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Biomedical subjects

R C Stern

Publications and source records attributed to R C Stern.

At least 37 records · Page 2Linked to original sources
PubMed1994

Efficacy of the Flutter device for airway mucus clearance in patients with cystic fibrosis.

The Flutter is a handheld device designed to facilitate clearance of mucus in hypersecretory lung disorders. Exhalation through the Flutter results in oscillations of expiratory pressure and airflow, which vibrate the airway walls (loosening mucus), decrease the collapsibility of the airways, and accelerate airflow, facilitating movement of mucus up the airways. We studied 18 patients with cystic fibrosis and mild to moderate lung disease to determine the efficacy of the Flutter in clearing mucus from the airways. The amount of sputum expectorated (measured by weight) when the Flutter was used was compared with the amount expectorated with vigorous voluntary coughing and with postural drainage (chest percussion and vibration). The amount of sputum expectorated by subjects using the Flutter was more than three times the amount expectorated with either voluntary cough or postural drainage (p < 0.001). There were no adverse effects. The Flutter is simple to use, inexpensive, and fully portable, and once the patient and family are instructed in its use, it does not require the assistance of a caregiver. For hospitalized patients, elimination of the need for a therapist could reduce health care costs. Long-term studies of the use of the Flutter seem justified to determine its effects on pulmonary function and outcome.

Adolescent↗
PubMed1994

Erosion of the wall of the frontal sinus caused by mucopyocele in cystic fibrosis.

Three patients with cystic fibrosis had complete erosion of one of the walls of a frontal sinus caused by a mucopyocele. Only fibrous tissue then separated the purulent contents of the sinus from the orbit or central nervous system. Initial surgery was unsuccessful, but two patients have remained free of symptoms after a second obliterating procedure. Sinus mucocele must be excluded by appropriate radiographic techniques when patients with cystic fibrosis have severe frontal headache and acute ophthalmologic symptoms.

Adult↗
PubMed1994

Maternal child-rearing behavior in three groups: cystic fibrosis, insulin-dependent diabetes mellitus, and healthy children.

Compared child-rearing behaviors among mothers of children (ages 4-14) with cystic fibrosis (CF) (N = 26), insulin-dependent diabetes mellitus (IDDM) (N = 26), and mothers of physically healthy children (N = 26), on six domains, including involvement, limit setting, responsiveness, reasoning and guidance, free expression, and intimacy using the Iowa Parent Behavior Inventory. Maternal Reports of their child-rearing behavior were comparable across the three groups with one exception: Mothers of children with chronic illnesses (CF and IDDM) were significantly less likely to set limits than mothers of healthy children. The present findings are consistent with those of other studies that have identified few differences in child-rearing practices between mothers of children with chronic illnesses and mothers of healthy children. Future research should identify situation-specific parenting tasks unique to childhood chronic illness.

Adolescent↗
PubMed1994

Spontaneous bacterial peritonitis in cystic fibrosis.

Bacterial peritonitis presents with classic symptoms of fever and abdominal pain. Some patients, however, are completely asymptomatic. Death in the short term is considerable, especially in patients with alcoholic cirrhosis. Cystic fibrosis patients occasionally develop biliary cirrhosis and may have secondary hypersplenism, varices, and ascites. These patients should be at risk for spontaneous bacterial peritonitis. Spontaneous bacterial peritonitis is described in two patients with longstanding hepatic cirrhosis secondary to cystic fibrosis. Both had required splenectomy for complications of portal hypertension. This is a previously unreported, but potentially fatal, complication of cystic fibrosis liver disease. Early diagnostic paracentesis is essential so that appropriate acute management, including antimicrobial treatment can be started. In the long term, these patients deserve immediate paracentesis for any evidence of recurrence. Whether the patient is treated with chronic (continuous) antimicrobial prophylaxis or only receives antimicrobial treatment during periods when bacteraemia is possible (for example, dental work, bronchoscopy), it would seem reasonable in patients with cystic fibrosis to use a wide spectrum antimicrobial agent with activity against Pseudomonas aeruginosa, other common Gram negative organisms, and Staphylococcus aureus.

Adolescent↗
PubMed1994

Restoration of exocrine pancreatic function following pancreas-liver-kidney transplantation in a cystic fibrosis patient.

