Inheritance of male hybrid sterility in the house musk shrew (Suncus murinus, Insectivora, Soricidae)

Two geographic races of the house musk shrew (Suncus murinus) were crossed and intercrossed in the laboratory. Many cases of male sterility were detected among the hybrids. Segregation analysis of the pedigree data showed that the inheritance of male sterility in interracial hybrids of S. murinus can be described within the framework of monogene polyallele model with sterility of a single allele combination. This model is similar if not identical to that proposed by Dobzhansky and Muller.     

Expression of type 2 11beta-hydroxysteroid dehydrogenase and corticosteroid hormone receptors in early human fetal life

In adult life, the type 2 isozyme of 11beta-hydroxysteroid dehydrogenase (11betaHSD2) protects the mineralocorticoid receptor (MR) from glucocorticoid by inactivating cortisol to cortisone. 11betaHSD2 activity has been reported in human fetal tissues, where glucocorticoids may impair fetal growth yet are also required for normal fetal development. Using digoxigenin-labeled complementary ribonucleic acid (RNA) probes and an in-house 11betaHSD2 antiserum, we have analyzed the expression of 11betaHSD2, MR, and glucocorticoid receptor (GR) in human fetal tissues of gestational age 6-17 weeks (n=15). 11BetaHSD2 expression was absent at gestational age 6+ weeks, but was expressed in abundance in many fetal tissues between 8-12 weeks. At this time, 11betaHSD2 colocalized with GR messenger RNA (mRNA) expression in metanephros, gut, muscle, spinal cord and dorsal root ganglia, periderm, sex chords of testis, and adrenal. In particular within fetal kidney, intense expression of 11betaHSD2 and GR mRNA was observed over Bowman's capsule and the vascular tufts of developing glomeruli as they migrated from the surface of the kidney to the inner cortex. Only lung and adrenal medullary rests demonstrated high levels of GR mRNA but low levels of 11betaHSD2. 11BetaHSD2 mRNA and immunoreactivity staining patterns were similar, with the exception of the fetal adrenal, where mRNA was localized to the outer definitive zone but immunoreactivity was localized to the inner fetal zone. Colocalization of 11betaHSD2 (and GR mRNA) with MR mRNA was observed principally within epithelial cells of collecting ducts, particularly after 16 weeks gestation when the pattern of distribution of 11betaHSD2 became more adult in nature. High levels of MR mRNA were observed within developing bone. The data indicate that 11betaHSD2 in fetal life principally modulates ligand access to the GR in most fetal tissues, notably glomeruli and tubules in the developing kidney, testis, and periderm, and this may be have ramifications for fetal sodium homeostasis and differentiation. The development of tissues previously shown to have a critical requirement for glucocorticoids, such as lung and adrenal medulla, is facilitated by the expression of GR mRNA, but not 11betaHSD2. The expression of MR mRNA in high abundance in bone suggests a role for corticosteroids in human bone development, and the low/absent expression of 11betaHSD2 at this site suggests that it is functionally acting as a GR.     

Phylogeny of the Drosophila saltans species group based on combined analysis of nuclear and mitochondrial DNA sequences

Nucleotide sequences from two nuclear loci, alcohol dehydrogenase and internal transcribed spacer-1 of the nuclear ribosomal DNA repeats, and two mitochondrial genes, cytochrome oxidase I and cytochrome oxidase II, were determined from nine species in the Drosophila saltans species group. The partition homogeneity test and partitioned Bremer support were used to measure incongruence between phylogenetic hypotheses generated from individual partitions. Individual loci were generally congruent with each other and consistent with the previously proposed morphological hypothesis, although they differed in level of resolution. Since extreme conflict between partitions did not exist, the data were combined and analyzed simultaneously. The total evidence method gave a more resolved and highly supported phylogeny, as indicated by bootstrap proportions and decay indices, than did any of the individual analyses. The cordata and elliptica subgroups, considered to have diverged early in the history of the D. saltans group, were sister taxa to the remainder of the saltans group. The sturtevanti subgroup, represented by D. milleri and D. sturtevanti, occupies an intermediate position in this phylogeny. The saltans and parasaltans subgroups are sister clades and occupy the most recently derived portion of the phylogeny. As with previous morphological studies, phylogenetic relationships within the saltans subgroup were not satisfactorily resolved by the molecular data.     

Thyroid function in lead smelter workers: absence of subacute or cumulative effects with moderate lead burdens

The electroencephalographic abnormalities seen in Landau-Kleffner syndrome (LKS) (language deterioration) are non-specific, and consist of a variety of epileptiform discharge patterns including continuous slow spike-wave discharges during sleep, focal sharp waves with spikes, and centrotemporal (rolandic) spikes. Similarly, the EEG abnormalities seen in autistic epileptiform regression (language and social/behavioral deterioration) are non-specific and overlap with those seen in LKS. By contrast, distinct epilepsy syndromes in otherwise normal children occur in the EEG-defined benign focal epilepsies of childhood. Occipital spikes or spike-wave present either in the older child with visual symptoms and headache or in the younger child with autonomic symptoms followed by brief or prolonged partial motor seizures. Seven young children (five from a consecutive series of 42) presenting clinically with autism or autistic regression and possible or definite seizures, whose EEGs revealed occipital spikes or spike-wave characteristic of the benign epilepsies, are reported. Although occipital spikes are commonly seen in young children as an age-dependent EEG-defined benign focal epilepsy, their high frequency in this population with cognitive difficulties suggests a possible causal relation. The effects of the epileptiform discharge on cognitive functioning presumably reflect extension into temporal and parietal lobes, rather than occipital disturbances per se.     

