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Biomedical subjects

R E Pyeritz

Publications and source records attributed to R E Pyeritz.

At least 127 records · Page 7Linked to original sources
PubMed1987

The economics of clinical genetics services. I. Preview.

To an ever increasing extent, a variety of economic factors are affecting the delivery of clinical genetics services. These economic factors, which we enumerate with an historical perspective, influence how genetics professionals, patients, and third-party payers relate to genetics services. From the perspectives of each of these interested parties, the deficiency of objective information about the current economic situation is striking. The recent history of charges and reimbursement for our genetics clinic illustrates both one kind of data that is readily available and how modification of administrative procedures can improve the economic balance sheet. However, several characteristics of clinical genetics limit the possibility of economic self-sufficiency.

Cost-Benefit Analysis↗
PubMed1987

The economics of clinical genetics services. II. A time analysis of a medical genetics clinic.

In a time-and-reimbursement analysis of our clinical genetics service, we documented (1) the time spent by professionals and staff in serving families before, during, and after the clinic visit; (2) the charges and reimbursement for the services provided; and (3) the relationship between income from clinical practice and the personnel costs of the clinic. We found that newly referred and returning families required 7.1 and 4.0 h, respectively. Average collections for professional services were +135 (+19/h) for new families and +49 (+12/h) for returning families. Income from clinical practice covered 37% of the clinical portion of personnel costs. These results indicate that cognitive clinical genetics services are labor intensive, yield low payments per service hour, and are not financially self-supporting. To improve the economic status of genetics clinics, administrators might consider rendering services more efficiently; increasing charges for services; billing for all services provided to all family members; billing for all genetics professionals, including counselors and social workers; and requesting payment at the time of service.

Cost-Benefit Analysis↗
PubMed1986

Surgical treatment of aneurysms of the ascending aorta in the Marfan syndrome. Results of composite-graft repair in 50 patients.

The life expectancy of patients with the Marfan syndrome is reduced by complications caused by dilatation of the ascending aorta. Because surgical therapy with a composite graft may alter this natural history, we analyzed the preoperative and long-term postoperative status of 50 consecutive patients who received such a graft. At surgery, the patients had a mean age of 32.2 years and a mean aortic diameter of 7.1 cm (range, 5.3 to 10). Dissection of the ascending aorta was present in 14 patients and was acute in 5. None of the 44 patients who underwent elective repair, and only one of the six patients who had emergency surgery, died in the hospital; thus, the overall hospital mortality was 2 percent. Five of the 49 survivors died during a follow-up period of up to eight years (10.2 percent late mortality). During the most recent four years of evaluation of this series (38 patients), no postoperative deaths due to intrathoracic problems occurred. Actuarial survival was 87 percent at both two and five years. Composite-graft repair of the ascending aorta in patients with the Marfan syndrome can be performed with low operative and long-term mortality. Because of the unfavorable natural history of the Marfan syndrome and the potential for dissection in moderately dilated aortic roots, we recommend prophylactic repair when the aneurysm reaches a diameter of 6 cm.

Adolescent↗
PubMed1986

Homeostasis. VII. A conspectus.

The characteristics and properties of physiological homeostasis are broadly reviewed in terms that should pave the way for definitive genetic analysis. The ideas are illustrated by common physiological and pathophysiological examples with special reference to type II diabetes mellitus.

Adaptation, Physiological↗
PubMed1986

Pulmonary hypertension and interstitial fibrosis in von Recklinghausen neurofibromatosis.

Neurofibromatosis von Recklinghausen (NFvR) has been reported to be associated with diffuse interstitial pulmonary fibrosis. We describe a patient with NFvR presenting in middle age with dyspnea and cyanosis. Chest radiographs showed right ventricular enlargement, dilated proximal pulmonary arteries, and bilaterally increased interstitial markings. Cardiac catheterization showed moderately severe pulmonary hypertension and no evidence of congenital heart defect. The interstitial fibrosis associated with NFvR can result in symptomatic pulmonary hypertension.

