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Biomedical subjects

M Silverman

Publications and source records attributed to M Silverman.

At least 199 records · Page 11Linked to original sources
PubMed1991

Linkage exclusion between the autosomal dominant polycystic kidney disease locus and chromosome 16 markers in a new family.

A family segregating for autosomal dominant polycystic kidney disease (ADPKD) is reported. The clinical picture was typical for ADPKD in some family members, although others showed mild involvement. DNA from family members was probed with seven chromosome 16 single-copy DNA sequences that mapped to the telomere of the short arm of the chromosome. The most likely order of six of the probes from the telomere is palpha3'HVR.64 at the designated locus D16S85, CRI-0327 at D16S63, CRI-090 at D16S45, CRI-0129 at D16S56, CRI-0133 at D16S58, and CRI-0136 at D16S60, with the PKD1 locus for ADPKD between D16S85 and D16S63. The seventh probe 24-1 at D16S80 had not been ordered in relation to the other sequences, but PKD1 had been mapped between it and D16S85. The three probes that were informative in our family, palpha3'HVR.64, CRI-090, and CRI-0136 had been linked to the disease locus at recombination frequencies of 4% and approximately 6 and 12%, respectively. Linkage was excluded between the ADPKD locus in our family and palpha3'HVR.64 at a recombination value of up to 6%. Linkage was also excluded between CRI-090 and the disease locus at a recombination value of up to 5%. The data for linkage between CRI-0136 and the ADPKD locus in our family were inconclusive. Multipoint analysis excluded the possibility that the disease in this family lies between the flanking genetic markers that have previously been used to define the genetic interval in which the most common form of polycystic kidney disease, PKD1, lies. We have not made a positive assignment of the ADPKD mutation in this family.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosomes, Human, Pair 16↗
PubMed1991

Sequence and features of the tryptophan operon of Vibrio parahemolyticus.

The nucleotide sequence of the trp operon of the marine enteric bacterium Vibrio parahemolyticus is presented. The gene order E, G, D, C(F), B, A is identical to that of other enterics. The structural genes of the operon are preceded by a long leader region encoding a 41-residue peptide containing five tryptophan residues. The organization of the leader region suggests that transcription of the operon is subject to attenuation control. The promoter-operator region of the V. parahemolyticus trp operon is almost identical to the corresponding promoter-operator of E. coli. The similarities suggest that promoter strength and operator function are identical in the two species, and that transcription initiation is regulated by repression. The operon appears to lack the internal promoter within trpD that is common in terrestrial enteric species.

Base Sequence↗
PubMed1991

A case of insect borne tularemia above the tree line.

A case of insect borne transmission of ulceroglandular tularemia in Canada above the tree line is presented. It seems likely from the available entomological data that a mosquito was the vector in this case. Mosquito vectors may be important in inducing the high seroprevalence of antibodies to F. tularensis above the treeline. This case is presented to make clinicians aware of the possibility of tularemia in cases of insect borne ulceroglandular disease in the arctic and, the necessity of measuring tularemia agglutinins in these patients. It should be noted that isolation of this organism poses a risk to laboratory personnel, and therefore should only be attempted in a reference laboratory. Therefore the diagnosis is based upon the finding, in the appropriate clinical context, of a four-fold rise in the tularemia agglutinins, or a single convalescent titre of 1:160 or greater.

Adolescent↗
PubMed1991

A flow interruption device for measurement of airway resistance.

Unlike conventional methods, the interrupter method for measuring airway resistance is non-invasive and requires minimal patient co-operation. It can therefore be applied in critically ill patients, acute asthmatics, neonates, pre-school children, geriatric patients and unconscious patients. The method is based on transient interruption of airflow at the mouth for a brief period during which alveolar pressure equilibrates with mouth pressure. Measurement of mouth pressure is used to estimate alveolar pressure prior to interruption and the ratio of this to flow prior to interruption gives airway resistance. Using the interrupter method we have developed a portable device for measuring airway resistance which is simple to use and gives a direct instantaneous reading. Measurements of airway resistance obtained using the new device were compared with those obtained using conventional body plethysmograph methods in 43 adult patients. A close correlation was seen (r = 0.86). The two methods appear equally sensitive in detecting changes in airway resistance following bronchodilator therapy. The device has been used successfully in pre-school children unable to co-operate with conventional methods.

Adult↗
PubMed1990

Relationship between infant lung mechanics and childhood lung function in children of very low birthweight.

