Circadian Rhythmicity and Photoperiodism in the Pitcher‐Plant Mosquito: Can the Seasonal Timer Evolve Independently of the Circadian Clock?

The two major rhythms of the biosphere are daily and seasonal; the two major adaptations to these rhythms are the circadian clock, mediating daily activities, and the photoperiodic timer, mediating seasonal activities. The mechanistic connection between the circadian clock and the photoperiodic timer remains unresolved. Herein, we show that the rhythmic developmental response to exotic light:dark cycles, usually used to infer a causal connection between the circadian clock and the photoperiodic timer, has evolved independently of the photoperiodic timer in the pitcher-plant mosquito Wyeomyia smithii across the climatic gradient of eastern North America from Florida to Canada and from the coastal plain to the mountains. We conclude that the photoperiodic timing of seasonal events can evolve independently of the daily circadian clock.

Geographic and developmental variation in expression of the circadian rhythm gene, timeless, in the pitcher-plant mosquito, Wyeomyia smithii

Expression of the circadian rhythm gene timeless was investigated in the pitcher-plant mosquito, Wyeomyia smithii (Coq.), and was found to vary with time of day, instar of diapause, and latitude of origin. The temporal pattern of timeless expression differed between the two diapausing instars and was significantly higher in southern (38-40 degrees N) than in northern (50 degrees N) populations, when diapausing instar was held constant. Expression of timeless is therefore both developmentally and evolutionarily variable. This result provides the first example of a latitudinal difference in the expression of timeless, suggesting that, along with evidence from other insects, timeless has the potential to affect photoperiodic response and its adaptive evolution in temperate seasonal environments.

Percutaneous (Portex) tracheostomy: an audit of the Newcastle experience

The purpose of this study was to audit the results of percutaneous tracheostomies performed by ENT surgeons in Newcastle. During a 3-year period, 298 tracheostomies: 196 percutaneous and 102 open were studied. A complication rate for percutaneous tracheostomy was found to be 10% compared to 8% for open, this difference was not statistically significant chi 2 = 0.279, P = 0.598 (DF = 1). The indications for percutaneous tracheostomy were mainly limited to respiratory support for intensive care unit patients, whereas the majority of open tracheostomies were performed in the operating theatre. The results of this audit suggest that percutaneous tracheostomy is the method of choice for respiratory support in the intensive care unit and is as safe as the open technique.

Mutations in btk in patients with presumed X-linked agammaglobulinemia

In 1993, two groups showed that X-linked agammaglobulinemia (XLA) was due to mutations in a tyrosine kinase now called Btk. Most laboratories have been able to detect mutations in Btk in 80%-90% of males with presumed XLA. The remaining patients may have mutations in Btk that are difficult to identify, or they may have defects that are phenotypically similar to XLA but genotypically different. We analyzed 101 families in which affected males were diagnosed as having XLA. Mutations in Btk were identified in 38 of 40 families with more than one affected family member and in 56 of 61 families with sporadic disease. Excluding the patients in whom the marked decrease in B cell numbers characteristic of XLA could not be confirmed by immunofluorescence studies, mutations in Btk were identified in 43 of 46 patients with presumed sporadic XLA. Two of the three remaining patients had defects in other genes required for normal B cell development, and the third patient was unlikely to have XLA, on the basis of results of extensive Btk analysis. Our techniques were unable to identify a mutation in Btk in one male with both a family history and laboratory findings suggestive of XLA. DNA samples from 41 of 49 of the mothers of males with sporadic disease and proven mutations in Btk were positive for the mutation found in their son. In the other 8 families, the mutation appeared to arise in the maternal germ line. In 20 families, haplotype analysis showed that the new mutation originated in the maternal grandfather or great-grandfather. These studies indicate that 90%-95% of males with presumed XLA have mutations in Btk. The other patients are likely to have defects in other genes.

Serum neuron-specific enolase as early predictor of outcome after cardiac arrest

OBJECTIVE

To examine the prognostic value of serum neuron-specific enolase for early prediction of outcome in patients at risk for anoxic encephalopathy after cardiac arrest.

DESIGN

Prospective study.

SETTING

Coronary intensive care unit of the University of Heidelberg.

PATIENTS

Forty-three patients (66.8 +/- 12.7 [SD] yrs, range 33 to 85) who had had either primary or secondary cardiac arrest, followed by cardiopulmonary resuscitation (CPR).

INTERVENTIONS

Serial blood samples and clinical examinations.

