The centromere and promoter factor 1 of yeast contains a dimerisation domain located carboxy-terminal to the bHLH domain.

CPF1 is a basic helix-loop-helix (bHLH) protein required for optimal centromere function and for maintaining methionine independent growth in yeast. In this work, we show that the region carboxy-terminal to the bHLH domain of CPF1 is essential for CPF1 function in the cell and for dimerisation of CPF1 in solution. The C-terminus of CPF1 contains a potential long amphipathic helix with a hydrophobic face which could provide a suitable protein:protein interface. Point mutations in residues forming this hydrophobic face are sufficient to weaken the interaction between the protein and DNA. By fusing the DNA binding domain or the transcriptional activation domain of GAL4 to the C-terminal 87 amino acids of CPF1, we show that this region is sufficient for mediating protein:protein interactions in vivo. The C-terminal domain of CPF1 can be replaced by the leucine repeat region of the bHLH-ZIP protein USF and the hybrid CPF1-USF protein functions in vivo to provide normal centromere function and methionine independent growth. However, the CPF1-USF hybrid protein is unable to interact with CPF1 suggesting that a dimer of CPF1 is sufficient for maintaining methionine independent growth and normal centromere function.


Control of mouse U1a and U1b snRNA gene expression by differential transcription.

The expression of mouse embryonic U1 snRNA (mU1b) genes is subject to stage- and tissue-specific control, being restricted to early embryos and adult tissues that contain a high proportion of stem cells capable of further differentiation. To determine the mechanism of this control we have sought to distinguish between differential RNA stability and regulation of U1 gene promoter activity in several cell types. We demonstrate here that mU1b RNA can accumulate to high levels in permanently transfected mouse 3T3 and C127 fibroblast cells which normally do not express the endogenous U1b genes, and apparently can do so without significantly interfering with cell growth. Expression of transfected chimeric U1 genes in such cells is much more efficient when their promoters are derived from a constitutively expressed mU1a gene rather than from an mU1b gene. In transgenic mice, introduced U1 transgenes with an mU1b 5' flanking region are subject to normal tissue-specific control, indicating that U1b promoter activity is restricted to tissues that normally express U1b genes. Inactivation of the embryonic genes during normal differentiation is not associated with methylation of upstream CpG-rich sequences; however, in NIH 3T3 fibroblasts, the 5' flanking regions of endogenous mU1b genes are completely methylated, indicating that DNA methylation serves to imprint the inactive state of the mU1b genes in cultured cells. Based on these results, we propose that the developmental control of U1b gene expression is due to differential activity of mU1a and mU1b promoters rather than to differential stability of U1a and U1b RNAs.


Splicing signals in Drosophila: intron size, information content, and consensus sequences.

A database of 209 Drosophila introns was extracted from Genbank (release number 64.0) and examined by a number of methods in order to characterize features that might serve as signals for messenger RNA splicing. A tight distribution of sizes was observed: while the smallest introns in the database are 51 nucleotides, more than half are less than 80 nucleotides in length, and most of these have lengths in the range of 59-67 nucleotides. Drosophila splice sites found in large and small introns differ in only minor ways from each other and from those found in vertebrate introns. However, larger introns have greater pyrimidine-richness in the region between 11 and 21 nucleotides upstream of 3' splice sites. The Drosophila branchpoint consensus matrix resembles C T A A T (in which branch formation occurs at the underlined A), and differs from the corresponding mammalian signal in the absence of G at the position immediately preceding the branchpoint. The distribution of occurrences of this sequence suggests a minimum distance between 5' splice sites and branchpoints of about 38 nucleotides, and a minimum distance between 3' splice sites and branchpoints of 15 nucleotides. The methods we have used detect no information in exon sequences other than in the few nucleotides immediately adjacent to the splice sites. However, Drosophila resembles many other species in that there is a discontinuity in A + T content between exons and introns, which are A + T rich.


Oligodeoxynucleotide-directed photo-induced cross-linking of HIV proviral DNA via triple-helix formation.

The HIV proviral genome contains two copies of a 16 bp homopurine.homopyrimidine sequence which overlaps the recognition and cleavage site of the Dra I restriction enzyme. Psoralen was attached to the 16-mer homopyrimidine oligonucleotide, d5'(TTTTCT-TTTCCCCCCT)3', which forms a triple helix with this HIV proviral sequence. Two plasmids, containing part of the HIV proviral DNA, with either one (pLTR) or two (pBT1) copies of the 16-bp homopurine.homopyrimidine sequence and either 4 or 14 Dra I cleavage sites, respectively, were used as substrates for the psoralen-oligonucleotide conjugate. Following UV irradiation the two strands of the DNA targeted sequence were cross-linked at the triplex-duplex junction. The psoralen-oligonucleotide conjugate selectively inhibited Dra I enzymatic cleavage at sites overlapping the two triple helix-forming sequences. A secondary triplex-forming site of 8 contiguous base pairs was observed on the pBT1 plasmid when binding of the 16 base-long oligonucleotide was allowed to take place at high oligonucleotide concentrations. Replacement of a stretch of six cytosines in the 16-mer oligomer by a stretch of six guanines increased binding to the primary sites and abolished binding to the secondary site under physiological conditions. These results demonstrate that oligonucleotides can be designed to selectively recognize and modify specific sequences in HIV proviral DNA.


Interaction of N-terminal domain of U1A protein with an RNA stem/loop.

The U1A protein is a sequence-specific RNA binding protein found in the U1 snRNP particle where it binds to stem/loop II of U1 snRNA. U1A contains two 'RNP' or 'RRM' (RNA Recognition Motif) domains, which are common to many RNA-binding proteins. The N-terminal RRM has been shown to bind specifically to the U1 RNA stem/loop, while the RNA target of the C-terminal domain is unknown. Here, we describe experiments using a 102 amino acid N-terminal RRM of U1A (102A) and a 25-nucleotide RNA stem/loop to measure the binding constants and thermodynamic parameters of this RNA:protein complex. Using nitrocellulose filter binding, we measure a dissociation constant KD = 2 x 10(-11) M in 250 mM NaCl, 2 mM MgC2, and 10 mM sodium cacodylate, pH 6 at room temperature, and a half-life for the complex of 5 minutes. The free energy of association (delta G degrees) of this complex is about -14 kcal/mol in these conditions. Determination of the salt dependence of the binding suggests that at least 8 ion-pairs are formed upon complex formation. A mutation in the RNA loop sequence reduces the affinity 10 x, or about 10% of the total free energy.


Characterization of antibodies against methyl-pppN cap structure: plant U3 small nucleolar RNA is recognized by these antibodies.

In eukaryotes, many small nuclear RNAs contain either a trimethylguanosine cap structure of a gamma-monomethyl (me) cap structure. Previously, we reported the characterization of anti-mepppG antibodies which recognize methyl-capped RNAs with G as the initiation nucleotide. We report here the preparation of antibodies against mepppN cap structure. Anti-mepppN antibodies recognized only mepppN from a mixture of mepppN and pppN and immunoprecipitated mepppA-capped U3 small nucleolar RNA from a mixture of cowpea cell RNAs. These anti-mepppN antibodies recognized methylated nucleoside triphosphates (mepppA, mepppC, mepppG and mepppU) with nearly equal efficiency; however, these antibodies did not recognize methyl phosphate or methylated mononucleotides. These antibodies will be useful in the identification and characterization of all methyl-capped RNAs no matter which is the initiation nucleotide.


Multiple octamer binding sites in the promoter region of the bovine alpha s2-casein gene.

Using a set of overlapping oligonucleotides from the promoter region of the bovine alpha s2-casein gene we have identified two nuclear factors which probably are involved in expression of this gene and the related calcium sensitive alpha s1- and beta-casein genes. One of these factors which was present in extracts of all tissues that have been tested including Hela cells turned out to be the octamer binding protein OCT-1. Oct-1 binds with different affinity to 4 sites at positions centred around -480, -260, -210 and -50. The strongest of these 4 binding sites, the one around position -50, is highly conserved in all calcium sensitive caseins of mouse, rat, rabbit and cattle. The other nuclear factor (MGF, mammary gland factor) which is specifically expressed in the mammary gland, binds to a site around position -90. This binding site is also highly conserved in all calcium sensitive caseins of mouse, rat, rabbit and cattle.


Cloning of the gene for the 73 kD subunit of the DNA polymerase alpha primase of Drosophila melanogaster.

We have isolated both cDNA and genomic clones for the 73 kDa subunit of the DNA polymerase alpha primase of Drosophila melanogaster. Analysis of these clones has identified an open reading frame of 1959 bases coding for a protein of 72.5 kDa. Northern analysis has shown the mRNA for the gene to be approximately 2.5 kb, and comparison of the cDNA and the genomic clones shows that the coding region of the gene lacks introns. The 5' end of the transcript has been mapped by primer extension, and the position of the gene in the genome mapped using in situ analysis. Computer analysis has been carried out on both coding and non coding regions of the gene. The protein sequence shows some homology to the analogous subunit in the S. cerevisiae DNA polymerase alpha, however a search of the data banks failed to reveal other homologies, or provide any clues as to the function of the protein. Analysis of the non-coding regions indicates some potential control regions for the gene. The 73 kDa protein has been overproduced, but a preliminary analysis failed to reveal any enzymatic activities.


An assessment of neural network and statistical approaches for prediction of E. coli promoter sites.

We have constructed a perceptron type neural network for E. coli promoter prediction and improved its ability to generalize with a new technique for selecting the sequence features shown during training. We have also reconstructed five previous prediction methods and compared the effectiveness of those methods and our neural network. Surprisingly, the simple statistical method of Mulligan et al. performed the best amongst the previous methods. Our neural network was comparable to Mulligan's method when false positives were kept low and better than Mulligan's method when false negatives were kept low. We also showed the correlation between the prediction rates of neural networks achieved by previous researchers and the information content of their data sets.


RecA protein promotes rapid RNA-DNA hybridization in heterogeneous RNA mixtures.