Electrocardiography↗
PubMed1986

The Marfan syndrome.

Although the prognosis for a person with the Marfan syndrome is much more favorable than it was a decade ago, this remains a serious and burdensome condition. Early diagnosis is essential and is based on characteristic abnormalities of the musculoskeletal, ocular and cardiovascular systems and a positive family history for the syndrome. Management focuses on recognizing abnormalities and altering the natural history of each clinical manifestation at as young an age as possible. The family physician must be current with therapy and counseling.

Adolescent↗
PubMed1985

Relation of mitral valve prolapse to left ventricular size in Marfan's syndrome.

Sporadic recent reports suggest that mitral valve prolapse (MVP) disappears with progressive left ventricular (LV) dilatation. To test this hypothesis, we sought to determine if an inverse relation exists between MVP and LV cavity size on M-mode echocardiograms in 83 patients with Marfan's syndrome. LV end-diastolic dimensions and presence or absence of MVP were determined. Forty-six patients had MVP. Of patients with an LV end-diastolic dimension less than or equal to 5 cm, 90% had MVP; only 19% of the 32 patients with abnormally large (greater than 5.8 cm) end-diastolic dimension had MVP. The prevalence of MVP in patients with an LV end-diastolic dimension of 5.1 to 5.8 cm was 69%. Thus, the prevalence of MVP was inversely related to LV cavity size. To determine whether appearance or disappearance of MVP was associated with decrease or increase in LV cavity size, serial echocardiograms from 67 patients (mean follow-up 42 months, range 3 to 99) were examined. These patients were separated into 3 groups based on changes in the LV end-diastolic dimension of greater than 1 cm over time. Group 1 consisted of 9 patients, all of whom had MVP and normal LV cavity size on their initial study. With subsequent increase in LV end-diastolic dimension (mean 1.42 +/- 0.3), MVP disappeared in 6 of the 9. Conversely, group 2 consisted of 4 patients, all of whom had dilated left ventricles on their initial echocardiogram and no evidence of MVP. After aortic valve replacement, the LV cavity size decreased (mean 2.3 +/- 0.7) and MVP appeared on follow-up studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Synthesis of an altered type III procollagen in a patient with type IV Ehlers-Danlos syndrome. A structural change in the alpha 1(III) chain which makes the protein more susceptible to proteinases.

The synthesis of type III procollagen was examined in cultured fibroblasts from ten patients with type IV Ehlers-Danlos syndrome, a heritable disorder of connective tissue. With fibroblasts from nine patients, a decreased amount of labeled type III procollagen was recovered in the medium after the cells were incubated with radioactive amino acids for 24 h. The results were compatible with undefined defects in type III procollagen. The culture medium from one patient contained apparently normal amounts of type III procollagen after a 24-h labeling. However, the pro-alpha 1(III) chains from the medium of the patient's fibroblasts appeared as an abnormally broad band when examined by gel electrophoresis in sodium dodecyl sulfate. Analysis of fragments generated by vertebrate collagenase and cyanogen bromide located a structural defect between amino acid residues 555 and 775 in half of the alpha 1(III) chains. Most of the patient's type III procollagen was susceptible to digestion by pepsin or a mixture of chymotrypsin and trypsin at temperatures at which normal type III procollagen resisted digestion. Cyanogen bromide digestion of samples of the patient's skin revealed that the amount of type III was reduced more than 4-fold. The results support the hypothesis that both normal and structurally altered pro-alpha 1(III) chains are being incorporated into type III procollagen synthesized by the patient's fibroblasts and that type III procollagen molecules containing one, two, or three structurally altered pro-alpha 1(III) chains are rapidly degraded by proteinases in the tissues.

Cell Line↗
PubMed1985

Osteogenesis imperfecta with unusual skeletal lesions: report of three families.

