Facts and challenges in respiratory neurobiology.

Respiratory neurobiology has been a lead discipline in the field of neuroscience for almost a century. Despite this, research studies on the fundamental synaptic and cellular processes underlying the generation and modulation of breathing movements suffered a significant decline during the last decade. We still believe that respiratory neurobiology is one of the most exciting and imperative fields of neuroscience. With the first white paper concerned with the central control of breathing, we want to celebrate the global importance of breathing research.

Reduction of craniofacial and palatal narrowing in very low birthweight infants.

Many infants born preterm have positional moulding of the head and palate. This study investigates whether specially designed, foam pressure dispersing pads (PDP) worn throughout the neonatal hospital course, were not only effective in reducing craniofacial flattening, but also in lessening palatal narrowing in very low birthweight (VLBW) infants. The study was conducted in two phases. Twenty-three consecutively born VLBW infants were randomly selected to act as a comparative group. The next 31 VLBW infants born comprised the intervention group, and wore PDP during hospitalization. The two groups were similar in birthweight and gestational age. The groups were compared for changes in craniofacial and palatal parameters at three time intervals during hospitalization. Results indicated a significant increase in growth of craniofacial width, palatal width and palatal area of infants wearing PDP compared to those infants not wearing them. These findings suggest that craniofacial and palatal narrowing observed in VLBW infants may be reduced by the wearing of PDP during hospitalization.

Palatal measurements of prematurely born, very low birth weight infants: comparison of three methods.

To enable investigation of palatal changes in infants who are prematurely born, it is necessary to first establish a reliable method of measurement of these tiny edentulous palates. This study compared the Olivetti-Inspector machine, Vernier calipers, and stereophotogrammetry for this purpose. Measurements were taken of 12 palatal casts of four infants at prescribed time intervals during the neonatal period. In each of the three methods, measurements were recorded as variables generated in the X and Z axes of the Cartesian scale in relation to three specified points along the Y axis. The results revealed that all methods were comparable, but the Vernier calipers differed significantly from the other two methods in height measurements, (p < 0.001). It was also found that both the Olivetti-Inspector machine and the Vernier calipers consistently underestimated the width, compared with Olivetti-Inspector machine, (p < 0.05). Stereophotogrammetry was found to be the most consistent method of measuring the configuration of preterm infant palates.

Ischaemic deterioration following aneurysmal subarachnoid haemorrhage: definition by clinical criteria.

Ischaemia following surgery for aneurysmal subarachnoid haemorrhage (SAH) was defined by clinical criteria. Two distinct groups of patient developing ischaemia were identified: (1) patients recovering from anaesthesia with a new deficit or (2) patients developing 'true' delayed ischaemia. The only significant difference between the groups was an excess of pre-existing vascular disease in the former group. The eventual outcome for patients developing an immediate postoperative deficit was not significantly different from the delayed ischaemia group. The 6-month outcome for patients without clinical ischaemia in the first 10 postoperative days was excellent. The potentially different aetiology of ischaemia in the two subgroups with clinical ischaemia identified in this study should be considered during the planning and in particular the statistical design of trials testing new treatments for clinical ischaemia following aneurysmal SAH.

Smoking and subarachnoid haemorrhage: a case control study.

Retrospective and epidemiological studies have suggested that smoking increases the risk of developing aneurysmal subarachnoid haemorrhage (SAH). During 1990, 217 patients presenting to the Mersey Regional Neurosurgical unit with spontaneous SAH were prospectively studied. Smoking habits of patients with SAH were compared with age, sex and occupation matched controls. The relative risk of spontaneous aneurysmal SAH for smokers was twice that of non-smokers (p < 0.001). Management outcome at 6 months following aneurysmal SAH was similar for smokers and non-smokers (p = 0.43) but smokers had more postoperative pulmonary complications requiring ventilation. Significance was tested with chi-square tests.

Dysraphic problems in the lumbar spine: dilemmas in management--a review of 49 cases.

Occult spinal dysraphism can present in many ways. In this review the clinical features, pathology, and management of 49 adult and pediatric cases are discussed. Most recent papers agree that surgery should be performed for clinical deterioration, and many now advise prophylactic surgery for stable or asymptomatic patients. This paper questions the role of prophylactic surgery in such patients. The natural history of occult dysraphism is not known, particularly in the case of adult or asymptomatic patients A conservative management policy, with operation reserved for subsequent clinical or electrophysiological deterioration, is still acceptable in stable or asymptomatic patients. The prospective study of cohorts of patients, with the various forms of occult spinal dysraphism, from units with differing management policies, will help to clarify the natural history of this condition and whether this may be influenced by prophylactic surgery.

Meningiomas presenting with paranasal sinus involvement.

Extracranial paranasal spread of meningiomas is uncommon. We describe the management of four cases, all of which first presented to an oto-rhino-laryngologist for an opinion. We suggest that greater use of modern imaging techniques could lead to earlier diagnosis. The natural history of extracranial spread is relatively benign but the management of regrowth of residual disease is difficult. We therefore suggest radical surgery in the first instance provided that the patients general health and configuration of the tumour allow.

Who shall be served? Issues in screening for emotional and behavioral problems in school.