The nucleoprotein filament formed by the RecA protein of Escherichia coli on single-stranded DNA catalyzes the hybridization of RNA transcripts with single-stranded DNA sequences at 37 degrees C, in vitro. RecA protein rapidly promotes hybridization, even when noncomplementary RNA is in a millionfold nucleotide excess over hybridizing RNA, and in a thousandfold nucleotide excess over hybridizing single-stranded DNA. Heterologous double-stranded DNA and RecA-coated noncomplementary single-stranded DNA are also poor competitors of RNA transcripts produced in vitro. Since large excesses of noncomplementary RNA fail to inhibit sharply the hybridization reaction by RecA protein under mild, non-degradative conditions, the reaction may be useful in the identification and isolation of transcripts produced in vivo.


Pathophysiology of lung cancer.

Cigarette smoking is responsible for approximately 30% of all cancer deaths. Smoking accounts for 85% of lung cancer cases in men and 75% in women. There are about 38 million former cigarette smokers and about 50 million smokers in the United States today. Smoking rates are higher among blacks, blue collar workers, and less educated people. More than 140,000 lives will be lost to cancer each year because of tobacco smoking. All cancers caused by cigarette smoking could be prevented. It is hoped that public education, smoking cessation programs, and efforts to eliminate carcinogens in the work environment will impact the future incidence of new lung cancer cases. As preventive measures continue, refinement in the diagnosis and treatment of cancer must continue to advance. The recognition of any one of cancer's seven warning signals and prompt subsequent action could lead to earlier detection and a chance for 3- and 5-year survival rates to improve. With medical and research progress, clinical concerns have grown beyond addressing only the patient's physical needs to include important issues such as employment and insurance needs and the psychosocial needs of both the patient and the family as they learn to live with cancer.


Diagnostic testing for patients with lung cancer.

Lung cancer is the most common cause of cancer death for men and women in the United States. The diagnosis of lung cancer is cause for fear and anxiety in the general population because more than 85% of people with lung cancer are dead within 5 years. A diagnosis of lung cancer begins with a thorough health assessment followed by appropriate diagnostic testing. The nurse has the greatest amount of interaction with the patient and can help to facilitate the diagnostic process in a manner that renders it less stressful and effective. The nursing process of assessment, diagnosis, planning, goal setting, and evaluation guides the prepared nurse in accomplishing this task.


Smoking.

Cigarette smoking remains a major health problem in not only the United States but the world. The dependency-producing effects of nicotine are well documented. Primary prevention, preventing the initiation of smoking, is receiving increased attention in the field of health education. Secondary prevention, smoking cessation, is showing promising results. Perhaps the goal of a smoke-free America by 2000 is not a "pipe dream" after all.


Trends in radiation therapy for the treatment of lung cancer.

Two methods of radiotherapy delivery, external beam radiotherapy and brachytherapy, are important curative and palliative modalities for treating lung cancer. In situations when cure is not possible, radiotherapy may be effective in controlling lung cancer cell growth. Investigative use of other ways of delivering radiation therapy, CHART, intraoperative radiotherapy, remote afterloading brachytherapy, and hyperthermia, are currently under way. Nursing diagnoses and care are based on assisting the patient in understanding the rationale for receiving radiation therapy, the way in which radiation therapy is administered, and its potential side effects.


Surgical resection of lung cancer.

Surgery remains the treatment of choice for patients with lung cancer who demonstrate resectable tumors. The type of surgical procedure performed depends on the degree of metastasis and the functional lung capacity of the patient. In addition to problems common to all surgical patients, complications such as cardiac arrhythmias, pulmonary embolus, respiratory failure, bronchopleural fistula, and empyema may occur. Although survival statistics for patients with lung cancer remain poor, the common denominator in patients that have survived 5 years is surgical resection.


Psychosocial implications of lung cancer.

Patients with lung cancer who are encouraged and permitted to verbalize their feelings by a staff that is interested, empathetic, and nonjudgmental are better able to overcome feelings of anxiety and fear, and they progress through the stages of the grieving process more easily. Communications between the lung cancer patient and the multidisciplinary staff should occur freely and without restraint. Unrealistic expectations made of the patient who is struggling to cope will almost certainly increase anxiety. Interventions must address coping responses of the patient and family living with lung cancer. Caregivers working with patients whose diagnoses are not favorable must examine their own feelings regarding terminal disease states and death before the entire cancer experience can be discussed openly and comfortably by the patient, family members, and health care team. The focus of care for families and patients living with lung cancer should be on care rather than cure.


Nursing care of the terminal lung cancer patient.

Care of the terminal lung cancer patient will be more effective when a multidisciplinary approach is used. Planning for terminal care should not be delayed until the last few hours or days of life. Hospice care offers the terminal lung cancer patient an alternative to dying in a hospital or nursing home. Caring support to alleviate pain and prevent suffering is the goal of nursing care for the terminal cancer patient. Nursing interventions should be directed toward allowing the patient to retain decision-making authority in care for as long as possible.


Vision and vision loss.

To provide supportive and effective care to people who must adapt to blindness or visual impairment, nurses and other health care professionals have a responsibility to be knowledgeable about the unique effect of ophthalmic disorders on the body, spirit, and mind. It is also evident that nurses must clearly understand their own emotions and social reactions to blindness and visual loss so that they can more clearly assist their clients through adaptation.


Knowledge deficit in the ophthalmic surgical patient.

This case history illustrates some important aspects of the informational needs of ophthalmic surgery patients. As is true with many ophthalmic patients, this patient had a relatively high level of anxiety regarding his potential loss of vision postoperatively. This concern is magnified in a monocular patient. The nurse must help these patients put this concern in the proper perspective by providing accurate information. The nurse who performs such extensive preoperative teaching takes on a role that entails a great deal of responsibility. A planned program of information with written objectives and an outline of the important information to include will help the nurse provide a high level of care in meeting the knowledge needs of the patient. It is not necessary, or even desirable, to develop a plan for each individual patient. A written outline of important and necessary information for each type of ophthalmic surgical procedure provides a means of assuring that the teaching plan is complete and accurate. The information in the teaching plan should be validated by other physician and nurse colleagues. A written plan can save time once it is developed, because the nurse can follow the standard plan, modifying the presentation to meet each patient's specific needs as necessary. The patient indicated feeling somewhat overwhelmed with information when faced with his ophthalmic surgery. It is very important to ensure that the patient and appropriate significant others get both verbal and written information in these situations. The written information gives the patient and his or her family a reference to use when they return home and begin to assimilate more of the information given to them by the nurse. The patient in this case history and his wife both referred to the written instructions several times before and after the operation to verify certain information. The written materials presented information at an appropriate reading level and had large well-spaced print. Repetition (whether verbal or in written format) is important because it reinforces important aspects of the necessary information. The nurse at the surgical facility repeated the postoperative requirements to the patient and his wife before they left the center and made sure that they had the written instructions as well. The nurse demonstrated the necessary motor skills and gave the patient and his wife the opportunity to return the demonstration.


Nursing care of the cataract patient: today's outpatient approach.

Total cataract patient care encompasses nursing assessment, clinical management, emotional support, and the accessibility of the nurse to the patient. Because ophthalmic nurses develop a close relationship with the cataract patient, they are often the first health care professional the patient calls for advice. Patient education and adequate time to listen and respond are integral components in an outpatient cataract surgical approach. All aspects of the nursing care of the cataract patient provide challenge and satisfaction as the ophthalmic registered nurse experiences surgery with the patient and supervises the return to improved vision and quality of life. The nurse must always remember that there is a whole person attached to the eye. Although ophthalmic nursing is specialized and highly technical, patience, empathy, and encouragement are essential in the care of the patient before, during, and after cataract surgery.


Diabetic retinopathy.

The risk of blindness is 25 times greater in diabetics than nondiabetics. Medical, laser, and surgical interventions have the potential to enhance greatly the prognosis of maintaining useful vision throughout life. Patient education is paramount to improve comprehension of the condition, recommended treatment modalities, and compliance with prescribed regimens. Nursing assessments and interventions related to anxiety, discomfort, ineffective coping mechanisms, and immobility add a quality link in the multidisciplinary approach surrounding the delivery of care to patients with diabetic retinopathies.


Macular degeneration.

With the "graying of America," the patient population at risk for developing ARMD will continue to grow. As researchers continue to study the cause, pathologic changes, and risk factors associated with the development of this disease, preventive measures and improved treatment options will become available. The education of ARMD patients in the recognition of signs of the disease for early treatment, treatment options, and the availability of resources is essential for the nurse caring for this population. Adjustment to visual loss will be an ongoing process, during which the nurse can be a source of support, guidance, and encouragement, as patients assimilate newly acquired behaviors and roles into their self-image.


Choroidal melanoma.

Choroidal melanoma is a rare and deadly cancer. Nursing care for these patients involves ophthalmic clinical expertise as well as psychosocial and emotional support. Although past research has been helpful in determining the prognosis of these patients, it is impossible to predict with certainty which patients have tumors or nevi that will grow, will compromise their vision, or will kill them. Providing emotional support, establishing a good rapport with the patients and their support persons, and encouraging patients to schedule and adhere to their mutually agreed on follow-up appointments are nursing interventions that may save or prolong a patient's life.


Worldwide blindness.

Blindness affects approximately 42 to 52 million people worldwide. This article examines the major causes of blindness, including cataract, trachoma, glaucoma, onchocerciasis, nutritional deficiencies, and ocular trauma. Numerous case studies supplement the text.


[Celiac disease and autoimmunity].

Immune mechanisms have been invoked to explain coeliac disease and associations between this and other immunologically mediated diseases have been described. A direct relationship proposed is that coeliac disease may be associated with a range of autoimmune disease through the formation of immune complexes in the small intestine. It's more probable a common origin in an inherited predisposition to hypersensitive immuno responses to extrinsic antigens or auto-antigens. The association between coeliac disease and particular histocompatibility antigens was recognised.


[The follow-up of malformation uropathies diagnosed "in utero"].

