentas than in adult liver. In a parallel transplacential carcinogenicity assay, a low but significant percentage of male rats exposed as fetuses to multiple high doses of 3-OH-X developed single liver carcinomas. After the lowest transplacental dose, the incidence of degenerative kidney disease in old male offspring was significantly higher than that in controls. In an assay with mice, (C57BL/6 X BALB/c)F1 mice exposed transplacentally to 3-OH-X experienced significantly greater perinatal morality and fewer lung adenomas among the surviviors at 20 months of age than did the controls.


Increased incidence of mammary tumors in rats after direct or transplacental exposure to 3-hydroxyxanthine.

Rats were exposed directly or transplacentally to the carcinogenic purine N-oxide 3-hydroxyxanthine (3-OH-X). Among female noninbred Wistar rats given 3-OH-X sc, beginning at suckling or weaning ages, there was a significantly greater proportion of mammary tumor bearers and a higher mean number of mammary tumors per rat than among controls. This effect was seen even at low doses producing no other neoplasms such as hepatic carcinomas or fibrosarcomas and fibromas at the site of injection. Noninbred Sprague-Dawley rats, treated transplacentally with 3-OH-X by ip injection into pregnant females, also  also had a significantly greater incidence of mammary tumors than did controls.


Surface structure of fetal rat brain cells during neoplastic transformation in cell culture.

The surface microstructure of fetal rat brain cells undergoing neoplastic transformation in long-term cell culture after a single transplacental pulse of 75 microgram N-ethyl-N-nitrosourea/g body weight to the fetal (18th day of gestation) BD IX rat was investigated by scanning electron microscopy. After about 3 weeks of culture, N-ethyl-N-nitrosourea-pretreated fetal rat brain cells showed focal proliferation of neural cells on an underlayer of flat, epithelioid cells. The neural cells exhibited varying forms of numerous dorsal ruffles and an increased number of other surface microprojections. Between the 40th and the 100th day, nodules of bipolar and multipolar neural cells were observed with a complex surface microstructure including many blebs and ruffles and an increased number of microvilli. After 100-210 days, more rapidly proliferating, morphologically altered cells formed "piled-up" foci, which resulted in a homogeneous population of cells with numerous long microvilli, large ruffles, and blebs over the whole surface. The cells retained the same altered surface structure until tumorigenicity after reimplantation into the syngeneic host was first observed (approximately 273 days). Surface alterations characteristic of the neoplastic cells were thus observable more than 100 days before the cells became tumorigenic.


Concanavalin A-induced agglutinability of normal, preneoplastic, and neoplastic mouse mammary cells.

The concanavalin A (Con A)-induced agglutinability of normal, preneoplastic, and neoplastic mouse mammary epithelial cells was examined. Cells freshly dissociated from normal mammary glands, hyperplastic alveolar nodules, or primary mammary adenocarcinomas by collagenase digestion in the presence of bovine serum albumin were strongly agglutinated by low concentrations of Con A. After short-term culture in vitro, however, cells from all three types of tissue were only weakly agglutinated by Con A, as measured by both suspension and hemadsorption assays. By comparison, cells of three established mammary tumor culture lines agglutinated strongly in the presence of the lectin. Treatment of the normal, preneoplastic, and neoplastic mammary cells in primary cultures with either trypsin or collagenase had little or no effect on their agglutinability, whereas hyaluronidase significantly increased their reactivity. Studies with fluorescein-tagged Con A indicated that all three cell types were capable of binding the lectin. The results were consistent with previous evidence suggesting that neoplastic transformation of mouse mammary epithelial cells is not manifested in vitro by several of the alterations in growth patterns, intercellular interactions, and surface properties that usually accompany transformation of fibroblastic cells.


Cytologic appearance of cells dissociated from rat colon and their separation by isokinetic and isopyknic sedimentation in gradients of Ficol.

Several methods for obtaining colon epithelial cells in suspension were compared. The largest number of epithelial cells per gram of colon was obtained in suspension when the colon was dissociated with 0.1% Pronase. Fivefold more cells per gram of tissue were obtained from the proximal 5 cm of colon than from the terminal 5 cm of colon. Several well-defined types of cells were observed in low frequency. They have not been described previously in normal colon. Suspensions of cells from colons of F344 rats always contained copious mucoid gel that was partially eliminated by washing the cells three times in culture medium with 10% fetal calf serum. Velocity sedimentation in a previously described isokinetic gradient of Ficoll in tissue culture medium permitted the separation of epithelial cells from lymphocytes and red blood cells. Type 2 cells, believed to be a subpopulation of epithelial cells, were obtained in a maximum purity of 95.7 +/- 1.2%. The frequency of 8 other cell types and their purification, when possible, are presented. Epithelial cells were separated from most bacteria and could be cultured with antibiotics after separation in the density gradient.


Morphologic and biochemical characterization of erythrophoromas in goldfish (Carassius auratus).

The properties of spontaneous cutaneous erythrophoromas that occurred in 17 adult goldfish (Carassius auratus) were described. This study was based on combined histology, cytochemistry, electron microscopy, and biochemical analysis. Tumors that varied from 0.4 to 2.7 cm in maximum diameter were located on various parts of the skin. As shown by light microscopy, tumors were composed of red- to orange-pigmented, dendritic, stellate, or spindle-shaped cells, which coalesced into an excrescence in the dermal layer. No metastasis was observed. Evidence of invasiveness in five examples and local recurrence in three examples indicated that some of these tumors were malignant. Electron microscopy revealed numerous round cytoplasmic organelles (pterinosomes), which measured 0.4--0.7 mu, and well-developed tubular, smooth endoplasmic reticulum in the tumor cells. Biochemical analysis showed that red pigmentation of tumor cells was imparted by pteridines and carotenoids, most of which were detectable in normal adult erythrophores. These data indicate that tumors were comprised of neoplastic erythrophores.


Pathology of esophageal neoplasms and associated proliferative lesions induced in rats by N-methyl-N-benzylnitrosamine.

Multiple squamous cell neoplasms of the esophagus were induced in 24 inbred F344 rats by sc injection of N-methyl-N-benzylnitrosamine at a dose level of 2.5 mg/kg weekly for 20 weeks. All of these rats also developed papillomas, 67% developed pedunculated papillary carcinomas, and 63% developed carcinomas that invaded the wall. Of 191 total neoplasms, 66% were papillomas, 17% were papillary carcinomas, and 17% were carcinomas that invaded the wall. The neoplasms were well differentiated with various degrees of keratinization. Anaplastic areas were found in most lesions, but were more common in carcinomas. Neoplasms that invaded the wall were sessile, with prominent intraluminal growth, or infiltrating, with predominant intramural growth. Penetration through the wall was observed, but neither metastases nor invasion of adjacent tissues was found. In addition to neoplasms, atypical endophytic proliferation of basal and spinous cells was observed in some of these rats. Proliferative or neoplastic changes were not observed outside the upper gastrointestinal tract.


Modulation of sensitivity to natural killer cell lysis after in vitro explantation of a mouse lymphoma.

On the basis of studies indicating that natural killer (NK) cells of the mouse can selectively kill certain syngenetic, allogeneic, and xenogeneic tumor cells in short-term Cr release assays and that cell lines established in vitro are more sensitive than the corresponding ascites tumor cells passaged in vivo, the kinetics of the modulation to increased sensitivity was studied after in vitro explanation of the A/Sn mouse-derived YAC ascites lymphoma. Sensitivity to NK lysis appeared after 3 weeks of culturing and reached the level of the continuously cultured line after 2 months. With the more sensitive competition assay, a change could be demonstrated as early as 2--24 hours of culture. The expression of the Moloney murine leukemia virus-determined, cell-surface antigen, measured by quantitative absorption with intact cells, increased in parallel with the NK sensitivity. In contrast, the H-2 alloantigen concentration decreased during in vitro culture.


Selection and biologic properties of malignant variants of a murine lymphosarcoma.