MEASUREMENTS AND MAIN RESULTS

Serum neuron-specific enolase concentrations were determined after CPR on 7 consecutive days. Twenty-five patients remained comatose and subsequently died; 18 patients survived the first 3 months and had no relevant functional deficit at 3-month follow-up. Neuron-specific enolase concentrations were correlated with neurologic outcome. Concentrations of >33 ng/mL predicted persistent coma with a high specificity (100%) and a positive predictive value of 100%. Overall sensitivity was 80%, with a negative predictive value of 78%. Serum concentrations of neuron-specific enolase exceeded this cutoff value no more than 3 days after cardiac arrest in 95% of patients in whom these concentrations had exceeded 33 ng/mL.

CONCLUSIONS

In patients who have been resuscitated after cardiac arrest, serum neuron-specific enolase concentrations of >33 ng/mL predict persistent coma with a high specificity. Values below this cutoff level do not necessarily indicate complete recovery, because this method has a sensitivity of 80%.

Cryoglobulinaemia and septal perforation: a rare but logical cause

A case of nasal septal perforation secondary to cryoglobulinaemia is reported. In this instance the cryoglobulinaemia was due to Waldenstrom's macroglobulinaemia (lymphoplasmocytic lymphoma with IgM paraprotein) in which the paraprotein was a potent cryoglobulin.

Interleukin-2, its soluble receptor, and soluble T8 antigen in acute ischemic stroke

The treatment of neoplasia with interleukin-2 (IL-2) can be complicated by neurological deficits resembling transient Ischemic attack and stroke. We investigated whether interleukin-2 contributes to the natural course of cerebrovascular ischemia and particularly to the pathogenesis of infection-associated stroke. Plasma levels of interleukin-2 were below the level of detectability in almost all measurements. Patients with and without previous infection (n = 11, 805 ±445 U/ml vs n = 19, 824 ± 501 U/ml) did not have significantly higher levels of soluble interleukin-2 receptors than control subjects with (n = 14, 667 ± 229 U/ml) or without vascular risk factors (n = 17, 567 ± 176 U/ml). Receptor levels increased in patients during the first week after stroke (n = 15, 1157 ± 1013, p < 0.02). Levels of soluble T8 antigen (sT8) were higher in patients (n - 26, 320 ± 112 U/ml) than in healthy control subjects (n = 15, 246 ± 92 U/ml; p < 0.05) and sT8 levels increased during the first week after stroke (p < 0.05). These results reflect an immunological response to the cerebral infarct; they do not indicate a general role of the IL-2 system in the pathogenesis of ischemic stroke with or without previous infection.

Factors determining the long-term outcome of surgery for acromegaly

Seventy-nine patients with acromegaly were investigated before and after transsphenoidal adenomectomy, to determine the immediate and late outcome, the pre-operative features associated with a good result, and the accuracy of post-operative testing in predicting outcome. Pre-operative evaluation included basal growth hormone (GH), GH response to oral glucose tolerance test (OGTT), GH response to thyrotrophin-releasing hormone (TRH), tests of pituitary reserve, and pituitary scanning to assess tumour size. A few weeks after surgery, these tests were repeated. The patients were recalled for late assessment 1-13 years (median 86 months) after the operation. At the immediate postoperative testing, minimum GH after oral glucose was < or = 2 mU/l in 48.7%, < 5 mU/l in 76.3% and < 10 mU/l in 84.2%. Only 12 patients had GH > 10 mU/l. Basal GH was < or = 2 mU/l in 21%, < 5 in 59.2%, < 10 in 73.6% and < 20 in 90.8%. A minimum GH of < or = 2 mU/l during an OGTT was achieved in 67.4% of patients with intrasellar tumours, compared with 27.3% with extrasellar tumours. Basal GH and post-glucose GH correlated with the late outcome. GH response to TRH showed no correlation with outcome. IGF-1, which could not be assessed in detail, correlated with GH but was not a reliable indicator of outcome. Transsphenoidal adenomectomy is thus a very satisfactory treatment for acromegaly. Postoperative levels of basal growth hormone < 5 mU/l and post-glucose GH < or = 2 mU/l can be regarded as a biochemical cure. Postoperative radiotherapy is not required in patients who achieve a good result. The preoperative factors which significantly influenced the final outcome were basal GH, post-glucose minimum GH, tumour size and impaired pituitary reserve.

[Autologous transfusion--organization and results of preoperative blood donation by heart surgery patients]

This study presents our preoperative autologous blood donation programme that is in use since 1987. 246 patients of cardiothoracic surgery participated in this program. 77% of all patients had preoperative concentrations of haemoglobin above 12g/dl despite frequent donations. 36.5% of patients were transfused exclusively with their own blood products. Reduction of homologous blood transfusion has been achieved with second preoperative plasmaphereses and more restricted indication for blood transfusion. More blood donation could be performed with application of erythropoietin resulting in more frequent preoperative blood donations.