Prenatal diagnosis and postnatal follow-up of urinary tract congenital malformations are discussed. Among 9501 overall births, 25 newborns with urinary tract congenital malformations were born (2.6 x 1,000). Twenty cases had been diagnosed "in utero" by ultrasound scan (4 cases of Potter sequence, 2 cases of prune-belly anomaly, 3 cases of polymalformed infants with urinary involvement, 10 cases of hydronephrosis, 1 case of ectopic kidney). In 8 newborns a surgical treatment was successfully performed. Eight newborns died and in other 4 cases clinical and ultrasonographic are not yet fulfilled. In 2 cases the prenatal diagnosis of urinary tract malformations was not confirmed by the postnatal evaluation. Our experience shows that the prenatal diagnosis of congenital malformations of urinary tract is particularly useful, even considering the opportunities of perinatal management and postnatal surgical treatment in several cases.


[The microbiological exam of the urine: what significance in urinary tract infections?].

11,829 urine cultures, coming from the Pediatrics Department of Florence and other hospital divisions for adults in the period 1st of July-31st of December 1990, have been examined in the Bacteriology and Virology Laboratory of the University Hospital of Florence. Besides illustrating various methods of drawing, preservation and transport of the urinary specimen, the authors showed the incidence of bacterial species responsible of urinary tract infections (U.T.I.). E. coli was showed to be the most frequently isolated bacterial strain, followed by Streptococcus faecalis and Proteus indole negative. The incidence of fimbriated E. coli infections was studied in pediatric and adult patients with urinary tract infections; a higher isolation frequency of fimbriated E. coli was showed in pediatric patients and in these patients the correlation was studied between the presence of fimbriated E. coli and the severity of infection (pyelonephritis, recurrent U.T.I.). The percentages of resistance of the isolated strains against the most common chemotherapies was also showed, studying their variations, for some chemotherapies, during about twenty years.


[The use of the computer in the neonatal intensive therapy unit: the current and prospective aspects].

The Authors assert that computer can give an adjunctive value to our abilities, improve the punctuality of own service, lighten the duties of routine (leaving free time for own-self or for adjournment). We have noticed a gradual but continuous increase of the use of the computer in the last years in hospital particularly in the Neonatology department and in the NICU, even because in these departments the data to compare are numerous. In the Brindisi's NICU since 1/7/1986 there has been a process of progressive increase of the use of the computer, based on three directions: filing data of the patients, computer-assisted management of the treatment of RDS, computer-assisted follow-up of the risk-baby, and management of the resources. Moreover are reported possibilities of future applications, as records of diagnosis and helped therapy, interface with medical equipment, linking with databank and with the hospital's mainframe.


[Abdominal migraine simulating acute abdomen].

Migraine is a variant of headache often associated with neurologic and/or vegetative symptoms mainly represented by abdominal pain. This symptom may occur some hours before migraine manifestation and in these cases the differential diagnosis with other clinical conditions characterized by abdominal pain, which is very common during childhood, may be difficult. Abdominal migraine can be diagnosed only if a close relationship is demonstrated between the abdominal symptoms and migraine. Alteration of consciousness is a well known feature during migraine and in some cases EEG may show SNC involvement during the attack. We report a case of abdominal migraine attack evaluated by EEG. The patient, a 10 years old male, presented with a picture of acute abdomen. An EEG performed at the occurrence of the early headache symptoms and of consciousness alteration demonstrated a pattern characterized by a lowering in the electric activity on the left hemisphere. Some hours later he developed a clear migraine followed by disappearance of the abdominal symptoms. This observation confirms the possible association of migraine with a picture simulating an acute abdomen and suggests that the differential diagnosis with a true surgical condition may be achieved by the observation of the progression of symptoms and by early evaluation of patient with EEG.


[Otitis media in childhood: a critical review of the literature].

Infection of the middle ear is one of the most common childhood illnesses accounting for one-third of the pediatrics practice during the first five years of life. Therefore treatment and prevention of the otitis media are of considerable importance. A review of the literature of the otitis media during the pediatric age is reported. In fact in the last years a large amount of knowledge, sometimes referring discordant opinions, has been acquired. The Authors report epidemiology, anatomy, pathology, physiology, microbiology, classification, clinical data diagnosis and therapy of the otitis media. Common conditions of the middle ear (normal, acute otitis media, chronic otitis media, recurrent otitis media) are described. In particular acute otitis media, otitis media with effusion, perforation of the tympanic membrane, fluid level in the middle ear, severe retraction or bulging of the tympanic membrane are pointed out in color-photographs.


[An epidemiological study of skin tuberculin positivity in the province of La Spezia in 1988-1991: an evaluation of the results in 3932 cases].

In recent years (1989-1991) the author has tested for positivity of tuberculosis (with Tine-Test) 3.932 children, belonging to two age groups: 1-3 and 10-11 years. The results of positivity to the cutireaction (0% and 0.32% respectively) were lower, in comparison to other published reports.


[The catarrhal child].

The first seven years of a child's development are often described as the catarrhal stage. This is because of the increased incidence of upper respiratory tract infections. Nasal obstruction in the children is common and symptoms are often distressing. The authors report a rational approach to this problem to produce effective treatment of recurrent nasal obstruction. In particular clinical features, diagnosis, and therapy of recurrent rhinitis, adenoid hypertrophy, and tonsillar obstruction are described. The indications for adenoidectomy, tonsillectomy or adenotonsillectomy has been questioned.


[Pulmonary hemosiderosis induced by cow's milk proteins: a discussion of a clinical case].

Pulmonary hemosiderosis (PH), a rare pathology, usually occurring during infancy and childhood, is characterized by numerous and repeated intra-alveolar bleedings, interstitial iron build-up with consequent progressive fibrosis and severe anemia. PH can be basically divided into 3 different categories: Primitive or idiopathic, involving a primitive deficit of antioxidizing enzymes in the erythrocytes in genetically predisposed subjects; Secondary, subsequent to chronic pneumopathy or cardiopathy; Associated with various pathologies including collagenopathies, glomerulonephritis, myocardiopathies, diabetes, steatorrhea, tireotossicosis. A particular type of Pulmonary Hemosiderosis, associated with allergy to cow's milk, has been described for the first time by Heiner. We present in this paper our personal experience of a young patient suffering from pulmonary hemosiderosis induced by cow's milk protein.


[The Schönlein-Henoch syndrome with testicular involvement: a report of 4 cases].

The authors report about four children with Schönlein-Henoch purpura in whom the clinical picture has been characterized by an unusual localization, the testicular involvement. The main clinical aspects of this feature are illustrated and the approach to its diagnosis and its management is discussed.


[Dysplasia epiphysealis capitis femoris (Meyer's disease). An emergent pathology from the echographic screening of congenital hip dysplasia].

The authors present a case of Meyer disease. The knowledge of this pathology, emerging from the ultrasonic screening of the hip, is useful to the pediatrician in the differential diagnostic argument.


[Fukuyama-type congenital muscular dystrophy with the presence of ocular anomalies].

The authors report a case with Fukuyama type congenital muscular dystrophy (FCMD) and severe ocular abnormalities. Muscular dystrophy was confirmed by EMG, high muscle enzyme value and muscular biopsy. Computed tomography (CT) of the brain at 15 months of life showed mild central and cortical atrophy. Repeated CT scans at 22 and 32 months showed progressive character of the atrophy, with preservation of the cerebellar areas and the central grey matter only. Ophthalmologist examination revealed nystagmus, severe visual deficit, optic nerve atrophy and irregular color of the retina, especially in the peripheric areas. Electroretinography (ERG) was normal, cortically evoked visual responses (PEV) were absent. The association of congenital muscular dystrophy with brain changes and ocular abnormalities were found in FCMD, muscle-eye-brain disease (MEB) and Walker-Walburg syndrome (WWS). Our report, according to the recent literature, suggests that ocular lesions are caused by the same mechanism that provokes the central nervous system anomalies. It is probably of genetic origin: FCMD, MEB and WWS could be development abnormalities with a continual spectrum of disease severity.


Separation of tendon ends after Achilles tendon repair: a prospective, randomized, multicenter study.

Fifty-seven patients treated for an acute rupture of the Achilles tendon were studied. The patients were randomized into a Mason suture technique or a reinforced continuous six-strand suture technique, and markers were attached to each tendon end perioperatively. The postoperative separation of the markers was studied by repeat radiographic examination. Despite immobilization, separation developed after a biphasic course, and after 7 weeks the mean separation was 10.5 mm. No difference was found between the two techniques. We attempt to correlate the separation to the clinical outcome, examined at 1 year follow up.


[The Silver-Russel syndrome].

The authors report a case of Silver-Russel syndrome with severe deficit growth observed since intrauterine life. They describe the major features, that are constant and the minor features, that are variable and numerous. The features not always are present at birth. The A. exclude in this case a genetic cause and suggest a possible motherly cause.


Immediate plate fixation of highly comminuted femoral diaphyseal fractures in blunt polytrauma patients.

From January 1982 through December 1988, 150 patients with 153 Winquist Class III and IV comminuted diaphyseal femur fractures due to high energy blunt trauma were treated with immediate plate fixation. A total of 260 major general surgical systems were injured in 150 patients. Forty-nine patients did not have adequate preoperative spine radiographs due to positioning or time factors. Nineteen patients had spine fractures; nine were diagnosed post-femoral fixation. The average injury severity score (ISS) was 22.7. Three patients died (2%). Our institution predicted mortality with this ISS for patients without pelvic or femur fractures at 15% (P = .0003). Six patients moved to other states and three were lost to follow up due to noncompliance. One of us reviewed 141 fractures in 138 patients at a minimum of 12 months follow up and completion of treatment. Forty-nine fractures were open; 8 grade I, 25 grade II, 10 grade IIIA, 4 IIIB, 2 IIIC. A total of 153 pelvic or ipsilateral major orthopedic injuries were present in 141 fractures. An additional 188 major associated orthopedic injuries were noted. The average time to union was 17.2 weeks. One plate was applied in 11 degrees of varus. Five plates failed from fatigue and five from repeat traumas. Seven plate failures were rodded and healed within 8 weeks. There was one persistent nonunion. One fracture, open IIIC, became infected after uniting. One patient has 110 degrees of knee motion and 140 fractures have greater than 130 degrees of knee motion. Plate fixation is a safe technique for immediate femoral stabilization in the face of high energy blunt trauma. Failures occur late and are easy to reconstruct. Intramedullary nails are the preferred method of reconstruction. Ultimate knee function is excellent. Infection rates (1/49) in open fractures are acceptably low.