A syngeneic tumor model system with the RAW117 lymphosarcoma cell line was developed for use in investigations of host and tumor cell properties associated with an enhanced state of malignancy. This BALB/c mouse model was found to be similar to human lymphosarcoma in that liver and spleen were the major organs involved. Sequential in vivo selections were performed by iv tumor cell inoculation, removal of resulting solid liver tumor nodules for growth in vitro, and reinjection of the cultured cells iv. After ten such sequential selections for implantation, invasion, survival, and growth in liver, a lymphosarcoma cell line was obtained (RAW 117-H10) that formed approximately 200-fold more gross liver tumor nodules than did the parental tumor cell line in comparative biologic assays and displayed enhanced malignant properties when monitored by time of host death. Very few lung nodules or tumors were present at other sites with either the parental or any of the selected RAW117 lines, which confirms previous reports in which in vivo sequential selection yielded stable cell lines with preferential tumor colonization at specific sites.


Rat differences in mammary tumor induction with estrogen and neutron radiation.

Young adult female rats of either the Sprague-Dawley stock or the ACI strain were each given an implant of a compressed pellet of 5 mg diethylstilbestrol (DES) and 15 mg cholestrol 2 days before irradiation with 0.4, 1.3, or 4.0 rads of 0.43-MeV neutrons. These rats were studied, along with appropriate irradiated and nonirradiated controls, until death or for a maximum of 48 weeks. Response differences between the strain and stock included the following: DES produced both pituitary tumors and mammary adenocarcinomas (MAC) in ACI rats only. Neutron radiation increased mammary fibroadenoma (MFA) formation  in Srague-Dawley rats only. No interactions between DES and radiation on MAC formation in Sprague-Dawley rats or MFA formation in ACI rats were demonstrated. However, when DES and neutron radiation were combined, DES appeared to inhibit the MFA response to radiation in Sprague-Dawley rats. In contrast, DES appeared to act synergistically with neutron radiation on MAC formation in ACI rats. These results clearly demonstrate rat differences in mammary gland carcinogenesis in response to estrogen, to radiation, or to a combination of both agents.


Resistance and cross-resistance of cultured leukemia P388 cells to vincristine, adriamycin, adriamycin analogs, and actinomycin D.

Cultured P388 cells derived from leukemia P388 passaged in vivo in (C57BL X DBA/2)F1 mice were approximately one-tenth less sensitive to N-trifluoroacetyladriamycin-14-valerate (AD32) and cinerubin A, inasmuch as the concentrations of these agents had to be increased tenfold to produce a reduction in cell viability of the same order of magnitude as that produced by adriamycin, daunomycin, or actinomycin D. Cultured P388 cells derived from resistant cell populations developed in vivo retained their resistance to vincristine. These resistant cells exhibited cross-resistance to actinomycin D, adriamycin, daunomycin, and AD32, but cross-resistance to cinerubin A could not be detected. Data also showed that the vincristine-resistant cells were more sensitive to AD32 (2.8 x 10(-6) M) than to adriamycin (3.4 x 10(-6) M) during a 6-hour exposure of cells to agents.


Propionibacterium acnes-mediated humoral immune responses to tumor-specific antigens on rat liver cells transformed in vitro by chemical carcinogens.

Effects of Propionibacterium acnes on production of antibodies against tumor-specific membrane antigens were investigated in syngeneic inbred BD IV and BD VI rats. BD rat liver cell lines transformed in vitro by chemical carcinogens were used as target cells for tumor-specific antigens. By membrane immunofluorescence, antibodies against these rat liver cell lines were detected in syngeneic BD rat sera. Antibodies were produced in syngeneic rats under the adjuvant effect of heat-killed P. acnes only. In assays with various target cells and absorption experiments, the antibodies reacted with a tumor-specific individual antigen or tumor-specific cross-reacting antigen on the surfaces of transformed BD rat liver cells. No antibodies against these antigens were found in the sera obtained from syngeneic rats immunized with either the transformed cell lines or P. acnes but not with both. Freund's complete adjuvant did not induce antibodies against these tumor-specific antigens.


Spontaneous hepatomas in mice inbred from Ha:ICR Swiss stock: effects of sex, cedar shavings in bedding, and immunization with fetal liver or hepatoma cells.

Mice from Ha:ICR noninbred Swiss stock were mated brother X sister for 21--25 generations and then maintained up to the age of 33 months. Hepatomas developed in 62.8% of 86 males autopsied at 349--999 days of age (mean age = 21.1 mo). Of 130 females, 6.9% had hepatomas when autopsied at 328-825 days of age (mean age = 18.7 mo). Hepatoma incidence in males at 18 months of age was not affected by the presence or absence of cedar shavings in the bedding or by immunization of 3-month-old males with 2 weekly inoculations of 150 microgram (protein) sonicate of fetal liver or spontaneous hepatoma cells.


Tumor growth inhibition and potentiation of immunotherapy by indomethacin in mice.

Indomethacin was continuously administered in the drinking water of inbred C3H mice given grafts of syngeneic 3-methylcholanthrene-induced fibrosarcomas. A minor proportion of these animals died at the same time as the untreated controls, and others completely rejected their tumors; however, in most cases, the tumor growth rate was significantly slowed, and growth recommenced rapidly after drug withdrawal. This was the pattern for tumors either in their 10th to 14th transplant generation or only their third in vivo passage. Indomethacin exerted little prophylactic effect, in that it neither increased the minimal cell number required to initiate tumor growth nor significantly decreased the proportion of tumors established in drug-treated animals recieving tumor grafts. The injection of killed Corynebacterium parvum organisms into small, growing McC3-I tumors [intratumor (IT) route] caused the regression of most of these. In contrast, IT injection of BCG, ip injection of C. parvum, or IT injection of C. parvum into larger tumors had no effect. Oral administration of indomethacin enhanced BCG treatment and augmented the activity of C. parvum injected either systemically into animals with small tumors or IT into those with substantial tumor burdens. The duration of these effects was, however, often dependent on the continued administration of the drug.


Increase in cancer of the corpus uteri in the San Francisco-Oakland standard metropolitan statistical area, 1960--75.

A significant rise in the incidence of carcinoma of the corpus uteri in women of the San Francisco-Oakland standard metropolitan statistical area (SMSA) was reported by the Resource for Cancer Epidemiology. The incidence among white females increased by over 50% in the 6 years between 1969 and 1975. The increase was limited to the groups over 50 years old and to invasive cancers of the endometrial lining. The increase occurred in all five of the SMSA counties and, in white women in Aalmeda County, the average annual incidence for the 50- to 74-year age group tripled in 15 years. The rise was greatest in the areas of most affluence. Possible spurious causes of increase, such as changing diagnostic criteria, better case finding, or better reporting were examined and ruled out. The data suggested that the increase was due to the recent introduction of a potent endometrial carcinogen to the population group affected.


Sensitization in vitro to murine myeloblastic leukemia cells by xenogeneic immune RNA.

Normal murine spleen cells were sensitized to syngeneic myeloid leukemia cells by RNA extracted from the lymph nodes and spleens of Hartley guinea pigs immunized with the murine leukemia cells. Sensitization mediated by RNA was an active process that required physiologic temperature and at least a 10-minute incubation. RNA extracted from unimmunized guinea pigs of guinea pigs immunized with normal spleen cells failed to sensitize the mouse spleen cells. Sensitization was specifically directed toward leukemia cells, whereas the spleen cells remained unreactive toward normal spleen or bone marrow cells. The sensitizing moiety was RNA itself inasmuch as it was inactivated by RNase and not by DNase or pronase. Preparations whose RNA patterns on sucrose density centrifugation gave evidence of degradation of the RNA did not sensitize normal spleen cells. These studies demonstrate that xenogeneic immune RNA can specifically sensitize normal spleen cells to syngeneic myeloid leukemia cells.


Aplastic carcinoma in diabetic mice: hyperglycemia-suppressed proliferation rate and insulin synthesis by tumor cells.

Increased glucose levels in blood of diabetic and of normoinsulinemic hyperglycemic CBA/H mice were accompanied by suppressed growth of aplastic carcinoma. Tumors maintained in diabetic mice grew faster after each subsequent transplantation into diabetic mice, but those maintained in hyperglycemic normoinsulinemic mice grew at a constant rate. Evidence revealed that tumor growth was suppressed by hyperglycemia. The observed proliferation enhancement of aplastic carcinoma maintained in diabetic mice was caused by de novo insulin synthesis, probably by the tumor cells themselves.


Redistribution and modulation of Gross murine leukemia virus antigens induced by specific antibodies.