Pancreatic transplantation for endocrine replacement is well-established for insulin-dependent diabetes mellitus. Exocrine pancreatic function after pancreas transplantation has been maintained after orthotopic cluster transplants for malignancy, and restoration of adequate exocrine function in a previously deficient patient has been reported in a patient with chronic pancreatitis who developed labile diabetes and steatorrhea after pancreatectomy. We performed a triple organ transplant (pancreas, liver and kidney) in a patient with exocrine pancreatic insufficiency and insulin-dependent diabetes related to cystic fibrosis (CF) after he developed hepatic and renal failure. Pancreatic exocrine secretions were drained enterically to the jejunum. At 24-month follow-up, malabsorption is absent. The 3-day stool fat, stool trypsin and chymotrypsin are normal. Serum carotene is within the normal range. Exocrine pancreatic insufficiency in CF patients can be corrected by pancreas transplantation. However, routine use in CF is precluded by the risks of surgery and immunosuppression. For diabetic patients with pancreatic exocrine insufficiency who require another organ transplant (e.g., lung, liver, or kidney), simultaneous pancreas transplantation with the exocrine secretions directed into the upper gastrointestinal tract should be considered.

Adult↗
PubMed1993

Multiplex PCR amplification from the CFTR gene using DNA prepared from buccal brushes/swabs.

Traditionally, DNA used for PCR-based diagnostic analysis has originated from white cells fractionated from whole blood. Although this method yields substantial quantities of DNA, there are some drawbacks to the procedure, including the inconvenience of drawing blood, risk of exposure to blood-borne pathogens, liquid sample handling, and the somewhat involved extraction procedure. Alternatively, DNA for genetic diagnosis has been derived from finger stick blood samples, hair roots, cheek scrapings, and urine samples. Oral saline rinses have also been used extensively as a means of collecting buccal epithelial cells as a DNA source. However, this method still requires liquid sample handling. Herein, we present our results involving the rapid extraction of DNA from buccal cells collected on cytology brushes and swabs for use in PCR reactions, specifically the multiplex amplification of 5 exons within the CFTR gene. The quality of DNA isolated from buccal cells, collected in this manner, has been sufficient to reproducibly support multiplex amplification. Cheek cell samples and the DNA prepared from them as described here are highly stable. The success rate of PCR amplification on DNA prepared from buccal cells is 99%. In a blind study comparing the analysis of 12 mutations responsible for cystic fibrosis in multiplex products amplified with DNA from both blood and buccal cell samples from 464 individuals, there was 100% correlation of results for blood and cheek cell DNA, validating the use of DNA extracted from cheek cells collected on cytology brushes for use in genetic testing.

Base Sequence↗
PubMed1992

Characterization of an intron 12 splice donor mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

Cystic fibrosis, the most common lethal genetic disease in the white population, is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Analysis of DNA from a pancreatic insufficient patient by chemical mismatch cleavage and subsequent DNA sequencing led to the identification of a potential splice mutation in the CFTR gene. A transition of the invariant guanosine to adenosine (1898 + 1G > A) was found at the splice donor site of intron 12. To determine the effect of this mutation on the patient's CFTR transcripts, RNA from the nasal epithelium was reverse transcribed and amplified by the polymerase chain reaction (RT-PCR). Direct sequencing of the PCR products revealed that the transcript from the chromosome with the 1898 + 1G > A mutation had skipped exon 12 entirely, resulting in a joining of exons 11 and 13. Deletion of exon 12 results in the removal of a highly conserved region which encodes the Walker B consensus sequence of the first nucleotide-binding fold of CFTR.

Adult↗
PubMed1992

Use of nonmedical treatment by cystic fibrosis patients.

To determine frequency, perceived effectiveness, and cost of religious, physical, and other nonmedical practices, we interviewed all (n = 402; 100% participation) of our cystic fibrosis patients/families [age, 0-45 (median, 18) years]. At least one type of nonmedical therapy was used by/on 264 (66%), two-thirds of which was religious. Most respondents perceived benefit (e.g., group prayer, 95%; religious articles, 81%; chiropractic, 69%). Only 17 (4.2%) invested over $200 lifetime (minimal compared with medical costs). These treatments, apparently used by most patients/families, rarely interfered with medical care. Physician openness and empathy toward patients' beliefs might enhance rapport and facilitate discussion of possible helpful or adverse effects of nonmedical treatment.

Adolescent↗
PubMed1992

The nasal response to exercise in patients with cystic fibrosis.