[Early autism and congenital muscular dystrophy: a clinical case].

The authors describe the case of a twelve-year-old patient presenting early autism associated with congenital muscular dystrophy--subtype IV, according to the subclassification of Fukuyama (slight mental retardation, ability to walk, muscle pseudohypertrophy). To our knowledge, this association has never been reported. Several factors may have played a causative role in the development of an autistic disorder in the patient. The authors suggest the following as the most significant ones: disharmonious personality, weak emotional structure, inadequate primary relation with the mother, poor environmental influences, frustrations encountered because of the muscular disorder.


Surgical results in anterior cervical discectomy and fusion using a countersunk interlocking autogenous iliac bone graft.

The purpose of this study was to evaluate the surgical results of anterior cervical discectomy and fusion using a countersunk interlocking autogenous iliac bone graft. Two hundred thirty-two patients were followed for an average of 6.8 years. All patients suffered neck and arm pain. Two hundred twenty patients received conservative treatment for at least six months. Overall results were satisfactory in 202 patients (87%) and unsatisfactory in 30 patients (13%). The pseudoarthrosis rate was 6.5% which is significantly lower than previous reports. The premise of this technique is that the interlocking graft prevents migration, promotes fusion by providing immobilization, and restores the height of the interspace. Anterior cervical discectomy and fusion, using a countersunk interlocking autogenous iliac bone graft, is a satisfactory surgical procedure in which successful pain relief is to be expected.


Scaphoid fractures: assessment and treatment.

The scaphoid is the most commonly fractured carpal bone. The fracture pattern and its relationship to the blood supply have significant implications regarding treatment and prognosis. Prompt recognition and treatment are fundamental to successful management.


Avascular necrosis after fracture-separation of the distal end of the humerus in children.

Fracture-separation of the distal end of the humerus in children has been reported infrequently, and may be misdiagnosed as a fracture of the condyle or a traumatic dislocation of the elbow. We discuss eight cases of a seldom reported complication following fracture-separation of the distal end of the humerus. This complication consists of dissolution of the trochlea within three to six weeks postinjury and a defect of the medial or central part of the condyle that develops later. The fractures were severely displaced fracture-separation of the distal end of the humerus with large medial or lateral metaphyseal fragment, but initially misdiagnosed as a fracture of the medial, lateral condyle or a traumatic dislocation of the elbow in six of eight cases. We performed open reduction in six cases because of initial misdiagnosis or because of difficulty in satisfactory closed reduction. We speculated that this complication is due to avascular necrosis of the distal end of the humerus, and that fracture-separation of the distal end of the humerus is more common than reported.


Acute headache. Differential diagnosis and management of the three types.

Headache is a common complaint with many potential causes. Each patient should be thoroughly examined to identify the condition producing the headache. Appropriate treatment varies according to headache type, so therapy should not be initiated until the diagnosis has been established. Dr Diamond reviews the differential diagnosis of headache and techniques for managing its various forms.


Sports injuries. Practical diagnostic and management concerns for primary care physicians.

Both recreational and elite athletes often sustain musculoskeletal injuries. Common problems--muscle cramps, burners (or stingers), and ankle and shoulder injuries--can be managed effectively with certain basic techniques. Initial measures are particularly important in facilitating the injured athlete's rapid return to activity.


Emergency management of acute pain. New options and strategies.

Emergency physicians often encounter patients in pain and may also have to cope with other problems (eg, alcohol intoxication, a patient's stubborn will to drive after the emergency department visit, narcotic "allergy"). Novel approaches can be used to treat these patients. Dr Heller discusses such approaches, including measures for treating patients with drug-seeking behavior (eg, use of nonnarcotic parenteral agents), and describes treatment options for patients with such specific conditions as hypotension, chest pain, and renal colic.


Acute pain in the elderly.

Acute-pain syndromes are common in the elderly. They often occur in association with the degenerative diseases that are likely to affect this age-group. Diagnosis of the specific type of acute pain is made difficult by several factors, including atypical presentation and underreporting. Treatment can be complicated by the polypharmacy that is prevalent among older adults and by age-related physiologic changes. Effective management requires knowledge of the effects of various pharmacologic agents in older adults and of the health and psychosocial status of the individual patient.


Acute and postoperative pain. Management from a primary care perspective.

Most pain is controllable. Patient education and careful intraoperative technique are useful prophylactic measures. Simple analgesics and non-steroidal anti-inflammatory drugs reduce pain, fever, and inflammation and are well tolerated when dosing guidelines are followed carefully. In patients whose pain is not controlled with these measures, the addition of a weak narcotic analgesic is reasonable. If relief is still inadequate, a stronger narcotic alone or in combination with another analgesic may be needed. The advent of patient-controlled analgesia has diminished some of the objections to continuous intravenous infusion of narcotics. Various acute-pain syndromes respond to blockade of the sympathetic or somatic neural pathways. Knowledge of the appropriate anatomic structures and careful technique are mandatory with this method. Moreover, it should be considered only one part of a comprehensive treatment plan.


Orofacial and craniofacial pain. Primary care concerns.

A patient who experiences an acute episode of oral or facial pain is likely to consult a primary care physician. Dr Green reviews the basic information needed to distinguish among the more common types and causes of such pain. Once the pain's source is determined, treatment can be prescribed or an appropriate referral made.


Description of learned response to chronic illness: depressed versus nondepressed self-help class participants.

The purpose of this study was to describe the effectiveness of a community-based health-promotion program that was collaboratively designed and that is currently being implemented by lay persons who have the diagnosis of systemic lupus erythematosus (SLE) and by health professionals. Two groups of SLE self-help course participants contributed data for this theory-guided preexperimental program impact study. Braden's self-help model provided the theoretical framework. The variables addressed were severity of illness, limitations, uncertainty, enabling skill self-efficacy, self-worth, and life quality. The groups consisted of 35 subjects having low depression scores (less than or equal to 77) and 37 with high depression scores (greater than or equal to 272) on a measure having a possible range of scores from 0 to 400. Data were collected at three points: at the beginning of class 1, after class 7 (7 wks later), and two months after completion of the course. A group (2) by time (3) by measures (10) MANOVA analysis procedure was used with a follow up univariate F test and Newman-Keuls multiple comparison procedure. Significant change was evident for the level of depression group and for three interaction effects of group X time, group X measure, and group X time X measure.


Theoretical components of STD counselors' messages to promote clients' use of condoms.

A survey of 34 counselors on sexually transmitted diseases from a large Midwestern state was conducted to compare their responses to promote condom use with clients' attitudes and normative beliefs regarding condoms. Four vignettes were developed using predictor variables about condom use based on the theory of reasoned action (TRA). Results indicate subjects responded minimally to TRA variables mentioned in the vignettes. Moralistic messages about condoms were the most frequent responses reported, followed by those on education, disease prevention, and fear. In some cases information provided was not relevant to behavior described in vignettes. Implications for health care professionals are that messages meant to change behaviors should reinforce clients' attitudes and normative influences, and moralistic or fear messages should be minimized.


Use of breast cancer screening by older Hispanic women.

The purpose of this exploratory study was to provide information on older Hispanic women's access to and use of breast cancer screening services. Interviews were conducted with 150 Hispanic women, 47 to 93 years of age, in a southwestern city. The results indicated that differences in use and compliance with recommended screening guidelines were due primarily to differences in access to the health care system and attitudes about preventive care. Targeted strategies for these women have to be developed and implemented to ensure that they receive the necessary information to avail themselves of breast cancer screening procedures.


Tetanus immunity in older adults.

The frequency of tetanus has declined little in the past decade. The majority of cases occur in persons over 50 years of age. A sample of 225 blood donors, between the ages of 50 and 68, from a mixed rural-suburban county, were tested for tetanus antitoxin levels. Only 14% had protective levels. This low rate indicates the need for increased attention to tetanus immunizations in older adults.


Use of formal community resources by spouse caregivers of chronically ill adults.

This descriptive correlational study examined the use of formal community resources of spouse caregivers of progressively chronically ill individuals. The convenience sample was 61 individuals with a definitive diagnosis of multiple sclerosis and their spouse caregivers. Results indicated that 34.4% of the sample used community resources. Relationships among caregiver demographics, extent of caregiving tasks, subjective burden, perceived uncertainty of the caregiver, functional incapacity of the chronically ill individual, level of social support, and the use of formal community resources were analyzed. Positively correlated (P less than 0.05) with the criterion variable of use of formal community resources were the variables of caregiver age (rpb = 0.342), number of caregiving tasks (rpb = 0.424), caregiver employment level (chi 2 = 8.25), and functional incapacity of the care receiver (rpb = 0.565). Results of discriminate function analysis indicated that three variables, functional incapacity, caregiver age, and number of caregiving tasks, correctly classified users versus nonusers of community resources 83.6% of the time.


A public health quality assurance system.

Quality assurance (QA) systems are commonplace among hospitals. They are even found in home health and health maintenance organizations, but they are less common among public health agencies. This article enumerates the discrepancies between the design of traditional QA and that necessary to meet the needs of a department of health's public health nursing service. It characterizes the subsequent changes that must be inserted into the QA system for it to comply with the mission and services of a public health setting. The system and instruments presented are used in the Baltimore County Department of Health, Public Health Nursing Services.


The concept of poverty.

Although poverty is one of the most familiar and enduring conditions known to humanity, it is an extremely complicated concept to understand. Some researchers view it as a reaction to the stress of being poor, whereas others perceive it as a process of adapting to the condition of poverty. Historical definitions are numerous, but can be classified as relating to either lack of financial income or lower social status. Numerous factors contribute to the concept of poverty, including political, economic, social, and cultural forces. The one that has consistently had the greatest effect on the evolving concept is the passage of time, which encompasses all these forces in a very intricate manner. This author explored the evolution of the concept of poverty to identify relevant themes for consideration in the public health nursing domain.