[Transfusion-induced Yersinia infection]

After a primary operation for renal artery stenosis a 48-year-old woman had to be re-operated twice for renewed arterial stenosis and retroperitoneal bleeding. The patient's respiratory and cardiovascular functions were stable two days after the second operation and renal function was recovering. But because of suspected renewed bleeding a transfusion with erythrocyte concentrate was begun. Fifteen minutes later the patient started to shiver and this was followed by signs of cardiocirculatory decompensation under the picture of a septic-toxic shock. Laboratory tests did not indicate a haemolytic transfusion reaction. Controlled mechanical ventilation and circulatory drug support were required over the next two days, renewed anuria persisting for longer than a week. Microbiological tests of the erythrocyte concentrate demonstrated Yersinia enterocolitica, serotype 03. Questioning of the blood donor revealed a mild gastroenteritis at the time of donation. This case underlines the need of excluding donors, if only temporarily, when there is even slight suspicion of a Yersinia infection.

LH and FSH secretion and responses to GnRH and TRH in patients with clinically functionless pituitary adenomas

Serum concentrations of LH and FSH and their response to the separate administration of GnRH (100 micrograms i.v.) and TRH (200 micrograms i.v.) have been studied preoperatively in 12 patients with a clinically functionless pituitary adenoma, of whom nine (3F: 6M) were found to secrete gonadotrophins in vitro. In three patients with a gonadotrophin-secreting adenoma (GSA) the pulsatile release of LH and FSH was also assessed preoperatively. An elevated serum FSH was recorded in six of nine patients with a GSA, and was subnormal in one, whilst an elevated LH was recorded in only two and was subnormal in six. A doubling of LH occurred in only four of the nine patients after GnRH and in three of six after TRH. None of the three patients with a non-GSA was shown to have an aberrant response to GnRH or TRH. In patients with a GSA, pulsatile release of LH and FSH was usually asynchronous and neither hormone demonstrated any regular harmonic pattern. These data show that in patients with a GSA the serum FSH level is usually elevated but this is not invariable, and the LH may well be low. Pathological responses of LH are frequently found following the administration of either GnRH or TRH and these stimulation tests should be performed separately in patients presenting with a clinically 'non-functioning' pituitary tumour to assist in the preoperative diagnosis. The absence of normal LH and FSH pulsing also appears to be a feature of GS adenomas, and suggests that tumorous gonadotrophin secretion is not under physiological control by hypothalamic GnRH.

Immunoradiometric assay of carcinoembryonic antigen with use of avidin-biotin labeling

In evaluating an enzyme-linked immunoassay of carcinoembryonic antigen (CEA) we found that the IgG fraction of polyclonal anti-CEA antibodies (DAKO) bound very well to the walls of polypropylene test tubes. We therefore developed an immunoradiometric CEA assay based on this binding of polyclonal anti-CEA antibody. We biotinylated a commercially available monoclonal antibody (Hybritech) and bound this to the CEA-anti-CEA bound to the tube wall. For detection we used 125I-labeled streptavidin. In comparison with several immunoassays for CEA this system offered several advantages such as greater linearity of the standard curve (from 0 to 74 micrograms/L), a steeper dose-response curve, and smaller coefficients of variation in the clinically useful range. This assay system may be used for other large molecules, so that only one tracer, the 125I-labeled streptavidin, has to be labeled; thus the technique seems suited for several different assays.

Immunoradiometric assay of carcinoembryonic antigen with use of avidin-biotin labeling

In evaluating an enzyme-linked immunoassay of carcinoembryonic antigen (CEA) we found that the IgG fraction of polyclonal anti-CEA antibodies (DAKO) bound very well to the walls of polypropylene test tubes. We therefore developed an immunoradiometric CEA assay based on this binding of polyclonal anti-CEA antibody. We biotinylated a commercially available monoclonal antibody (Hybritech) and bound this to the CEA-anti-CEA bound to the tube wall. For detection we used 125I-labeled streptavidin. In comparison with several immunoassays for CEA this system offered several advantages such as greater linearity of the standard curve (from 0 to 74 micrograms/L), a steeper dose-response curve, and smaller coefficients of variation in the clinically useful range. This assay system may be used for other large molecules, so that only one tracer, the 125I-labeled streptavidin, has to be labeled; thus the technique seems suited for several different assays.