Gross murine leukemia virus (G-MuLV)-induced rat leukemia cells in tissue culture replicate G-MuLV, express strong virus-associated membrane antigenicity, and are consistently killed by specific antibodies and complement in cytotoxicity tests. To explore the effect of specific antibodies, rat anti-G-MuLV antisera were added to the cultures of leukemia cells for variable periods of time. Redistribution of virus particles as well as of membrane virus antigens in the form of polar patches and caps was observed by electron microscopy, indirect immunofluorescence, and immunoelectron microscopy. Substantial decreases in cytotoxicity indexes accompanied these changes. The antigen modulation induced by anti-G-MuLV antibodies in vitro paralleled similar changes obtained in vivo by transplanttion of leukemia cells in rats with high anti-G-MuLV antibody titers. The importance of antigen modulation in this system resides in its direct relationship with the malignant potential of the leukemia cells.


Selective effects of two chloromethyl ketones on amino acid and phosphate uptake in rat liver and tumors.

Injection of L-1-tosylamido-2-phenylethyl chloromethyl ketone (TPCK) at a level of 10 mg/100 g body weight inhibited the incorporation of 3H-labeled amino acids into protein in Morris hepatomas 7777and 9618A2. The degree of inhibition was similar in cytoplasmic proteins and in histone and nonhistone nuclear protein fractions. There was no inhibitory effect on 3H-labeled amino acid incorporation in the livers of the tumor-bearing rats. The inhibitory effect of N-tosyl-L-lysine chloromethyl ketone (TLCK) on incorporation of 3H-labeled amino acids was observed in both the slowly growing hepatoma 7787 and the rapidly growing hepatoma 7777. In hepatoma 7777, TLCK (2.5 mg/100 g body wt) exerted a greater inhibitory effect on incorporation when administered 60 minutes before [3H]leucine injection than when injected simultaneously. Studies on tissue uptake of amino acids, thymidine, and phosphate indicated that inhibitory effects of TPCK and TLCK on active transport may be a major factor in the action of these drugs on macromolecular synthesis. The inhibitory effects of TPCK and TLCK seen in transplanted hepatomas and a colon tumor were not generally seen in normal tissues of the tumor-bearing rats.


Analysis of human cancer DNA for DNA sequences of human adenovirus type 4.

We investigated whether human adenovirus type 4 (Ad4) might cause cancer in humans. Cell culture and animal model studies indicated that Ad4-induced human tumors should contain Ad4 DNA sequences. Thus Ad4 DNA was labeled in vitro (sp act, approximately 10(7) 3H counts/min/microgram) and hybridized in liquid phase with DNA extracted from human tumors. No viral sequences were detected in 31 squamous cell carcinomas of the lung, 5 adenocarcinomas of the lung, 4 oat cell carcinomas of the lung, 4 carcinomas of the stomach, 10 carcinomas of the colon, 3 carcinomas of the kidney, 3 carcinomas of the breast, 2 carcinomas of the ovary, and 6 Hodgkin's lymphomas. Reconstruction experiments with added Ad4 DNA indicated that the probe detected about 1 copy of 5% of the Ad4 genome per tumor cell. Therefore, these data were strong evidence (but did not prove) that none of these particular tumors were induced by Ad4.


Ultrastructural concomitants of sodium butyrate-enhanced ectopic production of chorionic gonadotropin and its alpha subunit human bronchogenic carcinoma (ChaGo) cells.

Sodium butyrate treatment of cultures of ChaGo (human lung cancer) cells resulted in increased production of human chorionic gonadotropin (hCG) and its alpha subunit (hCG-alpha) and induced a variety of morphologic changes. Elongation and flattening of cells were seen by light microscopy. Immunocytochemistry with antisera against hCG and against hCG-alpha showed an increase in cells containing stainable hCG-alpha. Scanning electron microscopy demonstrated enhanced adhesion of cells to glass cover slips, with elongation, flattening, and decreased cytoplasmic blebs. Ultrastructural changes were examined by transmission electron microscopy and evaluated quantitatively by an unbiased observer. Significant findings included increases in perinuclear tonofilaments, smooth endoplasmic reticulum vesicles, dense mitochondrial inclusions, and lipid granules, as well as decreases in intercellular desmosomes, free polyribosomes, mitochondrial dense granules, and Golgi complexes. The most notable change, a marked decrease in condensed chromatin clumps, may have reflected a butyrate-induced biochemical modification of chromatin leading to enhanced accessibility of certain genes for transcription.


Control of solid tumor metastases with a high-molecular-weight derivative of methotrexate.

Methotrexate (MTX) covalently bound to bovine serum albumin (MTX-BSA), injected ip (10 mg/kg) once every 4 days for a total of 4 doses, was more effective than an equivalent dose of free MTX in reducing the number of metastases observed in female (C57BL/6 X DBA/2)F1 mice bearing the sc implanted Lewis lung carcinoma. Treatment with the high-molecular-weight derivative of MTX in addition caused a decreased rate of growth of the primary tumor and a modest increase in the life-span of the tumor-bearing animal. When tumor-bearing mice were killed after receiving injections of [3H]MTX or [3H]MTX-BSA, no difference in the amount of drug was found at the tumor site after 1 hour; however, after 8 or 24 hours, twice as much radioactivity was found in the tumors of mice treated with carrier-bound drug. Analysis of this radioactivity indicated a ratio of 60--80% carrier-bound to 20--40% free MTX.


Influence of inoculation site on development of the Lewis lung carcinoma and suppressor cell activity in syngeneic mice.

The growth of the Lewis lung carcinoma (3LL) was studied in syngeneic C57BL/6 mice inoculated sc with similar numbers of tumor cells in either the flank or the hind footpad (fp). After injection of small numbers of 3LL cells, the incidence of tumors was lower in the flank than in the fp. However, after a successful 3LL transplant, tumors in the flank progressed faster than those in the fp, as evidenced by the early metastatic dissemination to the lungs and the shorter survival of the hosts. Local adoptive transfer tests demonstrated the early appearance of suppressor cell activity in spleens from mice bearing tumors in the flank. Adult thymectomy as well as treatement with antithymocyte serum after the tumor transplant inhibited the growth of a flank tumor but did not modify significantly that of an fp tumor. Thus variations in the site of a subcutaneous tumor implant resulted in differences in tumor development that appeared to depend on the characteristics of the immune response elicited by the inoculum.


Acute promyelocytic leukemia presenting as a pelvic mass.

The case history of a child with acute promyelocytic leukemia (APL) is reported to illustrate both an unusual presentation of APL as a pelvic mass and to review the pathophysiology and treatment of the disease. Therapy of APL consists of chemotherapy, namely adriamycin/daunomycin for remission induction, and of control of disseminated intravascular coagulation. A chloroma, if present, may require local irradiation in addition to chemotherapy. With aggressive management, the number of prolonged remissions may be greater for APL than for any other form of acute myelogenous leukemia (AML), with significant numbers of patients achieving five-year survival.


L-Asparaginase-induced coagulopathy during therapy of acute lymphocytic leukemia.

L-Asparaginase-induced coagulation abnormalities were observed in all patients receivng this drug. All patients studied demonstrated low factor IX and fibrinogen levels and most (75%) had low levels of factor XI. Disturbances in other factors were much less frequent. Despite the presence of markedly abnormal coagulation studies, clinical bleeding was not observed.


Remission induction in acute myelogenous leukemia using cytosine arabinoside synchronization: a Southwest Oncology Group Study.

The use of cytosine arabinoside (Ara-C) infused at kinetically suggested intervals is reported in 40 pediatric patients with acute myelogenous leukemia (AML) and its subtypes. Response was observed in 17 of the 34 evaluable patients. However, the severe, often fatal effects of the regimen prevent its recommendation as a standard induction regimen in AML in children.


High cervical percutaneous cordotomy in intractable pain.

The authors report on 200 cervical percutaneous cordotomies in 146 patients who were suffering from intractable pain. In order to assess the success rate and the incidence of relapse, the neurological findings immediately post-operatively were compared with the results of a later follow-up. The prospect of success in the treatment of pain appears to depend on the anatomical representation in the spino-thalamic tract of the region of the body which is involved. The incidence of complications and the mortality are compared with the observations of other authors and with the results of open cordotomy.


Treatment in an alcoholism and drug addiction unit.