Accidental poisoning of children: barriers to resource use in a black, low-income community.

This descriptive study examined factors that influence use of poison-prevention measures and poison control center resources in a black, low-income, inner-city community. Convenience sampling was used to recruit 32 mothers of children under age 10 years at two federally funded health centers and two community food pantries. Participants were interviewed using a semistructured interview schedule. Data were analyzed qualitatively, with the results indicating that the majority of mothers had a considerable degree of awareness regarding poisoning susceptibility, severity, and prevention. However, few had access to or had used the poison control center's telephone number. Only 56% had received direct information regarding poisoning, with recall tending to be more accurate when information was obtained outside of the prenatal and postpartum settings. Lack of awareness of poisoning management and poison control center resources was most frequently cited as a barrier. Although this study was limited to one community, it indicates a possible need to distribute culturally acceptable poisoning information and frequent reinforcement for families with small children.


Health education and the immigrant Haitian mother: cultural insights for community health nurses.

Lack of information about health education from the perspective of immigrants was the basis of a descriptive survey of 30 Haitian mothers in southeast Florida. Subjects were interviewed regarding the value of health education received while seeking preventive health care for infants and preschool children in community health settings, their access to other sources of health education, and their perceptions of what community health care providers could do to assist them in improving child health. Ninety-seven percent took children for well-child care to medical facilities, and 66% received health education during the visits. Seventy percent had access to health-education programs through clinics or the media. Impediments to effective health education were lack of providers who speak Haitian Creole, need for more nurses, and long clinic waiting periods. Nurses were considered the best persons to do health teaching; radio and clinic lectures were the preferred media. Teaching was valuable if it was understandable and practical, reinforced parenting abilities, and allowed time for questions. Results are related to socioeconomic and political factors, traditional Haitian health culture, and cultural views of the cognitive development in children. Culture-specific strategies related to the modes and foci of health education are discussed.


Home care during the aftermath of Hurricane Hugo.

During the course of field observations for an ethnographic study of home care nurses' job stress, Hurricane Hugo struck the community, causing extensive damage. The nurses' office building was heavily damaged by wind and water, and their office was not habitable for almost a week. The author had observed the nurses' work practices over 10 weeks before the hurricane. In the aftermath of the storm, the nurses were simultaneously disaster victims and caregivers for other victims. They experienced grief, anger, and frustration about their losses, as well as conflict between their family- and work-related responsibilities. Their experiences and behaviors were consistent with those described in prior disaster research literature, lending further support to the earlier studies. A major asset for these nurses was their open, supportive work environment. They were able to accept and affirm one another's negative feelings and to provide support to each other as they dealt with their losses.


Acute neurobehavioural toxicity of trichothecene T-2 toxin in the rat.

The acute effects of single oral doses, 0.4 and 2.0 mg/kg, of trichothecene T-2 mycotoxin on behaviour, motor performance and nociception were studied in male Wistar rats. Both doses are sublethal and did not cause overt acute signs of intoxication. In the open field test, 2.0 mg/kg of T-2 toxin increased motionlessness and decreased sniffing (P less than 0.05) 4 hr after the administration. The higher dose shortened step-through latencies in the test trial of the 24-hr passive avoidance test (two-way shuttle box). The exponential data analysis showed that, in those rats that did not learn to avoid the dark (unsafe) compartment of the box, the retention after 2.0 mg/kg of T-2 toxin was only 25% of that in controls (P less than 0.001). T-2 toxin had no effect on motor coordination in the rotarod test and in the bridge walking test 7-8 hr after administration. T-2 toxin had no effect on nociception in the hot place test 8.5 hr after administration. The results suggest that T-2 toxin has some inactivating effects on behaviour of rats, and it seems to cause an impairment in the passive avoidance test at dose 2.0 mg/kg.


Adipose tissue distribution and chemical structure of basic lipophilic drugs: desipramine, N-acetyl desipramine, and haloperidol.

Single-dose intravenous injections of desipramine to rats resulted in a distribution pattern typical of basic lipophilic drugs, i.e., highest concentrations in lung and lowest in adipose tissue and plasma. In contrast, after N-acetyldesipramine, a non-basic analogue of desipramine with comparable lipophilicity, concentrations of this drug in adipose tissue were much higher than in lean tissue or plasma as a result of redistribution into the former and rapid disappearance from the latter tissue. N-Acetyldesipramine had much lower plasma and tissue half-lives than desipramine, but at the same time a much higher adipose/plasma concentration ratio and adipose storage index. Chronic administration of the basic lipophilic drug, haloperidol, to rats in their diet over 21 days resulted in a steady-state distribution pattern with highest concentrations in lung and lowest concentrations without accumulation in adipose tissue. This study provides additional evidence for the influence of basic groups on the distribution of lipophilic drugs. Thus, basic lipophilic drugs do not undergo redistribution into adipose tissues, possibly because of a competition by stronger binding to lean tissue as a result of lysosomotropism.


Antinociceptive effects and central nervous system depression caused by oxycodone and morphine in rats.

Antinociception and central nervous system depression (CNSD) caused by intraperitoneal, intrathecal and subcutaneous administration of oxycodone or morphine were studied in a randomized and blind, saline controlled study in rats. Antinociception was assessed with the tail-flick and hot plate tests. CNSD was assessed by testing the corneal, placing and righting reflexes and with a 4-point catalepsy score. Intraperitoneally and subcutaneously administered oxycodone and morphine were given in doses of 2.5-10 and 5-20 mg kg-1 respectively. The intrathecal doses were 12.5 micrograms and 100 micrograms of oxycodone and 6.25 micrograms and 50 micrograms of morphine. In both nociceptive tests subcutaneously and intraperitoneally administered oxycodone was 2-4 times more potent than morphine, while intrathecal morphine was over 14 times more potent. CNSD was more profound with oxycodone than with morphine after intraperitoneal and subcutaneous administration, but was not observed after intratechal administration of either drug. Differences in opioid receptor affinities, liposolubilities and metabolism are discussed as possible explanations.


Serotonin receptors in the brain of rats treated chronically with imipramine or RU24969: support for the 5-HT1B receptor being a 5-HT autoreceptor.

Rats were treated by intraperitoneal injection for four weeks with either RU24969, a 5-HT1B and 5-HT1A agonist or imipramine, a 5-HT uptake inhibitor. Pre- and postsynaptic 5-HT receptors were measured to compare the effect of direct or indirect stimulation of the 5-HT autoreceptor (5-HT1B receptor). The 5-HT transport protein (5-HT uptake site), labelled with [3H]paroxetine, was unaffected after treatment with either one of the drugs. The density of 5-HT2 receptors, labelled with [3H]ketanserin, we found increased after treatment with RU24969 (Bmax = 161 fmol/mg protein) and decreased after treatment with imipramine (Bmax = 109 fmol/mg protein) as compared with control rats (Bmax = 134 fmol/mg protein). The 5-HT1B receptor was found decreased both by the imipramine treatment (Bmax = 106 fmol/mg protein) and the treatment with RU24969 (Bmax = 105 fmol/mg protein), compared with control rats (Bmax = 130 fmol/mg protein). The 5-HT1A receptor was found to be decreased after treatment with RU24969 (control: Bmax = 62 fmol/mg protein; RU24969-treated: 49 fmol/mg protein), but unchanged after treatment with imipramine (Bmax = 58 fmol/mg protein). These results correspond to what could be expected, if the 5-HT1B receptor is the 5-HT autoreceptor.


Interactions and comparative effects of zopiclone, diazepam and lorazepam on psychomotor performance and on elimination pharmacokinetics in healthy volunteers.

A randomised, placebo-controlled, double blind single-dose cross-over study was arranged to investigate possible interactions between zopiclone (7.5 mg) and two widely used benzodiazepine (BZD) anxiolytics diazepam (5 mg) and lorazepam (1 mg) during the elimination phase of drugs. Psychomotor performance was tested before and 1, 6, 8, 12 and 24 hr after the drug administration. Simultaneously, blood samples were drawn for determination of plasma drug concentrations. The elimination of each compound was not altered by coadministration of other drugs. As expected, one hour after drug ingestion, psychomotor performance was impaired. The coadministration of drugs increased the effect. During the elimination phase, 6 and 8 hr after the drug intake, only zopiclone and lorazepam in combination slightly impaired performance as compared with the pretreatment levels, but there was no difference as compared with placebo. Adverse events after active treatments were not significantly different from those after placebo. At the recommended dose of 7.5 mg, zopiclone does not alter the elimination pharmacokinetics of the BZD anxiolytics diazepam (5mg) and lorazepam (1 mg), and neither is the elimination of zopiclone affected by these BZDs. Due to the rapid elimination of zopiclone, the increase in sedation seen after concurrent administration with BZDs is of short duration.


Comparative study of cisplatin and carboplatin on pharmacokinetics, nephrotoxicity and effect on renal nuclear DNA synthesis in rats.

To clarify the difference in nephrotoxicity between cisplatin and carboplatin, the pharmacokinetics of platinum, renal function and nuclear DNA synthesis in renal cortical and outer medullary cells were studied in rats which had received cisplatin or carboplatin. Male Sprague-Dawley rats were given either cisplatin or carboplatin intravenously at an equi-toxic dose (LD10 or LD50) and were killed at various times within 7 days after the injection. Cisplatin bound to plasma proteins more avidly than carboplatin. Much more platinum was detectable in the renal nuclei after cisplatin injection than after carboplatin injection. BUN and serum creatinine levels in the rats treated with 8.5 mg/kg of cisplatin were significantly higher than in those treated with 100 mg/kg of carboplatin. Cisplatin markedly suppressed the renal nuclear DNA synthesis both in vivo and in vitro, when compared with carboplatin. It is concluded that the differences in nephrotoxicity between cisplatin and carboplatin are related to their different inhibitory effects on nuclear DNA synthesis in the renal cells.


Effects of acute lethal cyanide intoxication on central dopaminergic pathways.