The major issues involved in the design and implementation of effective school screening programs are addressed, using data from a longitudinal study following over 500 children from preschool through third grade. The article identifies early characteristics of children that are related to later behavioral and emotional problems, assesses the accuracy of a comprehensive screening procedure for identifying such problems, and compares two models using preschool and kindergarten data. Characteristics of children missed by the models are presented, and labeling issues are addressed. Implications for future screening efforts, policy, and research are discussed.

Complement biosynthesis by the human hepatoma-derived cell line HepG2.

The human hepatoma-derived cell line, HepG2, synthesized and secreted functional complement proteins C1r, C1s, C2, C3, C4, C5, factor B, C1 inhibitor, C3b inactivator, a small amount of C6, and trace amounts of C8; but failed to produce detectable C1q, C7, or C9. Immunochemically, C2, C3, C4, C5, and B were isolated from culture medium as proteins with molecular sizes and subunit structures identical to the corresponding components isolated from serum. C2 and factor B from cellular lysates had slightly lower molecular weights than the corresponding proteins in culture medium. C3, C4, and C5 were detected as single chain precursor molecules in cellular lysates. These results demonstrate that human C5, like C3 and C4, is synthesized as a single chain precursor that is converted by limited proteolysis to the native two-chain molecule. It also establishes the precursor-product relationship for human pro-C4 and native C4, pro-C5, and native C5.

Evidence for aqueous soluble vitamin D-like substances in the calcinogenic plant, Tristetum flavescens.

A crude aqueous extract of the leaves of T. flavescens when administered orally to vitamin D-deficient chicks produced significant increases in plasma phosphate but had little effect on plasma calcium. When chicks, fed a high strontium diet to inhibit endogenous 1,25 (OH)2 vitamin D3 production and intestinal calcium transport, were dosed with the extract or synthetic 1,25 (OH)2D345Ca absorption from the duodenum in vivo was stimulated, whereas vitamin D3 was ineffective. Partial purification of the crude extract on a Sephadex GH25 column yielded two factors, one of which mimicked 1,25 (OH)2D3 activity in chicks fed the high strontium diet while the other produced a significant increase in plasma phosphate. The presence of these substances, together with previously demonstrated organic solvent soluble vitamin D-type activity, may account for the calcinogenic nature of the plant.

Biosynthesis and processing of a human precursor complement protein, pro-C3, in a hepatoma-derived cell line.

A 180,000-dalton single-chain molecule (human pro-C3) is the precursor of the third component of human complement (C3), a disulfide-linked two-chain protein. The pro-C3 is converted by limited proteolysis to C3. The relationship between pro-C3 and C3 was established with the use of Hep G2, a cell line derived from a human hepatocellular carcinoma, which synthesizes at least 17 plasma proteins.

Solanum torvum as a causative agent of enzootic calcinosis in Papua, New Guinea.

Inclusion of dried powdered leaves of Solanum torvum Swartz (collected in Papua, New Guinea) in the diet of rats induced hypercalcaemai rapidly and hyperphosphataemia more slowly; soft tissue calcification was most evident in the kidney and lung. Solanum torvum may be a causative agent of enzootic calcinosis in cattle in Papua, New Guinea.

The first component of complement. A quantitative comparison of its biosynthesis in culture by human epithelial and mesenchymal cells.

Epithelial and mesenchymal cells synthesized and secreted all three subcomponents of the first component of complement (C1): C1q, C1r, and C1s. Quantitatively, however, columnar and transitional epithelial cells secreted 400--3,700 times more hemolytically active C1 than monocytes or fibroblasts. Only columnar epithelial cells synthesized C1 subcomponents with subunit structures similar to their serum counterparts. Transitional epithelial cells, fibroblasts, and monocytes produced C1q and C1s with subunits of apparent molecular weights larger than reported values. C1r from all cell lines was physiochemically similar to serum C1r.

The effect on egg-shell thickness of the inclusion of the calcinogenic plant Solanum malacoxylon in the diet of laying hens.

The leaves of the plant Solanum malacoxylon contain 1,25 dihydroxycholecalciferol, the active form of vitamin D. The effect on egg-shell thickness of supplementing the diet of laying hens with a dry powdered preparation of the leaves (DLSM) has been studied. A significnat increase in shell thickness was evident for eggs laid on the second and subsequent days of the DLSM-regimen but nor for those laid during the first 24 hours. It is suggested that the provision of high doses of the vitamin D metabolite in the form of a DLSM supplement may restore calcium binding protein levels in birds approaching the end of the first laying year and hence improve dietary calcium absorption and consequently egg-shell quality.

Quantitative analysis of tryptophan metabolites in urine of normal and endotoxin poisoned mice.

We have developed methods for quantitatively monitoring the in vivo flow of tryptophan between the kynurenine and serotonin pathways. Our data suggest that endotoxin-poisoned mice have more tryptophan flowing into the serotonin pathway than normal mice both with and without tryptophan load. It appears that the distribution of tryptophan between the serotonin and kynurenine pathways in vivo is constant over a very wide dose range and that substrate availability rather than tryptophan oxygenase activity determines the precise amounts of tryptophan which flows into the two pathways.