Estimates of the number of alcoholics in New Zealand indicate that a highly selected minority actually receive treatment for their alcoholism. This report examines who refers these patients to an alcoholism and drug dependence unit, the utilisation of compulsory treatment, and the demographic and social characteristics of the patients. A one year sample of these patients was followed for 12 months to assess treatment outcome. One year after discharge 11 percent had adopted an abstinent life-style. Forty-two percent had been rehospitalised.


Liver biopsy--an outpatient procedure.

Experience with 67 liver biopsies performed on outpatients has been retrospectively analysed. One serious complication was encountered but would not have been detected earlier even had the patient been retained in hospital for 48 hours. The results suggest that liver biopsy can be performed on many outpatients with safety.


Eye injuries produced by vehicle safety glass.

The eye injuries resulting from motor vehicle accidents over the three years, 1975 to 1977 inclusive are considered. A high incidence of severe eye injury produced by safety windscreen glass continues. The results of this survey are compared with a survey of the period 1970 to 1974 inclusive.


Perinatal events in the Dunedin City population 1967-1973.

The incidence of an array of maternal, obstetric and neonatal events occurring in the Dunedin City population in the six years from 1 August 1967 is presented. This population was not truly representative of the total New Zealand population. The total births in Dunedin City were 10,091 and the perinatal mortality was 17.5 per 1000 total births. Some of the pertinent findings were: 8.8 percent of the mothers were either not married or were not living with their husbands; 36.5 percent were primigravida; 13.2 percent of mothers were less than 20 years of age; 9.6 percent of mothers had an adverse past obstetric history; 11.5 percent had a diastolic blood pressure in excess of 90mmHg during the pregnancy; 5.0 percent had an antepartum haemorrhage of which 45.4 percent occurred in the first trimester; 6.5 percent of newborns were non-European; 2.0 percent were multiple births; 0.8 percent had a single umbilical artery; in 27.4 percent the delivery was not spontaneous; 6.2 percent had a low birth weight; 4.0 percent were born preterm; 5.2 percent of newborns experience neonatal complications; 2.1 percent had a major, and 6.4 percent a minor congenital fault.


Breast feeding and some reasons for electing to wean the infant: a report from the Dunedin Multidisciplinary Child Development Study.

Data are presented on the prevalence of breast feeding among 1037 Dunedin mothers who gave birth to infants between April 1972 and March 1973 and their reasons for weaning. Although breast feeding was becoming more common at that time, more than two-thirds of the mothers weaned their babies as a result of the difficulties they encountered. One of the most significant factors in lactation failure is the mismanagement of breast feeding by health professionals.


Detection of hearing loss in infancy.

A neonatal hearing screening programme and a nine-month at risk hearing screening programme are analysed. Neither contributed significantly to the detection of deaf infants though nine month at risk screening can be worthwhile if well administered. Age of detection data for deaf pre-schoolers in New Zealand are presented. The responsibility of all professionals in contact with the infant population for early detection and referral of deaf infants is stressed.


The diagnosis of incomplete abortion.

A prospective study of 203 patients referred with a diagnosis of incomplete abortion is reported and the final histological diagnosis is discussed. Eighty-six patients (42 percent) were not pregnant, and 14 (7 percent) had other abnormalities of pregnancy. Clinical features of value in confirming the diagnosis were cervical dilation (misleading in 6 percent), uterine enlargement (misleading in 31 percent) and pain (misleading in 34 percent). Amenorrhoea was significantly shorter in patients with dysfunctional bleeding and bleeding prolonged in the other groups, but a wide range was noted. Age did not differ significantly between the two groups. A histological diagnosis was made in all but five patients. No clinical feature was completely reliable and curettage was often necessary to reach a final diagnosis.


The prevalence of disturbance of cardiac rhythm in healthy New Zealand Adults: a pilot study.

Continuous portable 24-hour tape recorded monitoring of the electrocardiogram in 189 healthy adults was used to provide data about dysrhythmia during normal daily activity. The age of the subjects ranged from 20 to 70 years and the mean age was 44. One hundred and forty-eight were less than 50 years of age. Dysrhythmia, mainly asymptomatic, occurred in 71 subjects (37 percent). In 31 (16 percent) it was ventricular, in 20 (10.5 percent) it was supraventricular and in a further 20 (10.5 percent) it was combined. In 12 (6.3 percent) ventricular ectopy was considered potentially serious. It was not more prevalent in smokers. This study shows a lesser number of normal subjects with dysrhythmia than in most other reported studies.


Cardiac rupture: 30 consecutive cases from a series of medicolegal autopsies.

Factors underlying spontaneous cardiac rupture were studied in a consecutive series of 30 hearts with ruptured infarcts removed at medicolegal autopsy. Normal and diseased heart muscle and narrowed coronary arteries were examined microscopically. The average age of the 15 women at death was 80 years, and of the 15 men, 73 years. All of the ruptures occurred through a recent transmural left ventricular myocardial infarction which was associated with coronary arteries severely narrowed by atherosclerosis. Nine (33 percent) of the cases showed an occlusive coronary thrombosis. Many of the subjects had no symptoms of recent myocardial ischaemia.


Indomethacin-associated peptic ulceration.

A review has been made of the hospital case notes of 32 patients with indomethacin-associated peptic ulceration seen over a four year period in Dunedin. Ulceration attributed to indomethacin therapy was found to particularly involve elderly women, in contrast to a predominance of males and a younger mean age at diagnosis in non-drug associated ulceration seen over the same period. The indomethacin-associated ulcer patients were more frequently complicated by haematemesis or melaena (two-thirds of cases compared to one-quarter for the group not on drugs) and relative hypochlorhydria was frequently noted at the time of gastroscopy in this group as compared to the other cases. It is suggested that patients warranting prolonged treatment with indomethacin require regular reassessment for any evidence of dyspepsia or anaemia, and that barium meal or gastroscopy are indicated for the presence of even mild abnormality of these types.


Vertebral artery occlusion following manipulation of the neck.

A 23-year-old woman developed brainstem infarction following cervical manipulation. Vertebral angiography showed total occlusion of the left vertebral artery with a thrombus extending into the basilar artery. The literature dealing with this rare but serious complication of cervical manipulation is reviewed.


Near-drowning in an infant: case report.

A case is presented of an infant who may have been immersed in water for 15 minutes, presenting apparently dead by instant assessment criteria, who was resuscitated and rehabilitated to make an excellent recovery.


Capgras syndrome: two case reports.

Two cases of Capgras syndrome are reported. They constitute further evidence that Capgras syndrome is a delusion which could occur in any psychotic state, rather than a syndrome with specific organic pathology.


Hematologic emergencies in children.

Hematologic emergencies may be defined as sudden or unexpected life-threatening events in clinical hematology and oncology which require immediate action predominantly based on clinical judgements and supported only by investigations that can be expected to produce results rapidly. It is convenient to classify these emergencies according to disorders affecting the erythrocytes; leukocytes; platelets; hemostasis; defence mechanisms against infection; the respiratory system; and emergencies related to drugs used for the treatment of neoplasia. A proposed classification is outlined. Part of treatment of hematologic emergencies is to ensure that the cicumstances which caused them will not recur in the same patient or those with similar disorders.


Chronic myelocytic leukemia terminating in blast cell crisis with lymphoblastic characteristics.

A child with chronic myelocytic leukemia (CML), Philadelphia chromosome positive, developed a non-T cell, non-B cell, acute lymphocytic leukemia (ALL) during her blast cell crisis. The diagnosis was suggested by light microscopy and supported by histochemical stains and transmission electron microscopy. Immunologic studies showed the presence of a non-T, non-B leukemic blast population--indistinguishable from the most common form of ALL (null cell type). Markedly elevated terminal deoxynucleotidyl transferase (TdT) activity was found. The findings support the hypothesis that the primary cell involved in CML is a stem cell with pluripotential characteristics; frequently the blast cell proliferative phase terminates in acute myeloblastic leukemia, but it may also terminate in ALL. The TdT activity may be evidence of leukemic transformation and not necessarily related to the thymic origin of the lymphocytes.


On the agalactia post partum in the sow. A clinical study.