This study has evaluated the nasal response to exercise in patients with cystic fibrosis (CF), a genetic disease in which factors such as chronic lung disease and/or nasal polyposis might be anticipated to modify nasal function responses. Measurements of nasal resistance (NAR) by posterior rhinomanometry and specific airway resistance (sRAW) were made before and 1, 5, 10, and 30 min after a 4-min period of exhausting legwork exercise (50% predicted maximal) in 19 CF patients (aged 11-29 years) and 10 healthy subjects (aged 11-31 years). One minute after exercise, healthy subjects showed a 54 +/- 5% (mean +/- SEM; standard error of the mean) relative fall from baseline in NAR and CF patients showed a 31 +/- 8% relative fall from baseline (p < 0.05). There were no significant differences in the magnitude or pattern of recovery in NAR after exercise (1 to 30 min) between the groups, largely because of the variability in NAR responses in CF patients. Exercise did not result in significant changes in sRAW in either group. We also found that a history or presence of nasal polyposis does not significantly affect functional nasal responses to exercise. Our conclusion is that the CF genotype and its airway sequelae do not substantively affect the control of the nasal response to exercise.

Adolescent↗
PubMed1991

Longitudinal serum IgG response to Pseudomonas cepacia surface antigens in cystic fibrosis.

In cystic fibrosis (CF), serum antibody against surface antigens of Pseudomonas aeruginosa is detected only after colonization. Since pulmonary acquisition of P. cepacia usually follows colonization with P. aeruginosa and since P. aeruginosa-colonized patients with CF have demonstrable antibody against outer membrane proteins of P. cepacia, it appears that acquisition of the latter organism occurs in the presence of specific serum antibody. To test this hypothesis, serum obtained from six P. aeruginosa-colonized patients 4 and 2 years prior to and 3 months and 2 years after P. cepacia colonization were assayed for total and specific IgG to P. cepacia outer membrane components. Four patients demonstrated 6-fold or greater increases in specific IgG titers to whole outer membranes following colonization. By immunoblot, all patients had demonstrable serum IgG against the 27- and 36-kDa outer membrane proteins of P. cepacia 4 and 2 years prior to colonization. Immunoblots after P. cepacia acquisition demonstrated an intensification of the 28- and 36-kDa bands and the appearance of antibody to a very low molecular weight compound which was not hydrolyzed by proteinase K and was present in purified LPS. These observations suggest that low serum titers of antibody against two P. cepacia outer membrane proteins are present in patients with CF prior to P. cepacia colonization, and that these antibodies fail to protect for intrinsic or extrinsic reasons.

Adolescent↗
PubMed1991

Halothane inhibits two components of calcium current in clonal (GH3) pituitary cells.

The effect of halothane on isolated calcium (Ca2+) current of clonal (GH3) pituitary cells was investigated using standard whole-cell clamp techniques at room temperature. Halothane (0.1-5.0 mM) reversibly reduced both the low-threshold, transient [low-voltage-activated (LVA)] component and the high-threshold [high-voltage-activated (HVA)] component of Ca2+ current. Halothane had little effect on the voltage dependence of activation or inactivation of either component of Ca2+ current. Inhibition of the peak high-threshold Ca2+ current was half-maximal at about 0.8 mM halothane, with maximal inhibition (100%) occurring with 5 mM halothane. When measured at the end of a 190-msec command step, half-maximal reduction of high-threshold current occurred at less than 0.5 mM halothane. The low-threshold transient current was less sensitive to halothane, with half-maximal inhibition of peak transient current activated at -30 mV occurring at approximately 1.3 mM. The effect of halothane on the HVA current was apparently not mediated by changes in intracellular Ca2+ concentration. The ability of halothane to inhibit Ca2+ current was unaffected by either the inclusion of the rapid Ca2+ buffer 1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid (BAPTA) in the recording pipette or exposure of the cell to 10 mM caffeine. To assess the selectivity of the effect of halothane, the actions of halothane on two components of voltage-activated potassium (K+) current observed in the absence of extracellular Ca2+ and on voltage-dependent sodium (Na+) current were also examined. Halothane had no effect on the voltage-dependent, inactivating K+ current of GH3 cells at concentrations up to 1.2 mM. In contrast, the non-inactivating K+ current, though less sensitive to halothane than either Ca2+ current, was reduced by about 40% by 1.2 mM halothane at +20 mV. Peak Na+ current was also blocked by halothane, but 50% block required around 2.6 mM halothane with little effect at 1.6 mM. Reduction of Na+ current was associated with a substantial negative shift in the steady-state inactivation curve. Although the results indicate that a number of voltage-dependent ionic currents are sensitive to halothane, both components of Ca2+ current exhibit a greater sensitivity to halothane than any of three other voltage-dependent currents in GH3 cells. These results show that GH3 cell Ca2+ currents are selectively inhibited by clinically appropriate concentrations of halothane and that the reduction of Ca2+ current can account for the inhibition by halothane of TRH- or KCl-induced prolactin secretion in GH3 cells.