Thirteen individuals with osteogenesis imperfecta (OI) from three families were evaluated. All examined persons with OI had multilocular radiolucent, radiopaque, or radiolucent-radiopaque lesions of the maxilla and mandible. In most patients, the lesions involved the tooth bearing areas, but in two, the rami also were involved. Teeth were normal. Radiologic findings in the extragnathic skeleton included marked coarseness of trabeculae and diffuse osteopenia. It is proposed that these patients represent yet another dominantly inherited OI syndrome.

Adolescent↗
PubMed1985

The natural history of homocystinuria due to cystathionine beta-synthase deficiency.

An international questionnaire survey has been conducted to define better the natural history of homocystinuria due to cystathionine beta-synthase deficiency and permit evaluation of treatment. Data were compiled for 629 patients. Among patients not discovered by newborn screening, B6-responsive individuals on the average have significantly better mental capabilities (mean IQ, 79) than do B6-nonresponsive individuals (mean IQ, 57). Time-to-event curves are presented for the other major clinical abnormalities produced by this disease. Each occurred at significantly lower rates in untreated B6-responsive than in untreated B6-nonresponsive patients, as shown by the following examples: (1) dislocation of optic lenses (at age 10, chances of dislocation: 55% and 82%, respectively); (2) initial clinically detected thromboembolic events (at age 15, chances of having had such an event: 12% and 27%, respectively); (3) radiologic detection of spinal osteoporosis (at age 15, chances of such osteoporosis having been detected: 36% and 64%, respectively); and (4) mortality (at age 30, chances of not surviving: 4% and 23%, respectively). Methionine restriction initiated neonatally prevented mental retardation, retarded the rate of lens dislocation, and may have reduced the incidence of seizures. Pyridoxine treatment of late-detected B6-responsive patients retarded the rate of occurrence of initial thromboembolic events. Following 586 surgical procedures, 25 postoperative thromboembolic complications occurred, six of which were fatal. Reproductive histories were reported predominantly for B6-responsive patients. Living offspring of either men or women patients had few abnormalities. The evidence is inconclusive whether untreated maternal cystathionine beta-synthase deficiency leads to excessive fetal loss. Only 13% of patients detected in screening programs of newborns and classified as to B6-responsiveness were B6-responsive, compared to 47% among late-detected patients. Current screening programs that identify neonatal hypermethioninemia may be preferentially failing to detect B6-responsive patients.

Adolescent↗
PubMed1984

Pseudoxanthoma elasticum: high calcium intake in early life correlates with severity.

The characteristic histopathologic lesion of pseudoxanthoma elasticum (PXE) is calcification of the central core of elastic fibers in affected organs; it is correlated with clinical severity. One hypothesis holds that lowering dietary calcium might reduce or prevent tissue injury and minimize clinical effects. This hypothesis would be supported by demonstrating that clinical expression is positively associated with previous calcium intake. We studied 32 unrelated PXE patients (20 men and 12 women, mean age 43 years, SE = 14.2, range = 13-71) by grading their clinical severity and their presumed calcium intake during childhood, adolescence, and adulthood. Overall severity in the study group varied greatly and correlated positively with age (P less than 0.001). Overall severity correlated positively with calcium ingestion as an adolescent (P less than 0.001, with the other predictor variables held constant). Overall cardiovascular and eye severity were a function of age (P less than 0.000001 for both), whereas skin severity was not. These results confirm that PXE is a highly variable condition that generally worsens with age and support the rationale for a clinical trial to determine the effects of different levels of dietary calcium ingestion in young PXE patients on their subsequent clinical course.

Adolescent↗
PubMed1984

Ehlers-Danlos syndrome IV due to a novel defect in type III procollagen.

Ehlers-Danlos syndrome type IV (EDS IV) is characterized by variable changes in the skin, arterial fragility, bowel perforation, minimal joint involvement, and either autosomal recessive or autosomal dominant inheritance. The unifying biochemical abnormality is a deficiency of type III collagen; all patients studied thus far have shown a defect in either synthesis or in secretion of type III procollagen. We report on an adolescent boy who inherited EDS IV from his father and who developed a spontaneous subclavian artery aneurysm. In vitro studies of collagen production in dermal fibroblasts showed normal amounts of pro alpha 1 (III) messenger RNA and synthesis and secretion of nearly equal amounts of normal and of structurally abnormal pro alpha 1 (III) monomers. This patient is biochemically distinct from previous cases of EDS IV and is likely heterozygous for a mutation that results in an aberrant type III procollagen that is particularly susceptible to protease degradation.

