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Biomedical subjects

B Buehler

Publications and source records attributed to B Buehler.

12 recordsLinked to original sources

Elemental composition of liver and kidney tissues of rough-toothed dolphins (Steno bredanensis).

On December 14, 1997, 62 rough-toothed dolphins (Steno bredanensis) stranded on Cape San Blas, on the Florida coast of the Gulf of Mexico. Approximately 30 animals died either on the beach or in rehabilitation facilities. Two were successfully rehabilitated and released. Liver, kidney, blubber, and muscle tissues were collected from 15 animals that died on the beach. Portions of the liver and kidney from each dolphin were analyzed using instrumental neutron activation analysis and inductively coupled plasma mass spectrometry to determine mass fractions of 37 elements. Levels of several electrolytes (Na, Cl, K, Br, Rb, I, Cs) and of the essential trace elements Fe, Cu, and Zn in both tissues were similar to those found in other Odontoceti. Mass fractions of Ca ranged from 60 mg/kg to 1,200 mg/kg (wet mass basis), indicating significant inhomogeneity in the kidney tissues of several animals. Necropsy reports noted that the kidneys of many of these animals contained fibrous nodules. The measured Ca inhomogeneity may be due to mineralization of the fibrous kidney tissue. Hepatic levels of Hg and Se were at the high end of the ranges generally found in livers of other Odontoceti and were slightly higher in animals with fibrous kidneys than in the others. Mass fractions of Se, Ag, and Hg in liver tissues increased with the size and age of the animals indicating accumulation of these elements in the liver with age. Results also indicate that Se and Hg accumulate in rough-toothed dolphin kidney. Accumulation of these elements with age has been reported commonly for marine mammals and other species.

Adipose Tissue↗

The spectrum of pathogenic mutations in SPINK5 in 19 families with Netherton syndrome: implications for mutation detection and first case of prenatal diagnosis.

The Comèl-Netherton syndrome is an autosomal recessive multisystemic disorder characterized by localized or generalized congenital ichthyosis, hair shaft abnormalities, immune deficiency, and markedly elevated IgE levels. Life-threatening complications during infancy include temperature and electrolyte imbalance, recurrent infections, and failure to thrive. To study the clinical presentations of the Comèl-Netherton syndrome and its molecular cause, we ascertained 19 unrelated families of various ethnic backgrounds. Results of initial linkage studies mapped the Comèl-Netherton syndrome in 12 multiplex families to a 12 cM interval on 5q32, thus confirming genetic homogeneity of Comèl-Netherton syndrome across families of different origins. The Comèl-Netherton syndrome region harbors the SPINK5 gene, which encodes a multidomain serine protease inhibitor (LEKTI) predominantly expressed in epithelial and lymphoid tissues. Recently, recessive mutations in SPINK5 were identified in several Comèl-Netherton syndrome patients from consanguineous families. We used heteroduplex analysis followed by direct DNA sequencing to screen all 33 exons and flanking intronic sequences of SPINK5 in the affected individuals of our cohort. Mutation analysis revealed 17 distinct mutations, 15 of which were novel, segregating in 14 Comèl-Netherton syndrome families. The nucleotide changes included four non-sense mutations, eight small deletions or insertions leading to frameshift, and five splice site defects, all of which are expected to result in premature terminated or altered translation of SPINK5. Almost half of the mutations clustered between exons 2 and 8, including two recurrent mutations. Genotype-phenotype correlations suggested that homozygous nucleotide changes resulting in early truncation of LEKT1 are associated with a severe phenotype. For the first time, we used molecular data to perform prenatal testing, thus demonstrating the feasibility of molecular diagnosis in the Comèl-Netherton syndrome.

Adolescent↗

Familial inverted duplication 7p.

A 10-month-old female with developmental delay and failure to thrive was referred for genetic evaluation as part of an adoption assessment. Physical exam showed a mildly beaked nose and clinodactyly, but otherwise nothing remarkable. Chromosome analysis showed an inverted duplication of the p12.2-->p13 portion of chromosome 7[(46,XX, dup(7)(p13p12.2)]. The proposita's older brother, mother, and grandmother were cognitively delayed and had the same chromosome 7 duplication. A review of the literature showed no other cases involving this exact duplication.

Chromosome Inversion↗

Partial deletion of distal 17q.

A newborn female was found to have a deletion of the terminal portion of 17q. Prominent manifestations included microcephaly, apparent hypertelorism, epicanthic folds, a broad nasal bridge with anteverted nostrils, posteriorly angulated ears, micrognathia, widely spaced nipples, arachnodactyly with proximal thumbs, and a coxa vara deformity. The unbalanced translocation was inherited from the mother, who had a reciprocal translocation involving the terminal portions of 2p and 17q. To the best of our knowledge, this is the first report of a liveborn infant with deletion of the distal portion of 17q with the exception of reports of patients with ring chromosome 17.

Abnormalities, Multiple↗

Partial duplication of distal 17q.

A male propositus and an older sister had a similar pattern of congenital anomalies, including facial asymmetry with hypertelorism, frontal bossing and temporal narrowness, a broad nasal bridge, epicanthal folds, a wide mouth with a thin upper lip, micrognathia, webbed neck, low-set posteriorly angulated ears, and an abnormal hairline. There was also postaxial polydactyly, flexion contractures of the digits, hypotonia, and a congenital heart anomaly. The propositus also had renal anomalies whereas the sister did not, and the sister had a cleft lip and palate not present in her brother. The propositus and a subsequent fetus identified through genetic amniocentesis were determined to have a 46, XY, -18, +der(18),t(17;18)(q25.1;q23)mat chromosome constitution. Clinical findings are compared to those of other reported cases of dup(17q).

Abnormalities, Multiple↗

Ornithine decarboxylase and S-adenosyl methionine decarboxylase in skin fibroblasts of normal and cystic fibrosis patients.

The key enzymes in the synthesis of the naturally occurring polyamines, ornithine decarboxylase (ODC) and S-adenosyl methionine (SAM) decarboxylase, were investigated during cell growth and aging in fibroblast cultures from normal patients and patients with cystic fibrosis. A linear correlation between increased S-adenosyl methionine activity and putrescine concentration was apparent in all cell lines. A putrescine concentration of 0.8 mM was optimal for enhancement of SAM decarboxylase activity. The passage number of the cell line correlated inversely with maximal putrescine-stimulated SAM decarboxylase activity, earlier passage numbers having the highest specific activity (Fig. 1). No significant differences in basal or putrescine-stimulated SAM decarboxylase activity were noted between normal fibroblast cultures and cells from patients with cystic fibrosis (Fig. 2). SAM decarboxylase activity increased as the cell lines approached confluence. Activity was lowest during exponential growth (Fig. 3). ODC activity was increased during early exponential growth and fell as cells reached confluence (Fig. 4). No differences in ODC activity and putrescine inhibition between the normal and cystic fibrosis cell cultures at equivalent points of exponential growth were noted.

Adenosylmethionine Decarboxylase↗