The purpose of the present investigation was to study the clinical symptoms of agalactic sows post partum in randomly selected swine herds. The study comprised 71 sows affected with agalactia post partum and 71 healthy sows from the same herds used as controls. Average morbidity of the disease in these 50 herds, consisting of an average of 25 sows, was 12.8%. Sixty-three per cent of the agalactic sows were affected within one day after farrowing. There was no difference in gestation length between healthy sows and agalactic sows. The body temperature was significantly higher for affected than for healthy sows. Mastitis was diagnosed in 35 out of 71 agalactic sows. The criteria for mastitis were swelling and herdening of one or several udder glands. Vaginal discharge was recorded for affected sows (55/57) as well as for healthy sows (51/58) and is therefore not significantly associated with agalactia. The temperament of the agalactic sows was moderately or severely affected in 62 out of 71 agalactic sows. Constipation was recorded for 13/59 agalactic sows and for 3/57 normal sows. The agalactic sows had significantly higher number of piglets per litter at birth while the litter size was higher for healthy sows at weaning. Numerically, more sows were culled among agalactic sows (16/48) than among normal sows (6/42). Moreover, sows affected with agalactia at the previous parturition were more inclined to meet with the disease at the next parturition. Further studies comprising large groups of animals are, however, necessary for evaluation of this question.


Spiculated periosteal reaction in metastatic disease resembling osteosarcoma.

Sixteen cases of metastatic bone deposits presenting with sunburst spiculated periosteal reaction are presented. The most common origin was from prostatic carcinoma followed by neuroblastoma. A moderate soft tissue mass component was seen in 70% of the cases. The possible pathophysiologic reasons for this type of periosteal reaction are presented. The differential diagnosis is outlined.


[Compressive strength and deformation of dental cements].

Several dental cements have been tested for compressive strength, modulus of elasticity and plastic strain at fracture. Sylindrical specimens (4 x 6 mm) were compressed to fracture with two different crosshead speeds (2 mm/min, 0.1 mm/min) at two temperatures (23 +/- 1 degrees C and 37 +/- 1 degrees C). The results showed that the zinc phosphate cement had relatively high strength and a very small elastic and plastic strain during compression. The luting type of glass-ionomer cements showed properties near to that of the zinc phosphate cement. The other cements had either lower strength or higher elastic and plastic deformation than the zinc phosphate cement. Several cements showed a marked reduction of the mechanical properties when tested at a low crosshead speed or at 37 degrees C.


Energetics of enzyme catalysis.

Quantitative studies of the energetics of enzymatic reactions and the corresponding reactions in aqueous solutions indicate that charge stabilization is the most important energy contribution in enzyme catalysis. Low electrostatic stabilization in aqueous solutions is shown to be consistent with surprisingly large electrostatic stabilization effects in active sites of enzymes. This is established quantitatively by comparing the relative stabilization of the transition states of the reaction of lysozyme and the corresponding reaction is aqueous solution.


Spectroscopic studies of oxy- and carbonmonoxyhemoglobin after pulsed optical excitation.

The photolysis of HbO2 and HbCO has been investigated with picosecond laser techniques. Transient absorption spectra were measured in the Soret and visible regions after excitation with 353- or 530-nm pulses. The photoproducts appeared within 8 psec and exhibited considerably broadened deoxyhemoglobin-like spectra, which persisted to 680 psec. The altered spectra are attributed to the production of deoxyheme conformational and spin states that might result from the intense excitation.


Interacting enzyme systems at steady state: further Monte Carlo calculations on two-state molecules.

In this work, Monte Carlo calculations were made on a 10 x 10 lattice of two-state, steady-state enzyme molecules in two special cases for which the Bragg-Williams (mean field) approximation had earlier produced some very interesting phase-transition properties. The Monte Carlo results proved to be similar to Bragg-Williams in some respects but not in others. The discrepancies are attributed primarily to; (i) inadequate treatment by Bragg-Williams of strong negative cooperativity; and (ii) the finite size of the 10 x 10 lattice used in the exact calculations.


Cluster characterization in iron-sulfur proteins by magnetic circular dichroism.

We report magnetic circular dichroism (MCD) spectra of 4-Fe iron-sulfur clusters in the iron-sulfur proteins Chromatium high-potential iron protein  (HIPIP), Bacillus stearothermophilus ferredoxin and Clostridium pasteurianum ferredoxin. The MCD is found to vary significantly with cluster oxidation state but is relatively insensitive to the nature of the protein. The spectra obtained are compared with the corresponding spectra of iron-sulfur proteins containing 2-Fe clusters. It is concluded that MCD is useful for the characterization of iron-sulfur cluster type and oxidation state in iron-sulfur proteins and is superior for this purpose to absorption and natural circular dichroism spectroscopy.


Filter-binding assay for covalent DNA-protein complexes: adenovirus DNA-terminal protein complex.

A rapid, simple, and quantitative filter-binding assay using glass fiber filters has been developed to detect the convalent adenovirus DNA-terminal protein complex. The assay is unusually sensitive because binding of protein-free DNA generally is less than 0.1%. Binding of the adenovirus complex to filters is mediated by terminal protein. We have found that: (i) the adenovirus complex binds maximally to filters in NaCl at concentrations higher than 0.2 M; (ii) noncovalent complexes between protein-free DNA and adenovirus proteins bind to filters in salt at concentrations lower than 0.4 M but not in concentrations higher than 0.7 M; and (iii) protein-free DNA alone binds to filters in guanidine.hydrochloride at concentrations higher than 0.8 M. By varying the ionic conditions, "all or none" modulation of these interactions can be achieved.


Effect of thyroid phospholipids on the interaction of thyrotropin with thyroid membranes.

Various lipids extracted from bovine thyroid glands were tested for their ability to affect the binding of 125I-labeled thyrotropin to bovine thyroid membranes. The most potent inhibitors were the acidic phospholipids in the order cardiolipin greater than phosphatidylglycerol greater than phosphatidylinositol greater than phosphatidylserine. Other phospholipids, neutral lipids, and neutral glycolipids were ineffective. As reported previously [mullin, B. R., Pacuszka, T., Lee, G., Kohn, L. D., Brady, R. O. & Fishman, P. H. (1978) Science 199, 77--79], thyroid gangliosides also inhibited thyrotropin binding but not as effectively as phospholipids. In addition, the mode of action of these two classes of acidic lipids was different. When thyroid membranes were preincubated with the phospholipids and then separated by centrifugation, their ability to bind thyrotropin was still diminished. In contrast, gangliosides appear to interact with the hormone and not with the membranes. The effect of phospholipids on thyroid membranes was further examined by incubating the membranes with phospholipase A. The treated membranes now bound more labeled hormone. These results suggest that certain acidic phospholipids, which are present in only small amounts in thyroid membranes, influence the state of the thyrotropin receptor and its ability to bind thyrotropin.


Chimeric toxins: toxic, disulfide-linked conjugate of concanavalin A with fragment A from diphtheria toxin.

A disulfide-linked conjugate of concanavalin A (Con A) and fragment A from diphtheria toxin has been synthesized and shown to be toxic for HeLa (human), Chinese hamster ovary (CHO), and SV3T3 (murine) cells. The conjugate was constructed by first coupling cystamine to Con A with a carbodiimide reagent and then reacting the modified Con A with reduced fragment A under conditions promoting disulfide interchange. The desired conjugate, obtained in nearly 50% yield relative to input of fragment A, was purified by affinity chromatography on Sephacryl S-200 and NAD-Sepharose; on analysis, it gave an average of 1.4 molecules of fragment A per tetrameric Con A molecule. The conjugate proved to be about equally active in inhibiting protein synthesis in HeLa, CHO, or SV3T3 cells in culture but was inactive relative to controls in a toxin-resistant strain of CHO cells containing altered elongation factor 2, the target protein of fragment A. With toxin-sensitive strains the conjugate was 100- to 1000-fold more active than controls, including fragment A, cystaminyl-Con A, and mixtures thereof, but was 1/50th to 1/500th as toxic as diphtheria toxin itself. Similar activity relative to controls was observed after intradermal inoculations in rabbits, and intravenous injections of the conjugate were lethal for mice. The activity of the conjugate in tissue culture was inhibited by Con A or alpha-methylmannoside but not by galactose. This and similar conjugates should be useful in studying mechanisms of entry of biologically active proteins into cells.


RNA sequencing with radioactive chain-terminating ribonucleotides.