Adolescent↗
PubMed1984

Pneumothorax in the Marfan syndrome: prevalence and therapy.

At least twenty-four reports of pneumothorax associated with the Marfan syndrome have appeared in the medical literature, but the frequency and optimal method of treatment remain unclear. We conducted a retrospective review of medical records from one genetics clinic and found that the frequency of spontaneous pneumothorax in patients older than 12 years with Marfan's syndrome was 4.4% (11 out of 249). Men were more commonly, but no more severely, affected than women. Seven patients had recurrent or bilateral pneumothorax. In 9 of the 11 patients, apical bullae were present and detectable on chest radiograph. Pneumothorax frequently recurred if not treated by resection of the offending bullae. We recommend that all adolescent and adult patients with the Marfan syndrome undergo chest radiography for ascertainment of the gross pathological condition of the lung. Definitive surgical treatment should be performed at the first occurrence of pneumothorax because of the high rate of recurrence after treatment with a chest tube, with or without pleurodesis.

Adolescent↗
PubMed1984

Immunohistochemical localization of glycosphingolipid in urinary renal tubular cells in Fabry's disease.

Although the accumulation of neutral glycosphingolipid (GSL), principally globotriaosylceramide ( GbOse3Cer ), in the kidney of patients with Fabry's disease is well documented, little is known about the type and quantity of lipid present in the renal tubular cells shed in the urine. Using a variety of cytologic technics, the authors examined exfoliated cells found in the urine specimens of patients hemizygous and heterozygous for alpha-galactosidase A deficiency. Renal tubular cells contained periodic acid- Shiff positive material that could be identified easily by Papanicolaou stain. A fluorescein-labeled antibody specific for GbOse3Cer localized this lipid to the cytoplasm. Electron microscopy showed numerous electron-dense multilamellar membranous inclusions within phagolysosomes and electronlucent material within lysosomes of tubular cells. Based on immunofluorescence, heterozygote individuals had similar distribution but less quantity of cytoplasmic GSL. The authors conclude that in Fabry's disease GSL accumulates probably in lysosomes of renal tubular cells. These cells are exfoliated and can be identified specifically in voided urine specimens. Examination of renal tubular cells in urine using the fluorescein antibody technic described here affords a noninvasive means of diagnosing and following the effect of therapy in patients with Fabry's disease.

Adolescent↗
PubMed1983

The Marfan syndrome in early childhood: analysis of 15 patients diagnosed at less than 4 years of age.

The clinical, cardiac and echocardiographic features were reviewed of 15 consecutive infants and children with the Marfan syndrome who presented at less than 4 years of age. The 10 females and 5 males were diagnosed at a mean age of 18 months (range 2 days to 3.5 years); 13 were followed up for a mean of 45 months (range 8 to 109 months) and 2 were lost to follow-up. On first evaluation, 5 patients had mitral regurgitation (MR) and none had aortic regurgitation (AR). Echocardiography showed aortic root dilatation in 9 and mitral valve prolapse (MVP) in 9; only 2 patients had a normal echocardiogram. At follow-up examination, all patients had aortic root dilatation; the rate of increase in aortic root diameter was generally greater than predicted on the basis of body surface area. One patient had AR at age 10 years. All 13 patients had MVP; 9 had progressive mitral valve dysfunction and 4 had mitral valve replacement. One patient died immediately postoperatively. Thus, aortic root dilatation is usually present in early childhood and serves as an objective indicator of the Marfan syndrome. MVP is common and MR, which may require valve replacement, is the leading cause of cardiovascular morbidity in childhood. Echocardiography is useful in the diagnosis and routine management of infants and children in whom the Marfan syndrome is suspected.

Aortic Valve Insufficiency↗