Calcium Channels↗
PubMed1991

The action of halothane on stimulus-secretion coupling in clonal (GH3) pituitary cells.

The effect of halothane on the physiological response to excitatory stimuli was assessed in clonal (GH3) pituitary cells. Halothane, at concentrations used to produce general anesthesia in animals (0.25-0.76 mM), inhibited thyrotropin-releasing hormone (TRH)-induced prolactin (PRL) secretion. The sustained (extracellular calcium-dependent) phase of PRL secretion was 70 +/- 7% inhibited by the highest concentration of halothane tested (0.76 mM); 50% inhibition was produced by approximately 0.4 mM halothane. The early (largely inositol trisphosphate-mediated) phase of secretion was less sensitive to halothane; 0.76 mM halothane produced 18 +/- 2% inhibition of the early phase of secretion. Consistent with these observations, halothane inhibited (IC50 approximately 0.45 mM) the sustained phase of the TRH-induced rise in intracellular calcium ([Ca2+]i) to a greater extent than the initial [Ca2+]i peak. The sustained phase of the [Ca2+]i elevation was inhibited by 75 +/- 7% at the highest concentration of halothane tested (0.76 mM), whereas the peak [Ca2+]i was only inhibited by 14 +/- 5%, consistent with the observation that halothane did not inhibit TRH-stimulated inositide hydrolysis in these cells. Halothane (0.5 mM) did not inhibit phorbol ester- or ionomycin-induced PRL secretion, indicating that halothane has inconsequential effects on the secretory apparatus. Halothane (0.5 mM) also inhibited KCl-induced PRL secretion by 50-80% and the corresponding KCl-induced rise in [Ca2+]i by 68 +/- 6%. These data indicate that halothane inhibits secretagogue-stimulated PRL secretion by reducing the elevation of [Ca2+]i produced by calcium (Ca2+) influx.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium↗
PubMed1991

Two frameshift mutations in the cystic fibrosis gene.

Cystic fibrosis (CF) is a recessive disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. We have identified in exon 7 two frameshift mutations, one caused by a two-nucleotide insertion and the other caused by a one-nucleotide deletion; these mutations--CF1154insTC and CF1213delT, respectively, are predicted to shift the reading frame of the protein and to introduce UAA(ochre) termination codons at residues 369 and 368.

Adolescent↗
PubMed1990

Person-to-person transmission of Pseudomonas cepacia between patients with cystic fibrosis.

Ribotyping, a method of strain identification based on analysis of bacterial genomic restriction fragment length polymorphisms, was used to investigate the acquisition of Pseudomonas cepacia by a patient with cystic fibrosis. Analysis of isolates recovered from the index patient and his contacts showed person-to-person transmission of this opportunist organism. This documentation of the transmission of P cepacia from one cystic fibrosis patient to another suggests that measures to limit the acquisition of the pathogen by patients with cystic fibrosis may be worth while.

Adult↗
PubMed1990

Monocytes in cystic fibrosis: responsiveness to microbial stimuli.

Peripheral blood monocytes were obtained from 19 patients with cystic fibrosis (CF) and age-matched paired normal individuals. The oxidative metabolic response of these cells was measured by superoxide anion production before and after stimulation with Salmonella typhimurium or Pseudomonas aeruginosa lipopolysaccharide (LPS). CF monocytes showed slightly greater spontaneous superoxide anion production (14.1 +/- 2.1 SEM nanomoles superoxide anion/10(6) monocytes/180 min; n = 12) than normal monocytes (9.5 +/- 1.4; n = 12), P = 0.009. No differences between CF and normals were found in LPS-stimulated superoxide anion production (CF = 33.5 +/- 4.6, n = 13; normal = 33.8 +/- 4.2, n = 13). Furthermore, CF monocytes responded to both P. aeruginosa and S. typhimurium LPS stimulation as well as to recombinant interferon-gamma. Superoxide anion production of CF monocytes was comparable in autologous serum and in normal serum, and responses of patients colonized with P. aeruginosa and P. cepacia did not differ. We conclude that CF monocytes have a slightly increased metabolic level and, despite chronic infection, are capable of a further response to exogenous microbial stimuli.

Adolescent↗