Fetal development in experimental uremia

Summary Uremic women on hemodialysis with metabolic bone disease (hyperparathyroidism, osteomalacia resulting from defective vitamin D metabolism) and anemia (erythropoietin deficiency) are known to give birth to infants without bone disease or anemia. Therefore, skeletal development (enchondral and desmal bone formation) and hepatic erythropoiesis were evaluated in fetuses of uremic rats. These fetuses failed to show defective mineralisation or evidence of bone disease. Bolus injection of high doses of exogenous PTH into the maternal or fetal organism did not affect fetal bone histology. In addition, no apparent defect of bone mineralisation or bone formation was found in fetuses of ricketic rats. Normal mineralisation in the offspring of uremic rats may be explained by fetal hyperphosphatemia and/or insensitivity of fetal (woven) bone mineralisation to vitamin D.Absence of fetal anemia (normal hematocrits, normal density of hematopoietic cells in the liver) in the presence of maternal anemia is presumably due to the insensitivity of fetal erythropoiesis to erythropoietin.With the support of Deutsche Forschungsgemeinschaft     

Multihormonal,amyloid-producing tumour of the islets of Langerhans in a twelve year old boy

Summary Clinical, pathological and biochemical data from a twelve year old boy with hypoglycaemic attacks and hyperinsulinism are presented. A pancreatic islet cell adenoma was diagnosed by ultrasonic scanning and enucleated from the head of the pancreas. Histological study revealed a mixed cellular population consisting of A₁- and B-cells. Large amounts of extravascular amyloid deposited were found between the cell strands. The tumour extract produced a prompt elevation of gastric acid secretion in the rat gastrin bio-assay. It is concluded that this islet cell tumour was a combined gastrinoma-insulinoma. The possible pathogenesis of this variety of the multiple endocrine adenoma syndrome is discussed. Monocellular-multihormonal islet cell tumours might arise from biochemically multipotent endocrine stem cells, whereas the multicellular-multihormonal type could either be a regulatory neoplasia or be derived from different neuroendocrine cells.

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Zusammenfassung Bei einem übergewichtigen 12jährigen Knaben mit Hypoglykämieanfällen und erhöhtem Blutinsulinspiegel konnte durch Ultraschall ein Tumor des Pankreaskopfes dargestellt werden. Das exstirpierte Gewebe erwies sich histologisch als ein aus A₁- und B-Zellen aufgebautes Inselzelladenom mit ausgedehnten extravasculären Amyloidablagerungen. Ein Extrakt aus dem Tumorgewebe bewirkte eine sofortige Zunahme der Magensäuresekretion am perfundierten Rattenmagen. Diagnose: Insulinom-Gastrinom. Monocellulärplurihormonelle Inselzelltumoren leiten sich möglicherweise von biochemisch pluripotenten Stammzellen der Langerhansschen Inseln her. Pluricellulär-plurihormonelle Adenome sind hingegen eher als Regulationsgeschwülste aufzufassen, könnten aber auch von verschiedenen neuroendokrinen Zellen abstammen.

     

Ectodermal dysplasia with acanthosis nigricans (Lelis syndrome)

A 31-year-old male patient with ectodermal dysplasia and acanthosis nigricans is described. Clinical findings included hypotrichosis, hypohidrosis, palmoplantar hyperkeratosis, nail dystrophy, early onset loss of permanent dentition, mental retardation, and acanthosis nigricans. The findings suggest the diagnosis of Lelis syndrome, as described on the basis of seven unrelated cases. A review concerning this condition is also presented.     

Karl Rokitansky: his Bohemian years and his relationship with Jan Evangelista Purkyne: on the occasion of bicentenary of birth

Karl Rokitansky was born on 19th February 1804 in the historic Czech town of Hradec Králové (K?niggr?tz). During 1821-1824 he studied for 3 years at the medical faculty of Prague University. In the archives of Charles University there is a record of Rokitansky's performance during these three years. At the university he met J. E. Purkyne who was teaching anatomy at that time. Relationship between the two world--renowned medical scientists of Czech origin is discussed.     