Twenty-seven children of very low birthweight (less than or equal to 1,500 g) whose lung function had been measured on several occasions during the first year were studied at the age of about 9 years. Fifteen of the children had received neonatal intermittent positive pressure ventilation, mostly for respiratory distress syndrome. Ten of the ventilated children were still oxygen dependent at 30 days of age. Compared to the remainder of the group, mechanically ventilated children had reduced lung compliance in early infancy and increased thoracic gas volume in the middle of their first year. These changes correlated with the level of neonatal respiratory therapy as indicated by the oxygen score. Lung compliance in early infancy, but not thoracic gas volume, correlated with forced expiratory volume at 1 second recorded at 9 years. On the other hand, reduced airway conductance showed no significant correlation with the neonatal oxygen score, but there was a strong correlation between airway conductance late in infancy and lung function at 9 years. This relationship was independent of neonatal mechanical ventilation. We conclude that perinatal factors, which may be associated with disturbed lung mechanics early in infancy, are only weak and indirect predictors of childhood lung function. Airway conductance late in infancy, determined by constitutional factors, prematurity itself or other undetermined factors, is a good predictor of airway function at 9 years.

Bronchopulmonary Dysplasia↗
PubMed1990

Nature, nurture, nutrition: interdisciplinary programs to address the prevention of malnutrition and dehydration.

Malnutrition and dehydration are common problems in nursing home patients. One explanation for this may be the large number of patients requiring feeding assistance. The Dysphagia Team at the Department of Veterans Affairs Medical Center in Miami, Florida served as the primary source in the expansion of a nutritionally supportive environment to assist in the prevention of malnutrition and dehydration in patients with feeding/swallowing disorders. "Silver Spoons," a program in which volunteers provide supervised feeding, "Happy Hour," a time each day during which an atmosphere is provided that encourages socialization and hydration, and "Second Seating," during which lunch is provided for patients who require modification of eating style, food texture, or timing are described. Analysis of the program's outcomes show it to be timely, pleasing to patients, and cost-effective.

Aged↗
PubMed1990

The role of anticholinergic antimuscarinic bronchodilator therapy in children.

In the intricate system of control of airway caliber, the cholinergic (muscarinic) sympathetic nervous system has an important role. Despite the paucity of physiologic or clinical data, it is clear that anticholinergic, antimuscarinic bronchodilator therapy is useful in the management of childhood airway disease. Ipratropium bromide is the only safe and adequately studied agent. It is effective in conjunction with beta-agonists in acute severe childhood asthma and has an important role in the management of wheezy infants and in chronic lung disease of prematurity (bronchopulmonary dysplasia).

Airway Resistance↗
PubMed1990

Survival of the cornual pregnancy in a heterotopic gestation after in vitro fertilization and embryo transfer.

We present a case of combined intrauterine and cornual (interstitial) pregnancy after IVF-ET, with survival of the infant after the cornual pregnancy. The diagnosis of this rare phenomenon is difficult; a high index of suspicion and frequently ultrasound monitoring may enable early diagnosis in other forms of heterotopic pregnancy. Although the benefits of IVF-ET far outweight the risks of ectopic pregnancy, it is imperative that physicians who care for these patients be fully aware of the possibility of such a complication in this high-risk population.

Adult↗
PubMed1990

Evaluation of nebulizers for use in neonatal ventilator circuits.

The use of nebulizers in neonatal ventilator circuits offers a new and relatively uncharted route of therapy for infants in respiratory failure. We used a model lung to investigate and compare different nebulizer types and therapeutic agents and to make practical observations. Five different nebulizers (Ultravent, Acorn, MAD2, Small Particle Aerosol Generator, and Pulmosonic) were compared for efficiency of delivery of an amino-phylline aerosol to the model lung, and the particle size of aerosol produced by them was measured. A Nebulizer Efficiency Index (NEI) was created, representing the deposition rate of the original solution as aerosol upon the model lung filter. The Acorn (2.8.10(3) ml/min) and MAD2 (2.4.10(-3) scored highest NEI. When a suspension of budesonide was nebulized, minimal amounts of drug were recovered from the filter when the nebulizer producing the smallest particle size (Ultravent) was studied, suggesting that suspensions of drugs behave differently from solutions. Significant changes need to be made to a conventional circuit when jet nebulizers are used; most of these are obviated by the use of an ultrasonic nebulizer, which also avoids the potential problem of marked cooling of the gas flow produced by jet nebulizers.

Aerosols↗
PubMed1990

Surface-induced swarmer cell differentiation of Vibrio parahaemolyticus.

Vibrio parahaemolyticus distinguishes between life in a liquid environment and life on a surface. Growth on a surface induces differentiation from a swimmer cell to a swarmer cell type. Each cell type is adapted for locomotion under different circumstances. Swimmer cells synthesize a single polar flagellum (Fla) for movement in a liquid medium, and swarmer cells produce an additional distinct flagellar system, the lateral flagella (Laf), for movement across a solid substratum, called swarming. Recognition of surfaces is necessary for swarmer cell differentiation and involves detection of physical signals peculiar to that circumstance and subsequent transduction of information to affect expression of swarmer cell genes (laf). The polar flagellum functions as a tactile sensor controlling swarmer cell differentiation by sensing forces that restrict its movement. Surface recognition also involves a second signal, i.e. nutritional limitation for iron. Studying surface-induced differentiation could reveal a novel mechanism of gene control and lead to an understanding of the processes of surface colonization by pathogens and other bacteria.