In rats treated with sodium cyanide (NaCN), 20 mg/kg intraperitoneally, the striatal dopamine (DA) level was decreased within 60 sec. compared to controls injected with NaCl 0.9%. Treatment with NaCN also increased the naturally occurring L-DOPA in the striatum, but not in the other brain regions studied. Decreased DA levels but increased L-DOPA accumulation were also seen in cyanide-treated animals after inhibition of neuronal L-aromatic amino decarboxylase. In rats given a non-lethal dose of NaCN, 2.5 mg/kg intraperitoneally, 30 min. before sacrifice and L-DOPA, 100 mg/kg intraperitoneally, 25 min. before sacrifice, regional L-DOPA levels were not significantly changed, but the striatal DA levels were diminished compared to controls. Decreased DA levels might indicate that cyanide inhibits the synthesis of brain DA. However, both increased L-DOPA and increased accumulation of L-DOPA after neuronal decarboxylase were observed after cyanide. Furthermore, we have earlier reported that lethal doses of NaCN decreased the DA metabolite HVA in the striatum but did not significantly change the oxidatively deaminated metabolite of DA, DOPAC. Inhibition of L-aromatic amino acid decarboxylase appears to play a minor role in causing decreased striatal DA levels. However, our findings might be compatible with cyanide-produced inhibition of the energy-demanding granular uptake and/or release of DA.


Cathinone, a natural amphetamine.

Cathinone is an alkaloid that has been discovered some fifteen years ago in the leaves of the khat bush. This plant grows in East Africa and in southern Arabia, and the inhabitants of these regions frequently chew khat because of its stimulating properties. Cathinone, which is S(-)-alpha-aminopropiophenone, was soon found to have a pharmacological profile closely resembling that of amphetamine; indeed, in a wide variety of in vitro and in vivo experiments it was demonstrated that cathinone shares the action of amphetamine on CNS as well as its sympathomimetic effects; thus, for example, drug-conditioned animals will not distinguish between cathinone and amphetamine. These various observations were confirmed by a clinical experiment showing that cathinone also in humans produces amphetamine-like objective and subjective effects. Finally, it was demonstrated that cathinone operates through the same mechanism as amphetamine, i.e. it acts by releasing catecholamines from presynaptic storage sites. Thus, much experimental evidence indicates that cathinone is the main psychoactive constituent of the khat leaf and that, in fact, this alkaloid is a natural amphetamine.


Age, hypertension and hypercholesterolaemia alter endothelium-dependent vascular regulation.

As a source of several vasoactive factors, the endothelium takes part in the regulation of vascular tone. The most important endothelium-derived vasoactive substances are nitric oxide, prostacyclin, endothelin-1 and contracting factors requiring the activity of cyclooxygenase. The endothelium is an obvious target organ of cardiovascular risk factors. Accordingly, functional alterations do occur with aging, hypertension and hypercholesterolaemia. All three conditions are associated with a decreased basal and simulated release of endothelium-derived nitric oxide. On the other hand, the release of endothelin-1 appears to increase with age, while the sensitivity to the peptide markedly decreases under the same conditions. In the spontaneously hypertensive rat, acetylcholine and stretch evoke the release of a cyclooxygenase-dependent endothelium-derived contracting factor, most likely prostaglandin H2. The circulating levels of endothelin-1 on the other hand are not increased in experimental and human hypertension. In the porcine coronary circulation, oxidized low-density lipoproteins selectively reduced endothelium-dependent relaxations to aggregating platelets, serotonin and thrombin which are mediated by nitric oxide. The alterations of endothelial function occurring with aging, hypertension and hypercholesterolaemia may have important clinical implications for the pathogenesis of cardiovascular disease.


Proposed guidelines for diagnosis of chromosome mosaicism in amniocytes based on data derived from chromosome mosaicism and pseudomosaicism studies.

Currently, accepted protocol which has been developed at the Prenatal Diagnosis Laboratory of New York City (PDL) requires that when a chromosome abnormality is found in one or more cells in one flask, another 20-40 cells must be examined from one or two additional flasks. Chromosome mosaicism is diagnosed only when an identical abnormality is detected in cells from two or more flasks. In a recent PDL series of 12,000 cases studied according to this protocol, we diagnosed 801 cases (6.68 per cent) of single-cell pseudomosaicism (SCPM), 126 cases (1.05 per cent) of multiple-cell pseudomosaicism (MCPM), and 24 cases (0.2 per cent) of true mosaicism. Pseudomosaicism (PM) involving a structural abnormality was a frequent finding (2/3 of SCPM and 3/5 of MCPM), with an unbalanced structural abnormality in 55 per cent of SCPM and 24 per cent of MCPM. We also reviewed all true mosaic cases (a total of 50) diagnosed in the first 22,000 PDL cases. Of these 50 cases, 23 were sex chromosome mosaics and 27 had autosomal mosaicism; 48 cases had numerical abnormalities and two had structural abnormalities. Twenty-five cases of mosaicism were diagnosed in the first 20 cells from two flasks, i.e., without additional work-up, whereas the other 25 cases required extensive work-up to establish a diagnosis (12 needed additional cell counts from the initial two culture flasks; 13 required harvesting a third flask for cell analysis). Our data plus review of other available data led us to conclude that rigorous efforts to diagnose true mosaicism have little impact in many instances, and therefore are not cost-effective. On the basis of all available data, a work-up for potential mosaicism involving a sex chromosome aneuploidy or structural abnormality should have less priority than a work-up for a common viable autosomal trisomy. We recommend revised guidelines for dealing with (1) a numerical versus a structural abnormality and (2) an autosomal versus a sex chromosome numerical aneuploidy. Emphasis should be placed on autosomes known to be associated with phenotypic abnormalities. These new guidelines, which cover both flask and in situ methods, should result in more effective prenatal cytogenetic diagnosis and reduced patient anxiety.


Transvaginal sonography-detection of findings suggestive of fetal chromosomal anomalies in the first and early second trimesters.

Over a 4-year period, 14 dyskaryotic fetuses were diagnosed by amniocentesis, performed after early detection of malformations using transvaginal sonography (TVS). These 14 dyskaryotic fetuses were detected out of 4878 sonographic screenings performed by TVS between 9 and 16 weeks' gestation. Twenty-eight per cent of the referrals were at high risk and 72 per cent were at low risk for fetal malformations. Two hundred and twenty-nine fetuses (4.7 per cent) of the screened population had 265 anomalies, 39 per cent of them being transient. In 7 of the 14 dyskaryotic fetuses (50 per cent), the sonographically detected anomalies were transient, being undetected by follow-up sonographic screenings at later gestational ages (greater than or equal to 18 weeks). Postponing the first sonographic scan aimed at malformation detection to a later gestational age may lead to transient anomalies and their associated dyskaryosis being missed.


First trimester amniocentesis between the seventh and 13th weeks: evaluation of the earliest possible genetic diagnosis.

Amniocentesis performed at the 12th week and later gives reliable results. The procedure can be performed using regimens developed for mid-trimester amniotic fluid (AF) cells. Extension to the 10th-11th week is, in principle, feasible. However, the high cytogenetic failure rate is a difficulty and despite a high clone count, the culture time is prolonged. The problem of the relatively high loss of AF could be overcome by cell filtration techniques and replacement of the fluid. Because of the short turnover rate of the AF, this may be unnecessary or replacement with an isotonic solution may be sufficient. (Pseudo)mosaicism appears to occur more frequently in early than in late amniocentesis. As yet, data are too sparse to allow a comparison with chorionic villus sampling. There are no reliable follow-up data from which to estimate the abortion rate and the number of embryonic malformations.


Mutation analysis for prenatal diagnosis and heterozygote detection of Gaucher disease type III (Norrbottnian type).

A single base substitution in exon 10 of the glucocerebrosidase gene was detected in families affected by Gaucher disease (GD) type III. This mutation, which results in the substitution of proline for leucine in position 444 of glucocerebrosidase, has been shown to result in type III GD in a Swedish population. Three fetuses at risk for GD type III were diagnosed as homozygous for the mutation and the pregnancies were terminated. In a fourth pregnancy, one parent was excluded as being a carrier and the risk of having a child affected by GD was ignored. Direct analysis of common mutations causal to GD is now available and improves prenatal diagnosis in families where the molecular defect has been characterized.


First-trimester amniotic fluid and extraembryonic coelomic fluid acetylcholinesterase electrophoresis.

Acetylcholinesterase (AChE) gel electrophoresis was performed on samples of amniotic fluid and extraembryonic coelomic fluid obtained by high resolution transvaginal ultrasound-guided amniocentesis from 38 women between 8 and 12 weeks of pregnancy. AChE was positive in 33 per cent (12/36) of the amniotic fluid samples; the percentage of positive results decreased as gestation advanced. AChE was positive in 32 per cent (9/28) of the extraembryonic coelomic fluid samples. In 81 per cent (21/26) of matched samples, the AChE results were identical in the two fluids. Amniotic fluid and extraembryonic coelomic fluid AChE electrophoresis cannot be used to diagnose neural tube defects prior to 12 weeks of gestation.


Cytogenetic experience in prenatal fra(X) detection on amniotic fluid cultures.

Since 1987, we have had experience with 13 prenatal diagnoses of 11 women at risk for the fragile X syndrome by cytogenetic studies on amniotic fluid cultures. The induction method included TC 199 medium and methotrexate. Results were obtained in all cases. Ten were males and three were prenatally diagnosed as being affected. Three were females and none of them was fra(X)-positive. Results were confirmed in 10/13 cases. In these cases, we had neither false-positive nor false-negative results.


Factors regulating and modifying dental root resorption.