A rapid method for determining nucleotide sequences in RNA is described. It employs the 3'-deoxy analogues of the ribonucleoside triphosphates as specific chain terminators during RNA synthesis. For example, the inclusion of 3'-deoxyuridine 5'-triphosphate in an RNA synthesis reaction in addition to the four usual ribonucleoside triphosphate precursors results in the synthesis of a set of different-length product strands that terminate in a 3'-deoxyuridine that has been incorporated in place of uridine. To sequence an RNA, four separate reactions are run, each employing a different 3'-deoxy terminator. Parallel electrophoretic analysis of the resulting four sets of specifically terminated product chains leads to a direct reading of the nucleotide sequence. We tested this method by sequencing MDV-1 (-) RNA, a molecule that is synthesized in vitro by phage Qbeta replicase. The sequence read from the resulting gels agreed completely with the known sequence of MDV-1 (-) RNA. The bands in some regions of the sequencing gels were unusually close to one another, as has also been observed in other rapid sequencing procedures, making order assignment in these regions very difficult. Because the secondary structure of MDV-1 (-) RNA was known, it was shown that the compression of the bands is due to the persistence of secondary structures during electrophoresis. Thus, structured regions of nucleic acids may introduce difficulties for sequencing techniques that employ the currently available methods of gel electrophoresis.


In vitro RNA-RNA splicing in adenovirus 2 mRNA formation.

"Splicing" of the precursor to an adenovirus mRNA was accomplished in isolated cell-free extracts. Nuclei were prepared from hypotonically swollen cells that had been labeled with [3H]uridine for 10 min prior to nuclear isolation. Addition of a "cytoplasmic" fraction was required for the splicing to occur. The nuclear precursor, a poly(A)-terminated RNA molecule approximately 5 kilobases long, contained sequences complementary to the 58.5--75.9 region of the adenovirus 2 genome, including those sequences spliced out of the mature mRNA molecule. The in vitro spliced product was a poly(A)-terminated RNA molecule identical in size to the cytoplasmic 72,000 Mr protein mRNA (2 kilobases long) in which the sequences encoded in the 70.7--75.9 region of the viral genome were spliced to those encoded at 58.7--65.6, with the sequences encoded at 66.1--70.7 deleted.


Tumorigenicity of the optical enantiomers of the diastereomeric benzo[a]pyrene 7,8-diol-9,10-epoxides in newborn mice: exceptional activity of (+)-7beta,8alpha-dihydroxy-9alpha,10alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene.

The tumorigenicities of benzo[a]pyrene and each optical enantiomer of the diastereomeric benzo[a]pyrene 7,8-diol-9,10-epoxides derived from trans-7,8-dihydroxy-7,8-dihydrobenzol[a]pyrene were tested by sequential intraperitoneal injection of mice with 1,2, and 4 nmol, or with 2, 4, and 8 nmol of each compound on the 1st, 8th, and 15th day of life, respectively. The experiment was terminated when the animals were 34--37 weeks old. (+)-7beta, 8alpha-dihydroxy-9alpha,10alpha-epoxy-7,8,9,10-tetrahydrobenzol[a]pyrene [(+)-BP-7beta,8alpha-diol-9alpha,10alpha-epoxide 2] had exceptional tumorigenicity, whereas benzo[a]-pyrene and the other three optically pure isomers of the benzo[a]pyrene 7,8-diol,9,10-epoxides had little or no activity. These results demonstrate differences in the carcinogenic activities of optically active isomers of a polycyclic hydrocarbon diol epoxide. Eleven percent of control mice had pulmonary tumors, whereas 71% and 100% of the mice treated with a total dose of 7 or 14 nmol of (+)-BP-7beta,8alpha-diol-9alpha,10alpha-epoxide 2, respectively, had pulmonary tumors. Control mice had an average of 0.12 pulmonary tumors per mouse, whereas mice treated with a total dose of 7 or 14 nmol of (+)-BP-7beta,8alpha-diol-9alpha,10alpha-epoxide 2 had 1.72 and 7.67 pulmonary tumors per mouse, respectively. Mice treated with 14 nmol of (-)-BP-7alpha,8beta-diol-9beta,10beta-epoxide 2, (-)-BP-7beta,8alpha-diol-9beta,10beta-epoxide 1, or (+)-BP-7alpha,8beta-diol-9alpha,10alpha-epoxide 1 had 0.13, 0.25, and 0.34 pulmonary tumors per animal, respectively.


Bomebesin: specific binding to rat brain membranes.

The binding of a radiolabeled bomebesin analogue to rat brain membranes was studied. [125I-Tyr4]Bombesin bound with high affinity (KD = 3 nM) to a single class of non-interacting sites. Binding was specific, saturable (3.8 pmol of sites/g of wet tissue), and reversible. Regional and subcellular distribution studies showed that the density of sites was 7-fold greater in the hippocampus than the medulla/pons and greater in synaptosomal fractions than in mitochondrial or nuclear fractions. The abilities of numerous bombesin analogues to induce hypothermia and to inhibit [125I-Tyr4]bombesin-binding activity correlate well. Numerous amino acid residues near the CONH2-terminal are required for high-affinity binding and biological potency.


Resolution of complex III of the mitochondrial electron transfer chain into two component complexes.

Complex III can be resolved into an electron transfer complex and an ion transfer complex. The electron transfer complex contains exclusively the oxidation-reduction proteins of complex III, and the ion transfer complex the capability for augmenting cation-induced fluorescence of 8-anilino-1-naphthalenesulfonic acid. This finding has important implications for the molecular mechanism of mitochondrial energy coupling.


Photodestruction of pheomelanin: role of oxygen.

Pheomelanin, the red-brown polymeric pigment in the skin and hair of red-headed humans, is composed of a protein fraction covalently bound to a colored chromophore. Photolysis of aerated aqueous phemelanin solutions, isolated from human red hair, results in destruction of the chromophore and liberation of the peptide fraction. The rate of photolysis depends on the pH and the concentration of both pigment and oxygen and is slightly inhibited by the enzyme superoxide dismutase (superoxide:superoxide oxidoreductase EC 1.15.1.1). Pheomelanin photolyzed in the presence of nitroblue tetrazolium results in the formation of a blue diformazan, whether or not oxygen is present. Superoxide dismutase inhibits the aerobic photoreduction of nitroblue tetrazolium whereas, in the absence of oxygen, no inhibition is observed. These experiments strongly suggest the involvement of superoxide in the aerobic photolysis of pheomelanin and point out a possible mechanism for ultraviolet-induced cell damage in redheads.


Activation energy for RNA transport from isolated rat liver nuclei.

The temperature dependence of ATP-enhanced RNA delivery from rat liver nuclei to a surrogate cytoplasm was investigated. Examination of linear-rate data on Arrhenius graphs of 1/T vs. log (% RNA delivered per min) revealed an activation energy of 12.5--13 kcal/mol. When data derived from longer incubation periods was displayed on Arrhenius graphs, we observed a discontinuous graph--two distinct linear segments with slopes of differing sign which intersected near 20 degrees C. It was demonstrated that this discontinuity was not due to lipid phase transition in the nuclear membranes and that its position depended upon treatment of the nuclei and upon additives to the incubation mixtures. The decline in transport apparent in the upper-temperature domain on 20-min Arrhenius graphs was shown to be based on the diffusion of transported macromolecular RNA back into the nucleus--a process greatly amplified by the rapidity of transport in this domain. The large net inward diffusion, in concert with significantly differing activation energies for RNA transport and passive diffusion, suggests that the process of nucleocytoplasmic RNA transport is not diffusion driven. Our data have established that an integral parameter of RNA transport (namely, the activation energy) remains unchanged in various in vitro manipulations.


Interactive computer surface graphics approach to study of the active site of bovine trypsin.

A descriptive medium for the presentation of protein structure has been developed and used to evaluate the structure of the active site of bovine trypsin (EC 3.4.21.4). This technique, involving advanced computer graphics technology, permits the facile display of a representation of the molecular surface of proteins of known structure and employs color to code the structural or chemical features of this surface. Benzamidine derivatives were inserted into the benzamidine-binding site of trypsin and the binary inhibitor-trypsin complex was evaluated by using the computer-generated structure. On the basis of qualitative assessments of the contribution of electrostatic and hydrophobic forces to the binding energy associated with complex formation, we made predictions concerning the effects of interaction of benzamidine substituents and amino acid side chains upon the binding energy associated with inhibitor-protein binding. The computer display of the molecular surfaces of the binary complex of substituted benzamidines and trypsin permitted unique insight into the identity and chemical properties of the atoms that participate at the interface of the molecular surfaces of the inhibitor and the protein. The computer-generated molecular surface display can potentially be combined with quantitative definition of the physical forces involved in the interaction of molecular surfaces. This technology should facilitate the study of the structure-activity relationship of substrates, inhibitors, and drugs that bind to proteins of known three-dimensional structure.