Cell Movement↗
PubMed1990

Electroconvulsive therapy in octogenarians.

Medical records of 81 older patients (65 years of age and over) who underwent electroconvulsive therapy (ECT) at a university-affiliated private geriatric hospital were reviewed to evaluate the safety and efficacy of this treatment for depression in the "young-old" (65 to 80 years) compared with the "old-old" age group (over 80 years), a group that has not yet been adequately studied. Information was obtained regarding demographics, medical and psychiatric diagnosis, medications, indications for ECT, number and laterality of treatments, outcome, and complications. Thirty-nine patients 80+ years of age (mean age, 85 +/- 3.2) were compared with 42 patients 65 to 80 years of age (mean age, 74 +/- 5.2). Statistical analysis was performed using confidence intervals of the difference in proportions of patients in each group. There were no significant differences in the demographics, number and laterality of ECT treatments, indications for ECT treatment, medical diagnosis, medications, or prior history of falls, but psychiatric diagnoses differed slightly. Patients over 80 years had significantly more cardiovascular complications and falls (95% confidence interval) and tended to have a worse ASA (American Society of Anesthesiologists) scale rating and a somewhat less successful outcome. This study confirms the role of ECT as a relatively safe and effective treatment, which may be lifesaving in selected depressed older patients. Prospective studies are needed to understand better the long-term outcome and to prevent the morbidity and mortality associated with ECT in this frail, high-risk older group.

Accidental Falls↗
PubMed1990

Chemotactic control of the two flagellar systems of Vibrio parahaemolyticus.

Vibrio parahaemolyticus synthesizes two distinct flagellar organelles, the polar flagellum (Fla), which propels the bacterium in a liquid environment (swimming), and the lateral flagella (Laf), which are responsible for movement over surfaces (swarming). Chemotactic control of each of these flagellar systems was evaluated separately by analyzing the behavioral responses of strains defective in either motility system, i.e., Fla+ Laf- (swimming only) or Fla- Laf+ (swarming only) mutants. Capillary assays, modified by using viscous solutions to measure swarming motility, were used to quantitate chemotaxis by the Fla+ Laf- or Fla- Laf+ mutants. The behavior of the mutants was very similar with respect to the attractant compounds and the concentrations which elicited responses. The effect of chemotaxis gene defects on the operation of the two flagellar systems was also examined. A locus previously shown to encode functions required for chemotactic control of the polar flagellum was cloned and mutated by transposon Tn5 insertion in Escherichia coli, and the defects in this locus, che-4 and che-5, were then transferred to the Fla+ Laf- or Fla- Laf+ strains of V. parahaemolyticus. Introduction of the che mutations into these strains prevented chemotaxis into capillary tubes and greatly diminished movement of bacteria over the surface of agar media or through semisolid media. We conclude that the two flagellar organelles, which consist of independent motor-propeller structures, are directed by a common chemosensory control system.

Chemotaxis↗
PubMed1990

How much aerosol reaches the lungs of wheezy infants and toddlers?

Using sodium cromoglycate as a non-toxic marker, we assessed the delivery of aerosol to nine wheezy infants and seven healthy adults. The drug was delivered to the infants by face mask and spacer device from a metered dose inhaler, and by face mask and nebuliser to the infants and the adults who breathed though their noses. The concentration of sodium cromoglycate was estimated in timed urine collections to find out how much of the dose was absorbed from the lung. Only 0.13% to 0.61% of the 20 mg nominal dose was detected in the urine, representing an estimated 0.3% to 1.5% deposited in the lung. Nasal filtration of aerosol could be a critical factor in reducing lung deposition.

Absorption↗
PubMed1990

Treatment of acute, episodic asthma in preschool children using intermittent high dose inhaled steroids at home.

In a double blind, controlled trial, the effect of high dose beclomethasone dipropionate (750 micrograms three times daily for five days) administered by metered dose inhaler and valved spacer, was compared with placebo, during 70 paired episodes of acute asthma in 24 preschool children. Treatment commenced at home at the first sign of an attack. Parents' blind preference for active treatment was significant. Data from 17 pairs of treatment, however, were affected by interventions such as hospital admission or oral corticosteroid treatment. These events occurred similarly in active and control periods. An intrasubject comparison was made of diary scores from the 18 pairs of episodes in which no intervention occurred in either the active or placebo treatment. Both daytime and night symptoms over the first week of the attack were significantly reduced by active treatment. Intermittent high dose inhaled beclomethasone dipropionate is beneficial in modifying the severity of acute episodic asthma in preschool children able to use a spacer device.

Acute Disease↗