A primary care nurse clinic

A nurse-driven clinic that uses a client-centered approach evolved from an independent ambulatory care program. The clinic operates 4 to 5 hours per day and provides patient counseling, health care maintenance, primary care, patient education, and therapeutic care.     

Congenital bilateral perisylvian syndrome

The congenital bilateral perisylvian syndrome is characterized by pseudobulbar palsy, moderate delay in mental and motor development and epilepsy. Three characteristic case stories are presented. Epileptic seizures are most frequently generalized: tonic, astatic, atypical absences and tonic-clonic seizures. Partial seizures are less frequent. Seizure control is often unsatisfactory. Neuroimaging demonstrates thickening of the cerebral cortex in the perisylvian area bilaterally; these changes together with the clinical picture establish the diagnosis. The etiology is unknown.     

Laparoscopic adrenalectomy. An alternative to open surgery of minor adrenal tumors

In the period February 1994 to November 1995 11 laparoscopic adrenalectomies were performed at our institution (seven women, four men). A transperitoneal approach was used in both right- and left-sided operations. Results were collected retrospectively. Indications for surgery were: Conn's syndrome (four), Cushing's syndrome (two), phaecromocytoma (four), and incidentaloma (one). The operations took median 170 minutes (range 105-250 minutes). Median size of the tumour was 4 cm range 1(1/2)-5 cm). No significant peri- or postoperative complications were recorded. The patients were discharged from the surgical unit median two days after surgery. Laparoscopic operation emerges as an alternative to open operation when dealing with smaller adrenal tumours. Because of the small number of patients, these operations have to be restricted to a few centres where both internists, anaesthesiologists and surgeons with expertise in this field are found.     

Mechanisms of expression of pyruvate dehydrogenase deficiency caused by an E1alpha subunit mutation

OBJECTIVE: To characterize the biochemical mechanisms of expression of the pyruvate dehydrogenase (PDH) E1alpha subunit exon 10 R302C missense mutation. BACKGROUND: Mutations in the X-linked E1alpha subunit gene are responsible for most cases of PDH deficiency, an important cause of neurodevelopmental defects and neurodegeneration with primary lactic acidemia. Although the disease shows extreme allelic heterogeneity, the R302C mutation has been defined in several unrelated cases. METHODS: Cell lines expressing selectively either the mutant or wild-type E1alpha alleles against identical genetic backgrounds were generated from the fibroblasts of a female heterozygous for the R302C mutation. Enzyme activity, mRNA, polypeptide expression, and turnover were studied in each. RESULTS: The residual PDH activity was below measurable levels in the cell line (B5) expressing only the mutant allele and normal in the wild-type polypeptide expressing (A10) cell line, confirming that the R302C mutation alone is sufficient to cause a severe PDH deficiency. The mutant polypeptide was less stable than the wild-type polypeptide, but the steady-state level of the mutant E1alpha protein was reduced only two- to threefold. CONCLUSIONS: The primary mechanism of expression of the R302C mutation must be limitation of catalytic efficiency. We speculate that catalysis may be inhibited in the mutant polypeptide because conformational changes are induced near serine 300, a residue that is particularly important as a regulatory phosphorylation site in the wild-type polypeptide.     

Surgical treatment of cyclosporine A- and nifedipine-induced gingival enlargement: gingivectomy versus periodontal flap

The purpose of this study was to compare probing depth resolution achieved by gingivectomy and periodontal flap techniques in the treatment of cyclosporine A- and nifedipine-induced gingival enlargement. Ten kidney transplant patients who were receiving cyclosporine A and nifedipine for at least 6 months participated in the study. Five patients were randomly assigned to the gingivectomy group and 5 patients to the periodontal flap group. Only anterior segments of the oral cavity (canine to canine) were surgically treated. Clinical measurements, including probing depths, plaque index, and gingival sulcus index, were taken at baseline, 6 weeks, 6 months, and 1 year. Results showed that probing depths, while similar for both groups in the first 6 weeks of the study, were significantly shallower for the periodontal flap group when compared to the gingivectomy group at 6 months (2.48 +/- 0.34 mm versus 4.87 +/- 0.79 mm, respectively) and 1 year (322 +/- 0.65 mm versus 6.40 +/- 1.02 mm, respectively). Within its limitations, this study suggests that the pocket reduction achieved by the periodontal flap may be sustained for longer periods of time than by the gingivectomy technique in the treatment of cyclosporine A- and nifedipine-induced gingival enlargement.