Vitamin K-dependent carboxylase: evidence for a hydroperoxide intermediate in the reaction.

Vitamin K is an essential cofactor for a microsomal carboxylase that converts glutamyl residues in endogenous precursor proteins to gamma-carboxyglutamyl residues in completed proteins. The same microsomal preparations convert vitamin K to its 2,3-epoxide, and it has been suggested that these two reactions (carboxylation and epoxidation) are coupled. Glutathione peroxidase, which reduces hydrogen peroxide and organic hydroperoxides, inhibits both of these reactions in a prepartion of microsomes solubilized by Triton X-100. Catalase has no effect. In the absence of vitamin K, and in the presence of NADPH, tert-butyl hydroperoxide acts as a weak vitamin K analog. At lower concentrations, tert-butyl hydroperoxide is an apparent competitive inhibitor of vitamin K for both the carboxylase and epoxidase reactions. These data are consistent with the hypothesis that both of these vitamin K-requiring reactions involve a common oxygenated intermediate, and that a hydroperoxide of the vitamin is the species involved.


Glucose binding and transport proteins extracted from fast-growing chicken fibroblasts.

Preconfluent or confluent fibroblasts grown in 5% serum medium yielded, without cell lysis, all the glucose-binding protein and most of the transport-stimulating activity in the cell wash fluid obtained with a 10 mM sodium octanoate-containing solution. For assay, octanoate was removed, and after the binding protein was labeled with [(14)C]glucose, the factors were chromatographed on Sephadex G-200 and the transport-stimulating and factor-bound [(14)C]glucose activities were measured. Three peaks were separated, which more or less overlapped for both functions; upon chromatography on DEAE-cellulose, these peaks yielded overlapping or separate peaks for the two functions, presumably indicating their separability. Serum, when similarly chromatographed, showed only peaks for transport which, with the exception of one major peak with both functions, more or less overlapped with those from the wash fluid. Glucose transport rates, when compared in fibroblasts grown in glucose and in fructose and in Rous sarcoma virus-transformed cells grown in glucose, were in the proportion of 1:3.7:6.3. Addition of extracted transport protein stimulated the transport of both the glucose-grown and fructose-grown normal cells but showed no effect on the transport of transformed cells. Addition of transport protein induced the formation of [(14)C]deoxyglucose 6-phosphate in amounts proportional to the increased transport of [(14)C]deoxyglucose into fibroblasts. On sodium dodecyl sulfate electrophoresis, using the tightly bound [(14)C]glucose for assay, purified binding protein yielded large fractions of 36,000 and 18,000 and small ones of 55,000 and 73,000 daltons; the 18,000-dalton fraction is supposedly the monomeric form of the binding protein.


Mammalian cell mutant requiring cholesterol and unsaturated fatty acid for growth.

A mutant requiring both cholesterol and oleate for growth has been isolated from mutagenized Chinese hamster ovary cells. By comparison with wild-type cells, sterol and unsaturated fatty acid biosynthetic activities in the mutant cells grown in fetal calf serum medium appear to be nearly intact. However, whole-cell radioactive acetate, mevalonate, dihydrolanosterol, and stearate incorporation studies show that sterol synthesis from acetate, lanosterol demethylation, and fatty acid desaturation are defective in the mutant cells grown in delipidated serum medium. In vitro enzyme assays with crude cell extracts demonstrated that beta-hydroxy-beta-methylglutaryl-coenzyme A reductase is not induced in the mutant. These experiments were substantiated by gas/liquid chromatographic analyses which showed the sterol content and the percentage unsaturated fatty acids in mutant cells to be drastically reduced when the cells are grown in delipidated serum medium. A spontaneous revertant exhibiting prototrophic growth in lipid-free medium has been isolated from 50 X 10(6) mutant cells. All three defects in this revertant reverted back in parallel, which suggests that these three biosynthetic activities may be controlled by a common regulatory mechanism.


Inhibition of growth of 3T3 cells by extract of surface membranes.

The growth of Swiss 3T3 cells can be inhibited by the addition of a plasma membrane enriched fraction from 3T3 cells [Whittenberger, B & Glaser, L. (1977) Proc. Natl. Acad. Sci. USA 74, 2251--2255]. We report conditions for the extraction of the inhibitory components from the membranes with octylglucoside. The solubilized components reversibly inhibit the rate of cell division of 3T3 but not of simian virus 40-transformed 3T3 cells. The inhibitory activity is heat labile and nondialyzable. The inhibition observed with the soluble extract can be reversed by mitogenic factors present in serum.


Structural origins of diamagnetic anisotropy in proteins.

Magnetic anisotropy in proteins and polypeptides can be attributed to the diamagnetic anisotropy of the planar peptide bonds. The alpha helix in particular has large anisotropy due to the axial alignment of the peptide bonds. The regular arrangements of the peptide bonds in beta pleated sheet and collagen structures also produce substantial anisotropy, but less than for alpha helix. The anisotropy permits orientation of small structures of these types in magnetic fields of several kilogauss.


Effect of transmembrane ion gradients on Raman spectra of sealed, hemoglobin-free erythrocyte membrane vesicles.

Sealed hemoglobin-free erythrocyte vesicles have been isolated. Imposition of transmembrane cation gradients increases the intensity of Raman scattering in the CH3-stretching region as observed with unsealed ghosts at temperatures greater than 38 degrees C and pH less than 7.0 [Verma, S. P. & Wallach, D. F. H. (1976) Proc. Natl. Acad. Sci. USA 73, 3358--3561]. Modifications in the amide I and amide III frequencies consistent with increased helicity of membrane proteins are observed upon imposition of a cation gradient. Spectrin-free vesicles also demonstrate cation gradient-sensitive intensity changes in the CH3-stretching region. However, no evidence for cation gradient-related protein conformation changes is found with these vesicles. The transmembrane potential of these vesicles has been altered by variations in anion composition and the electrogenic activity of Na+,K+-ATPase. The membrane potential was monitored by cyanine dye fluorescence. Imposition of a membrane potential (negative inside) also increased the intensity of Raman scattering in the CH3-stretching region. These results suggest that a transmembrane potential (negative inside) and/or cation gradient can energize membranes by compression of the apolar region and transfer of protein methyl residues into polar regions.


Conformational features of distamycin-DNA and netropsin-DNA complexes by Raman spectroscopy.

The binding of distamycin and netropsin to duplex DNA has been studied by Raman spectroscopy. Several changes occur in the Raman spectra of these drugs upon binding DNA. These changes were analyzed by assigning specific motions to the observed Raman bands through the use of molecular subunits of the drugs and normal mode calculations. Our analysis indicates that pyrrole ring and peptide group vibrations are altered upon binding to DNA. The environments of the pyrrole ring methyl groups are not affected by the binding. These data provide physical evidence consistent with a binding model in which the methyl groups on the pyrroles project away from the DNA and the peptide N-H groups form hydrogen bonds with the DNA.


Reciprocal effects in human hemoglobin: direct measurement of the dimer-tetramer association constant at partial oxygen saturation.

An equilibrium gel permeation technique has been developed for determining as a function of oxygenation state the equilibrium constants for association of hemoglobin subunits. By using this method, the dimer-tetramer constant for human hemoglobin at a partial oxygenation state corresponding to 20% saturation for tetramers has been determined as 3.7 X 10(6) M-1 (dimers). Under the same conditions the corresponding constant for fully oxygenated hemoglobin is 4.1 X 10(5) M-1. These results are found to be in good agreement with the predicted behavior of the association reaction based upon oxygen binding curves measured as a function of protein concentration. Thus a high degree of consistency is found between the two independent experimental approaches to the reciprocal effects of this linkage system, lending support to the theory proposed earlier for these phenomena.


Fibrinogen synthesis in serum-free hepatocyte cultures: stimulation by glucocorticoids.