[Possible interfering factors in the screening of newborn infants for inborn errors of metabolism and measures for their prevention]

From taking a sample to communicating the result, the success of neonatal screening is endangered by a series of pitfalls. Besides internal and external quality control and an adequate practical experience due to high sample throughput, it is important to know these possibilities of errors in order to be able to reduce them to a minimum in daily routine work.

Clinical significance and source of raised catalytic activities of phosphohexose isomerase in the CSF in meningitis

The value of phosphohexose isomerase (EC 5.3.1.9) determination in the CSF in the diagnosis of meningitis was tested under routine conditions. In 48 patients with untreated bacterial meningitis, enzyme activity concentrations between 40 and 2335 U/l were measured, whereas the highest phosphohexose isomerase activity concentration in 92 patients with viral meningitis was 34 U/l. Lysis of the CSF leukocytes with Triton X-100 resulted in a substantial increase of phosphohexose isomerase activity. In bacterial meningitis these values increased to 200 to 7000 U/l, but remained under 150 U/l in viral meningitis. The raised enzyme activities are derived from the leukocytes and appear to reflect their functional and metabolic state. The information provided by the leukocyte morphology can thus be appreciably extended by phosphohexose isomerase determination.

Follow-up study of 16 years neonatal screening for inborn errors of metabolism in West Germany

Capillary blood samples from almost one million neonates from Baden-Württemberg were investigated for inborn errors of metabolism between 1969 and 1984 in our screening centre. Besides 7 patients with maple syrup urine disease (MSUD), 3 with homocystinuria and 18 with galactosaemia, a follow-up of the positive screening results confirmed 94 patients with phenylketonuria (PKU) and 76 with non-PKU hyperphenylalaninaemia (non-PKU HPA). The incidence of PKU is 1:10000, and that of HPA in the wider sense (PKU and non-PKU HPA) as obtained by newborn screening before further classification at 6 months 1:5532. For West Germany as a whole, the number of newly discovered cases with persistent hyperphenylalaninaemia was 1480 in the same period. The subdivision into PKU and non-PKU HPA is not yet possible from this figure. It is strongly suggested that the abnormal results of newborn screening for phenylalanine be designated as hyperphenylalaninaemia (in the wider sense) and that the terms "PKU" or "non-PKU HPA" be used only after further differentiation as carried out by us at the age of 6 months.

Growth hormone secreting pituitary adenomas are heterogeneous in cell culture and commonly secrete glycoprotein hormone alpha-subunit

Cell culture methods were used to assess whether human pituitary adenomas secreting GH and associated with clinical acromegaly also secreted the structurally unrelated glycoprotein hormone alpha-subunit. Thirty-two tumours, together with peri-adenomatous tissue from two of them and three normal pituitaries were studied. Anterior pituitary hormones were measured by radioimmunoassay and included PRL, TSH, LH, FSH, and ACTH, as well as GH and alpha-subunit. Normal pituitary tissues secreted all hormones assayed. All 32 tumours secreted GH ranging from 241 to 5556 ng/2 X 10(5) cells/24 h and 12 (37.5%) secreted alpha-subunit in amounts which could not be accounted for by cross-reaction of other hormones or contamination by normal pituitary tissue, and which ranged from 10.3 to 73.5 ng/2 X 10(5) cells/24 h. Ten other tumours also secreted alpha-subunit but in very small amounts, not exceeding 1.8 ng/2 X 10(5) cells/24 h. PRL was secreted from 21 tumours (66%), and small amounts of other hormones, chiefly LH and TSH, were occasionally secreted from tumours. These cell culture studies would suggest that pituitary adenomas causing acromegaly are hormonally heterogeneous and that PRL and glycoprotein alpha-subunit are commonly detected in addition to GH.

Inter-laboratory quality control in neonatal screening for inborn errors of metabolism

Screening of neonates for inborn errors of metabolism has been carried out on a national level since 1969 in the Federal Republic of Germany. To raise the reliability of these routine investigations, we introduced an external quality control in March 1982. Every 2 months ten filter paper samples were sent to the screening centres in West Germany. Some of these samples have a normal and others a slightly raised content of phenylalanine, leucine, methionine and galactose. The success of this external quality control is appraised on the basis of the number of false negative results. In the course of time, screening centres in France, Israel, Italy, Japan, Switzerland, Taiwan, Turkey and Yugoslavia have also participated in these inter-laboratory quality controls.