A comparison is made between the resorption of bone and the resorption of the mineralized tissues of teeth. The structure and function of osteoclasts are described well as the factors that regulate their activity. The cells resorbing the dental mineralized tissues are of the same cell type as osteoclasts. The dental tissues are covered by cementoblasts or odontoblasts which differ from the osteoblasts in that they do not respond to hormones and cytokines that stimulate bone resorption. Root resorption therefore seem to require damage of the cementoblastic layer in combination with necrosis or inflammation or replacement of the cementoblastic layer by osteoblasts. The root resorption that occurs at the shedding of the primary teeth is induced in a different way possibly by substance(s) from the reduced enamel epithelium. There seems to be no systematic study on the frequency and extension of root resorption in association with inflammatory or neoplastic conditions. It is suggested that dentigerous cysts and some epithelial tumors induce root resorption in the same way as the erupting tooth. The mechanisms by which some other tumors or tumor-like conditions cause root resorption are essentially unknown.


Relation of dentin sensitivity to histological changes in dog teeth with exposed and stimulated dentin.

The effect of chronic exposure of dentin to the sensitivity of intradental nerves was studied in dogs. The dentin of canine and incisor teeth was exposed one week prior to the experiments in which 34 single fiber units dissected from the inferior alveolar nerve were recorded. In the teeth with acutely bared dentin 36 nerve fibers were tested. SEM of the chronically exposed dentin showed that practically no tubule apertures could be found since the surface was covered with bacteria and oral debris. This coating had to be removed by drilling and acid etching before any responses could be evoked. When compared to the teeth with acutely exposed dentin, the sensitivity of the fibers responding to drilling, probing, osmotic stimulation, and air blasts applied to the dentin was weakened in the chronic cases, in the sense that fewer units of those tested responded. However, cold evoked nerve activity only in some chronically exposed teeth, suggesting sensitization of the nerves. TEM revealed electron-dense substance in the dentinal tubules of the chronic teeth. Some of the material was evidently cellular remnants aspirated from the pulp and some of it, staining more faintly, could be extravasated plasma proteins. In the acute cases the tubules were emptier. Light microscopy showed histological injuries in the pulp-dentin border. It is concluded that the decrease in the responsiveness of the pulp nerve fibers in the chronic cases was due to the changes in the dentin.


Effect of serotonin (5-HT) and calcitonin gene-related peptide (CGRP) on the function of intradental nerves in the dog.

Several inflammatory mediators including serotonin (5-HT) have been indicated to play a role in the sensitization of intradental nerves. In the present investigation, using the single fibre recording technique, the effect of locally applied 5-HT (1 mg/ml) and calcitonin gene-related peptide (rat CGRP 2 micrograms/microliters) on the function of intradental nerves in the dog was studied. The effect of these substances on the pulpal blood flow was also investigated to check their effective diffusion into the dental pulp. 5-HT induced a low-frequency background firing in 11 out of 30 nerve fibres. The number of fibres responding to probing, air blast and osmotic stimulation was increased significantly after 5-HT application. Three fibres responded to cold stimulation after 5-HT application; no responses were induced before. After CGRP application, a continuous low-frequency firing was induced only in 1 fibre out of 11 and 1 fibre which before did not respond to osmotic stimulation gave responses to saturated glucose. The responses to probing and air blasts were qualitatively unchanged. Local application of either of the substances induced a change in pulpal blood flow. It is suggested that while 5-HT is able to sensitize intradental nerves to various hydrodynamic stimuli, CGRP seems to be less effective. Pulpal inflammation with the release of inflammatory mediators may significantly affect the degree of dentine sensitivity.


Effect of aging and caries on dentin permeability.

Extracted human teeth were collected from young (20-28 yrs) versus old (45-69 yrs) patients. The teeth were divided into carious and noncarious groups. Slabs were created from the mid-coronal occlusal dentin. Carious lesions were excavated and the smear layers on both normal and excavated carious dentin were removed with 37% phosphoric acid (1 min). The permeability (hydraulic conductance) of old normal dentin was only 20% of that obtained in young normal dentin but all of the specimens were permeable. Young carious dentin was only 14% as permeable as young normal dentin and only 1 out of 7 specimens was not permeable. All 7 specimens of old carious dentin were impermeable. Scanning electron microscopy of old and carious dentin exhibited far more intratubular crystals than normal dentin, providing a structural basis for the functional observation.


Neurophysiological mechanisms of dentin hypersensitivity.

In hypersensitive teeth pain is typically induced by cold and hot fluids or foods brought to contact with the sensitive dentin or by osmotic and mechanical stimuli. The results of animal experiments indicate that intradental A-type nerve fibres are responsible for the sensitivity of dentin. They are most probably activated by the hydrodynamic mechanism. Thus, their activation is to a great extent dependent on the condition of dentin with either open or blocked dentinal tubules. Blocking of the tubules effectively prevents the nerve activation. Correspondingly, in human experiments, the condition of the dentinal tubules greatly affects dentin sensitivity. In clinical studies significantly more open tubules are found in sensitive compared to non-sensitive areas. However, hypersensitivity may sometimes persist despite of effective blocking of the tubules. This may indicate that some other mechanisms may operate in the nerve activation instead of, or in addition to the hydrodynamic one. Inflammation may sensitize the nerve endings to such an extent that smaller fluid shifts would be sufficient for nerve activation or, for example, thermal stimulation may activate the nerves by a direct effect. On the other hand, spontaneously occurring changes in the exposed dentin, which in many cases seem to block the tubules may reduce the responses to hydrodynamic stimulation and, thus, have an opposite effect on dentin sensitivity. The results of animal experiments indicate that functional changes of this kind may occur. These results also indicate that real dentin hypersensitivity can develop as a result of inflammation induced sensitization of the nerves in the pulp-dentin border in teeth with open dentinal tubules.(ABSTRACT TRUNCATED AT 250 WORDS)


Factors influencing the occurrence of pain in carious teeth.

The mechanisms by which pain develops in carious teeth are poorly understood. The variability of dentin and pulp responses to carious attack is probably the cause for the variations in the pain symptoms presented by patients. This article is a review of the available data regarding the changes that dentin and pulp undergo in carious teeth. Such changes are discussed in relation to their possible influence on intradental sensory nerve excitability. Special emphasis is given to the various bacterial metabolites produced and accumulated in carious dentin and their ability to modulate pain symptoms from carious teeth.


Effects of CO2 laser irradiation on pulpal blood flow.

CO2 laser may be beneficially applied to teeth in preventive and restorative dentistry, but its physiopathologic effects on the dental pulp have not been reported. To address the dynamic pulpal changes induced by CO2 laser the purpose of this study was to examine such changes in pulpal microcirculation. The enamel surfaces of 4 cat canines were irradiated by CO2 laser beam, delivered by either a handpiece or microslad with a focal spot diameter of 0.21mm and 0.33mm, respectively. Exposure powers of 2.6-20 W were used for durations of 0.05-0.2 sec, resulting in energy density range of 304-1440 J/cm2. Non-invasive measurement of pulpal blood flow (PBF) by a laser Doppler flowmeter was maintained continuously before and following CO2 laser irradiation. CO2 laser irradiation resulted in an immediate increase in PBF, which subsided after 2-3 min. Large pulps responded with a significantly higher PBF increase than small pulps. These results confirm that CO2 laser irradiation of the tooth surface has a thermal effect on the pulp, which is moderated by the insulating capability of dentin. It appears that the associated thermal damage is not extensive when laser exposure parameters are such as used herein.


Changes in expression of alpha 1 type 1 collagen and osteocalcin mRNA in osteoblasts and odontoblasts at different stages of maturity as shown by in situ hybridization.

We investigated whether the expressed phenotype of osteoblasts and odontoblasts is changing with increasing maturity of the cells. Thus we determined, using in situ hybridization techniques, whether the expression of mRNA's for osteocalcin and the alpha 1 type 1 collagen chain was different in newly developed and more mature cuboidal osteoblasts of the primary and secondary spongiosa of radii of 8 day old rats, in mature cuboidal and older flat osteoblasts in the metatarsals of pig embryos, and in apical and coronal odontoblasts of the developing unerupted molars of pig embryos. The results indicate that newly differentiated osteoblasts in the primary spongiosa of the 8 day rat radius contained approximately the same amount of type 1 collagen message as more mature osteoblasts in the secondary spongiosa. Osteocalcin mRNA, on the other hand, was undetectable in the newly differentiated osteoblasts but clearly detectable in the mature osteoblasts of the secondary spongiosa. When we compared expression of osteocalcin and collagen type 1 mRNA in mature cuboidal and older flat osteoblasts, we found that the amount of osteocalcin mRNA relative to collagen type 1 mRNA was higher in flat osteoblasts than in cuboidal osteoblasts. In odontoblasts, however, the steady state level of collagen type 1 mRNA was higher in the older coronal odontoblasts, and the level of osteocalcin message lower, when compared to the younger apical odontoblasts. The results indicate that relative levels of osteocalcin and collagen mRNA in osteoblasts and odontoblasts vary depending on the stage in their secretory lifetime. This heterogeneity of the osteoblast and odontoblast population suggests that the composition of the matrix produced by these cells also differs.


Repair dentinogenesis following transplantation into normal and germ-free animals.

The purpose of this study was to investigate the dentinogenesis of dental pulp tissue following transplantation and during regeneration in normal and germ free animals, as well as in vitro experiments. (1) Partial and complete exposure of dental pulp in germ free rats by removing the enamel and dentin of molars. (2) The central portion of rat incisor which consisted of pulp and pulp chamber were autografted into various tissues. (3) Explants of rat pulp tissue were cultured on dentin matrix. (4) Resin bonding agent, 4-META/MMA-TBB-O (Superbond), was placed directly on surgically-exposed dental pulp. (1) Dentin bridge formation was recognized at 5 days after operation in germ free rat. (2) The cut surface of the transplant exhibited dentin bridge at 7 days after implantation, and the thickness of the newly formed dentin increased gradually thereafter up to 30 days. (3) Cultured pulp cells had high alkaline phosphatase activity and bone- or dentin-like hard tissue was synthesized on the dentin matrix in vitro. (4) Dentin bridge formation was evident on the surgically-exposed dental pulp even after application of Superbond. From these results, it is suggested that pulp tissue has a high activity of dentinogenesis both in vivo and in vitro and 3 days is enough for pulp cells to express the odontoblast phenotype when inflammatory factors are not present.


Dentin phosphoprotein in dentin development: implications in dentinogenesis imperfecta.