Ionic conductances of cultured principal cell epithelium of renal collecting duct

The ionic conductive properties were studied of epithelia of collecting duct principal cells which had been grown in primary tissue culture from renal cortex/capsule explants. When pretreated with aldosterone (10^–6 mol/l) and bathed on either surface with isotonic HCO ₃ ^– -free Ringer's solution, the transepithelial voltage,V _te, varied between –21 and –72 mV (apical surface negative) while the transepithelial resistance,R _te, ranged from 0.4 to 1.5 kcm². By 10:1 step-changes in Na⁺ concentration the apical cell membrane was shown to have a high conductivity for sodium, inhibitable by amiloride, 10^–6 mol/l. However, contrary to observations in natural collecting duct under control conditions, amiloride never reversed the polarity ofV _te even at 10^–4 mol/l. Both the apical and the basolateral cell membranes were conductive for potassium and both conductivities were inhibitable by Ba²⁺ (5 mmol/l). 10:1 reduction of apical Cl^– concentration strongly hyperpolarizedV _te with a monophasic time course suggesting the presence of a paracellular shunt conductance for Cl^–. In addition there may be a small Cl^– conductance present in the apical cell membrane since apical application of the chloride channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPAB) at 10^–7 mol/l produced a minute but significant hyperpolarization. On the other hand, 10:1 reduction of basolateral Cl^– concentration caused a biphasic change inV _te (initial depolarization, followed by repolarization) which indicates the presence of a large Cl^– conductance in the basolateral cell membrane. The latter was not inhibitable by 10^–7 mol/l NPPAB. Higher concentrations of this and of an other Cl^– channel blocker produced non-specific effects. In conclusion, our studies of a pure principal cell epithelium confirm findings described for the intact cortical collecting duct and add new information concerning chloride conductivity and related blocking agents.Dedicated to Prof. Dr. H. Sitte, Homburg, FRG, upon his 60th birthday.     

Fast network oscillations in the rat dentate gyrus in vitro

The dentate gyrus is a prominent source of gamma frequency activity in the hippocampal formation in vivo. Here we show that transient epochs of gamma frequency network activity (67 +/- 12 Hz) can be generated in the dentate gyrus of rat hippocampal slices, following brief pressure ejections of a high-molarity potassium solution onto the molecular layer. Oscillatory activity remains synchronized over distances >300 microm and is accompanied by a modest rise in [K(+)](o). Gamma frequency oscillations were abolished by a GABA(A) receptor antagonist demonstrating their dependence on rhythmic inhibition. However, in many cases, higher frequency oscillations (>80 Hz) remained in the absence of synaptic transmission, thus demonstrating that nonsynaptic factors may underlie fast oscillatory activity.     

Six new DPB1 alleles identified in a study of 1,302 unrelated bone marrow donor-recipient pairs

Six new DPB1 alleles were identified by PCR-SSOP methodologies in the course of a retrospective study of the role of HLA matching in the outcome of unrelated donor bone marrow transplantation. Sequencing confirmed that five of these alleles (DPB1*5901, *6801, *7101, *7201, and *7301) represent novel combinations of previously described sequence motifs in the variable regions of DPB1; the sixth (DPB1*7001) appears to result from a novel point mutation. These data support previous observations which suggest that multiple mechanisms, including segmental exchange and mutation, appear to be responsible for generating sequence diversity at the DPB1 locus. The extremely low discrepancy rate of 0.1% between the two laboratories which typed the samples, and the ability to predict the new sequences from probe hybridization patterns, indicate that SSOP is an accurate and efficient method for studying polymorphism at DPB1.     

Conservative treatment of cervical pregnancy by curettage and local prostaglandin injection

Recently, various conservative regimens for the treatment of cervical pregnancy have been introduced to preserve fertility in young women, with methotrexate being one of the most widely used drugs. The success of conservative treatment depends on early preoperative diagnosis. We report three cases of first trimester cervical pregnancy, successfully treated by curettage to evacuate the conceptus, followed by local prostaglandin instillation to prevent severe haemorrhage. In one patient, intra-amniotic instillation of hyperosmolar glucose was necessary to terminate fetal cardiac activity. beta-Human chorionic gonadotrophin returned to normal within 3 weeks in one patient and within 7 weeks in another, both of whom became pregnant again within 1 year, resulting in term deliveries. The third patient was lost to follow-up after 1 week. The advantage of prostaglandin and curettage is the absence of major side-effects to the mother or the fetus of a subsequent pregnancy. The management strategies used in the treatment of cervical pregnancies and the results obtained since the introduction of methotrexate in 1989 are discussed in the context of previously published literature. The incidence of subsequent pregnancies among women treated medically versus women treated surgically is reported.