Fibrinogen synthesis was investigated in cultures of chicken embryo hepatocytes initiated and maintained in chemically defined, serum-free medium. 11-Hydroxy glucocorticoids caused a 3-fold stimulation of fibrinogen synthesis. Half-maximal stimulation was achieved with 1 nM corticosterone or hydrocortisone, as compared with only 0.1 nM dexamethasone. Increased fibrinogen production in the presence of these glucocorticoids was characterized by a 4-hr delay in onset, a sensitivity to actinomycin D, and a requirement for the continuous presence of the steroid. Crossed immunoelectrophoresis permitted analysis of the simultaneous effects of glucocorticoids on the synthesis of more than 20 plasma proteins secreted in culture. The absence of an effect on the synthesis of most of these proteins was in sharp contrast to the 3-fold increase in fibrinogen production. Sera from a variety of animals also stimulated an increase in fibrinogen synthesis that was similar in degree but less specific than that due to glucocorticoids and that partially masked the response of the cells to the steroid hormones. The presence of an anticoagulant in the medium was found to be necessary for detection of the fibrinogen secreted in culture. Although insulin was routinely included in the chemically defined medium, the cells synthesized fibrinogen and responded to glucocorticoids in the absence of hormonal supplementation of the medium. These findings are consistent with the thesis that variations in glucocorticoid levels contribute to the regulation of fibrinogen production in the intact animal.


Amino acid sequence of a progesterone-binding protein.

The amino acid sequence of blastokinin, also called uteroglobin, has been determined by a combined study of both the intact native molecule and the peptide fragments resulting from tryptic and chymotryptic digestions. Sequence analyses performed by automated methods and by sequential digestion with leucine aminopeptidase and carboxypeptidase Y demonstrate that blastokinin is a dimer of identical 69-amino acid subunits held together in parallel orientation by two disulfide bridges at positions 3 and 68. The polypeptide chains are further characterized by the absence of tryptophan residues and by single residues of histidine and tyrosine at positions 8 and 21, respectively. Six of eight amino acids, positions 17--24, near the progesterone binding site of blastokinin contain a hydroxyl group. Knowledge of the chemistry of this receptor site should allow better perspectives of the chemistry of molecules in normal tissues that are dependent on progesterone for growth and development, as well as compounds that could act as cancer antagonists for endocrine therapy of hormone-dependent tumors.


Topographic study of the cell surface of micrococcus radiodurans.

The paracrystalline outer membraneous layer (HPI layer) of Micrococcus radiodurans has been investigated by negative- and positive-staining electron microscopy and subsequent digital image processing. The subunit structure of the major HPI layer protein complex and the lipid-protein distribution in the plane of the membrane have been determined. The HPI layer was found to be highly asymmetric in a transmembrane direction, with the major protein complex only partly penetrating into a lipid-containing backing layer intimately associated with it.


Long-term growth and differentiation of Xenopus oocytes in a defined medium.

Xenpus laevis oocytes over a size range of 0.15--0.78 mm3 were dissected from their follicles and cultured in a defined medium for up to 28 days. Oocytes grew at average rates of 0.021 mm3.day-1 in the absence of insulin and 0.030 mm3.day-1 in the presence of insulin. The latter average growth rate corresponds to the fastest growth rate reported to date for oocytes in vivo. Oocytes grown in vitro can reach a size of at least 1.43 mm3, which is larger than the maximum size generally found in vivo. During growth in vitro; oocytes also acquire both a normal pigment pattern and, once they reach about 0.7 mm3, the ability to undergo complete maturation as a response to externally applied progesterone. These results show that Xenopus oocytes freed of their follicular investments are able to grow and differentiate in vitro.


Complex population of mRNA sequences in large polyadenylylated nuclear RNA molecules.

Polyadenylylated heterogeneous nuclear RNA [poly(A)-hnRNA] from mouse brain was subjected to electrophoresis in agarose gels containing CH3HgOH, and molecules larger than 8 kilobases or 13 kilobases were recovered. cDNA was then transcribed from polyadenylylated RNA fragments cleaved from these large molecules. The resulting cDNA hybridized almost to completion with poly(A)-mRNA isolated from mouse brain polysomes. From the hybridization kinetics of this cDNA with its template RNA, it was estimated that the sequence complexity of the 3'-proximal sequences (of the same average size as mRNA) of the greater than 8 kilobase poly(A)-hnRNA was about 57,000 kilobases. The sequence complexity of poly(A)-mRNA, estimated from the template-driven hybridization kinetics of its respective cDNA, was about 110,000 kilobases. It is concluded that most, if not all, of the 3'-proximal sequences of large poly(A)-hnRNA molecules are homologous with mRNA in the mouse brain and that at least 40,000 different mRNA sequences (or portions of mRNA sequences) are represented in the 3'-proximal sequences of greater than 8 kilobase poly(A)-hnRNA.


Amplified dihydrofolate reductase genes are localized to a homogeneously staining region of a single chromosome in a methotrexate-resistant Chinese hamster ovary cell line.

Methotrexate-resistant Chinese hamster ovary cells selected for high resistance by progressive increments of methotrexate in the culture medium have levels of dihydrofolate reductase (tetrahydrofolate dehydrogenase, 7,8-dihydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) 200 times that of sensitive cells and a corresponding increase in the number of copies of the dihydrofolate reductase gene. The resistant cells contain an expanded region on the second chromosome (homogeneously staining region) that is not present in sensitive cells. In situ hybridization of DNA complementary to dihydrofolate reductase mRNA shows that the dihydrofolate reductase genes are specifically localized to the homogeneously staining region of this chromosome in the resistant cells.


Monoclonal antibody defining a stage-specific mouse embryonic antigen (SSEA-1).

A monoclonal antibody derived by fusion of mouse myeloma cells with spleen cells from a mouse immunized with F9 teratocarcinoma cells is described. This antibody, which reacts with embryonal carcinoma cells of mouse and human origin and with some preimplantation stage mouse embryos, defines an embryonic stage-specific antigen. This stage-specific antigen (SSEA-1) is first detected on blastomeres of 8-cell stage embryos. Trophectodermal cells are transitorily positive; however, each cell in the inner cell mass eventually expresses this antigen.


Gene duplication in tetraploid fish: model for gene silencing at unlinked duplicated loci.

Several groups of fishes, including salmonids and catastomids, appear to have originated through genome duplication events. However, these two groups retain approximately 50% of the loci examined as functioning duplicates, despite the passage of 50 million years or more of mutation and selection. Although other effects are not excluded, this apparently slow rate of duplicate silencing can be explained in terms of the effects of selection against defective double homozygotes to unlinked duplicates. We have derived a computer simulation of genetic drift that affords direct evaluation of the effects of population size (N), mutation rate (micron), initial allele frequencies, back mutation, fitness, and time on the probability of fixation for null alleles at unlinked duplicate loci. The results show that this probability is approximately linearly related to population size for N greater than or equal to 10(3). Specifically, for naive populations, the time for 50% probability of gene silencing is approximately equal to 15N + micron-3/4 generations. The retention of 50% of the loci as functional duplicates may therefore result from the large effective size of salmonid and catastomid populations. The results also show that, under most conditions for populations of 2000--3000 or larger, unlinked duplicate loci will be sustained in the functional state longer than tandem (linked) duplicates and hence are available for evolution of new functions for a longer time.


Indirect estimates of mutation rates in tribal Amerindians.

Three different formulations have been used to estimate the average rate/locus/generation with which mutation results in electrophoretically detectable variants of 28 proteins in 12 tribal Amerindian populations. All methods are indirect--i.e., they assume a reasonable approximation to equilibrium between mutation and loss of mutants from the population--and are based on the further assumption that the biochemical traits under consideration are essentially neutral in their phenotypic effects. Despite the fact that the methods draw on somewhat different aspects of the available data, there is satisfactory agreement between them, the average of the three estimates being 1.6 X 10(-5)/locus/generation. This average does not encompass mutation that does not result in a change in electrophoretic mobility or that results in loss of enzyme activity. It is noteworthy that this estimate is in satisfactory agreement with a recent estimate by Neel and Thompson [Neel, J. V. & Thompson, E. A. (1978) Proc. Natl. Acad. Sci. USA 75, 1904--1908] of the mutation pressure necessary to maintain the number of "private" genetic polymorphisms being encountered in Amerindian tribes, if selection is not a factor.