Dentin phosphoprotein (DPP, phosphophoryn) is the major non-collagenous protein component of the dentin extracellular matrix. This highly acidic phosphorylated protein is solely expressed by ectomesenchymal-derived odontoblast cells of the tooth organ. Previous biochemical studies have suggested the absence of this protein associated with the human genetic disease dentinogenesis imperfecta (DGI) Types I and II. However, due to the normal degradation of human DPP during dentin maturation, it has not been possible to establish if these reported differences were due to changes in DPP expression or secondary degradation rates in DGI affected versus normal teeth. Recently, we have taken both a molecular and biochemical approach to address this problem. Molecular studies have utilized genetic linkage studies performed on several multi-generation informative DGI kindreds. These studies have determined linkage between DGI Types II and III and two markers localized to the long arm of human chromosome 4 in the region 4q11-4q21. The strategy used in our study was to map the DPP gene locus to the long arm of human chromosome 4, in the same region as DGI, using a DPP oligonucleotide probe and somatic hybrid cell lines. The results indicate DPP is not localized to any region of human chromosome 4. Our data indicates that a mutation within the DPP gene locus is not associated with DGI Types II or III. This data is supported by the identification of human DPP (95 kDa) within the dentin extracellular matrix of molars isolated from an affected DGI type II patient using a mouse anti-DPP antibody. However, this does not exclude the possibility that enzymes associated with DPP post-translational modifications (ie. phosphorylation or degradation) might be responsible for this genetic disease.


Molecular control of dentinogenesis: a reaction.

This paper represents an invited reaction to three papers presented at the International Conference on Pathobiology of the Dentin/Pulp Complex, June, 1991. Repair dentinogenesis following transplantation into normal and germs free animals are correlated with results elucidating the expression of dentin phosphoproteins, collagen, and osteocalcin. The importance of transcription and translation controls of dentin matrix components are discussed and reviewed. In addition, possible implications of a molecular chaperone protein, Hsp47, in controlling dentinogenesis is introduced. Future research directions are developed and include: (a) identification of odontoblast precursors; (b) delineation of markers for odontoblasts at varying degrees of differentiation; (c) characterization of environmental conditions leading to odontoblast differentiation; (d) determination of the nature of repair and regenerated tissues; (e) elucidation of transcription and translation control factors, and (f) mapping the human genome for dentin matrix constituents.


Smear layer: overview of structure and function.

Smear layers are created on hard tissues whenever they are cut with hand or rotary instruments. This thin (1-2 microns) layer of denatured cutting debris is very tenacious and, in fact, is often the surface to which restorative materials are luted. The solubility characteristics, chemical reactivity and the structure-function relationships of this layer have not yet been well-defined. During creation of the smear layer, cutting debris is forced variable distances into dentinal tubules. These so-called smear plugs, together with the smear layer decrease dentin permeability, dentin sensitivity and surface wetness. Bonding adhesive resins to smear layers appears to limit the theoretical bond strength unless the smear layers are loosened or partially removed. Future research in this area will include the use of surface analytical techniques such as Auger electron spectroscopy and ESCA. These techniques are required because of the thinness of the smear layer. It is clear that the nature of this critical interface between dental materials and cut hard tissues remains largely unknown. This field will provide fertile ground for future research.


Smear layer--materials surface.

SEM and TEM photomicrographs were presented of the smear layer and several dentin-adhesive interfaces. It was shown that as the wetting and penetration of the dentin adhesive increased, the shear bond strength also increased. Three categories of dentin adhesives were presented. Category one included Scotchbond, Dentin Adhesit and Gluma, with shear bond strength values between 5 and 7 MPa; the second category, dentin adhesives based on Dr. Bowen's research, included Tenure and Mirage Bond, with shear bond strengths between 8 and 14 MPa; the third category included Superbond and Scotchbond 2, with shear bond strength values up to 20 MPa. Failures occurred at the interface or in the resin adhesive for materials in categories one and two; failures occurred through the dentin or composite for materials in category three.


Clinical aspects of dentine hypersensitivity.

Dentine hypersensitivity is a common painful condition about which relatively little is known. A review of the literature reveals that most research has been concerned with the clinical assessment of therapeutic agents. However, even here there is little information concerning the actual mode of action of such agents. Many clinical aspects of the condition also appear anecdotal at best and there is always a need to consider a differential diagnosis to exclude other causes of dentinal pain. Detailed prevalence figures are not available for dentine hypersensitivity as it affects different groups, although age and possibly gender differences are apparent. Additionally, the condition shows predilections for certain oral sites which may be of aetiological relevance. Consistent with the hydrodynamic theory hypersensitivity lesions reveal large numbers of widened dentinal tubules at the surface and patent to the pulp. The use of dentine replica techniques could prove useful in objectively studying the condition and monitoring treatments. It is apparent that in clinical management little attention has been paid to factors which expose dentine and open tubules. Without consideration of aetiological factors the management of Dentine Hypersensitivity may be compromised.


An ultrastructural and autoradiographic analysis of primary and replacement odontoblasts following cavity preparation and wound healing in the rat molar.

Numerous studies using various animal and human models have reported changes in the morphology and metabolic activity of primary odontoblasts in the mature tooth pulp after perturbations of the tooth including cavity preparation and restoration, pulpal exposures and pulp capping with various capping agents. The first part of this study investigated changes in primary and replacement odontoblast activity after cavity preparation or pulpal exposure. Two groups of rats were used in this investigation. One group of rats had Class V cavities prepared to the DEJ of the first maxillary molars. These rats were immediately injected with 3H-proline and killed 15, 30 or 60 minutes later. Rats killed at day 1, 3, 5, 7, 10 or 14 were injected one hour prior to sacrifice. The second group of rats each had a pulp exposure that was capped with a calcium hydroxide containing material and restored with a composite resin. Rats were sacrificed as previously described. Tissue was processed routinely for ultrastructural analysis and E.M. autoradiography. The second part of this study consisted of an injection of 125I-fibrinogen one hour prior to a class V cavity preparation 1/2 the distance through dentin thickness. Rats were sacrificed at 5, 10, 15 and 30 minutes postsurgery. Differences in the location and distribution of the reduced silver halide grains were recorded as well as differences in the amount and distribution of the various organelles measured between primary and replacement odontoblasts. The results of this study suggests that primary and replacement odontoblasts were morphologically and physiologically dissimilar at the time periods tested in this study. 125I-fibrinogen was demonstrated within the dentinal tubules and in the floor of the cavity preparation as early as 5 minutes after completion of the cavity preparation. The preliminary results of the 125I-fibrinogen suggest that operative trauma can effect very rapid changes to the dental pulp leading to leakage of plasma proteins from the circulation, between odontoblasts, out of the tubules to the cut dentin surface.


Odontoblast response under carious lesions.

The local regulation of odontoblast response to caries is viewed through initiation and elaboration of sclerotic as well as reparative dentin. Dentin tissue represents a multiple source of potent environment factors when teeth are affected by the demineralization phases of carious process. Some of them have already been identified in sound tissue (matrix glycoproteins, proteoglycans, growth factors, Bone Morphogenetic Protein) and may act on the cell through membrane receptors. Thus, the amplification in collagen synthesis and alkaline phosphatase activity previously observed during sclerotic dentin deposition can be related to the interaction between matrix signals and cell receptors such as the 165 kDa protein shown only by odontoblasts under the affected zone. Similarly, under established lesions generating cell death, the specific matrix made of odontoblasts debris and damage tissues, probably rich in active molecules, may trigger pulp cells to elaborate a cartilage-like layer (identified by type II and XI collagen) followed by odontoblast-like cells to give rise to abnormal tubular dentin. Here, odontoblast response is identical to bone-cells response to injury. What remains to be elucidated concern: The nature of signals found in carious dentin (matrix components, growth factors, bacterial products). The nature and regulation of expression of cell membrane receptors during tooth repair. How the odontoblast produces specific responses to each of these signaling molecules will be the focus of important new investigations.


Preliminary studies on pulp capping with demineralized dentin.

The use of osteoinductive demineralized dentin matrix in the repair of vital pulp exposures was examined. The pulps of the maxillary first molars of adult male Long Evans rats were exposed and capped with either demineralized dentin particles or guanidinium extracted demineralized dentin particles; then covered with a glass ionomer cement restoration. The animals were sacrificed after two weeks and the maxillae were dissected free, fixed in formaldehyde and demineralized. Histologic examination revealed that in those cases where the protective glass ionomer restoration was intact, both groups showed some healing. There was some preliminary indication that the extent of reactive matrix formation was greater in the osteoinductive group. In both groups, odontoblast-like cells appeared to incorporate some of the dentin particles into the reparative dentin bridge. This preliminary work suggests that osteoinductive factors present in demineralized incisor dentin might be used to guide the formation of a dentin bridge in a rat model for vital pulp exposures.


Genetic marker study of dentinogenesis imperfecta.

DGI-II has been linked to the group specific component (Gc) on 4q and to interferon induced protein 10 (INP10) on 4q. We studied a three generation family with DGI-II along with a four generation DGI-II family to more precisely place DGI-II in the existing genetic map of 4q and to determine if genetic heterogeneity existed between various DGI-II families. Affected family members had brownish discoloration of the teeth, enamel fracturing and radiographic evidence of coronal and radicular pulp chamber obliteration. Thirteen polymorphic markers on 4q were studied including D4S35, D4S1, ALB, Gc, MGSA, AR, INP10, ADH3, FGFB, EGF, IL2, IF, and MNS. Gc and MNS blood group antigen typing were done using commercial SERA. Restriction fragment length polymorphism analysis using Southern blotting was done on the remaining markers. Pairwise linkage analysis was performed using the procedures of Morton. Tight linkage between DGI-II and eleven genetic markers, including Gc and EGF, was excluded. The tightest linkage with DGI-II was identified with the probe INP10 at theta = 0.0 with lod = +3.91. However, INP10 RFLP differences were detected between the families, such that DGI-II correlated with different alleles in each family. Results from this study demonstrated that DGI-II may possibly arise from more than one genetic mutation.