Effects of growth hormone-releasing factor (1-44) on growth hormone release from human somatotrophinomas in vitro: interaction with somatostatin, dopamine, vasoactive intestinal peptide and cycloheximide

The effect of GH-releasing factor(1-44)(GRF) alone, or together with somatostatin (SRIF), dopamine (DA), vasoactive intestinal peptide (VIP) or cycloheximide was studied in a total of ten human somatotrophinomas using a static cell culture system. Growth hormone-releasing factor (2.0 X 10(-8) mol/l) significantly (P less than 0.05) stimulated GH release from nine out of ten tumours over 4-h incubations, and a dose-related effect (2.0 X 10(-10) -2.0 X 10(-8) mol/l) was observed in five tumours thus studied. Repeated GRF (2.0 X 10(-8) mol/l)-mediated GH release was seen during 96% (n = 25) of experiments performed on six tumours over 4 h and up to 27 days in culture. Growth hormone-releasing factor (2.0 X 10(-8) mol/l) also stimulated GH release from five out of seven somatotrophinomas during 60-min incubations. Somatostatin (6.1 X 10(-9) mol/l) completely inhibited GRF-induced GH secretion from four tumours studied over 4 h, but in each case there was significant (P less than 0.05) 'rebound' of GH release from cultures exposed to both GRF and SRIF during a subsequent recovery period. Dopamine suppressed basal GH release from two out of four tumours, but in each case had a greater inhibitory effect on GRF-mediated GH release. Vasoactive intestinal peptide directly stimulated GH release from two out of three tumours, and the effects were additive to maximal stimulatory doses of GRF. Cycloheximide significantly (P less than 0.01) enhanced GRF-stimulated release of GH during a 60-min incubation, but inhibited both basal and GRF-stimulated release over 4 and 8 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholesterol determination in serum after fractionation of lipoproteins by immunoprecipitation

We investigated the immunoprecipitation of apolipoprotein B-binding lipoproteins, or of apo A-I- and apo C-binding lipoproteins, by delipidated antiserum for measuring cholesterol in the nonprecipitated lipoprotein fractions. After immunoprecipitation of serum with delipidated anti-apo B, we determined by immunoelectrophoresis that no beta- or pre-beta lipoproteins were present, whereas alpha-lipoproteins remained in the supernate. Conversely, after immunoprecipitation with an antiserum against apo A-I + apo C, only lipoproteins with beta-mobility were detected and no apo B from beta-lipoproteins was in the precipitate. The concentration of cholesterol in the supernate after immunoprecipitation with anti-apo B correlated highly (r = 0.93, n = 118) with cholesterol measured after precipitation with phosphotungstic acid/MgCl2. The cholesterol concentration after immunoprecipitation with anti-apo AI and anti-apo C correlated similarly well (r = 0.94, n = 145) with the LDL-cholesterol calculated by Friedewald's formula in serum specimens reflecting moderate hyperlipoproteinemia.

Cholesterol determination in serum after fractionation of lipoproteins by immunoprecipitation

We investigated the immunoprecipitation of apolipoprotein B-binding lipoproteins, or of apo A-I- and apo C-binding lipoproteins, by delipidated antiserum for measuring cholesterol in the nonprecipitated lipoprotein fractions. After immunoprecipitation of serum with delipidated anti-apo B, we determined by immunoelectrophoresis that no beta- or pre-beta lipoproteins were present, whereas alpha-lipoproteins remained in the supernate. Conversely, after immunoprecipitation with an antiserum against apo A-I + apo C, only lipoproteins with beta-mobility were detected and no apo B from beta-lipoproteins was in the precipitate. The concentration of cholesterol in the supernate after immunoprecipitation with anti-apo B correlated highly (r = 0.93, n = 118) with cholesterol measured after precipitation with phosphotungstic acid/MgCl2. The cholesterol concentration after immunoprecipitation with anti-apo AI and anti-apo C correlated similarly well (r = 0.94, n = 145) with the LDL-cholesterol calculated by Friedewald's formula in serum specimens reflecting moderate hyperlipoproteinemia.

Phosphohexose isomerase in cerebrospinal fluid in meningitis

The diagnostic value of determining phosphohexose isomerase (PHI, E.C. 5.3.1.9) activity in the CSF for differential diagnosis of bacterial and viral meningitis was investigated. In 29 patients with untreated bacterial meningitis, a mean enzyme activity of 511 U/1 was found, whereas a value 19 U/1 was found in 61 cases of viral meningitis. The reference range with an upper limit of 6 U/1 was determined from CSF samples from 163 "healthy" children. The high diagnostic sensitivity and specificity of 100% and 99.5% respectively make PHI a sensitive differential diagnostic parameter in meningitis.

Skin and homograft cartilage reconstruction

Conservative vertical hemilaryngectomy poses the problem of relating the need to remove the tumor completely to the aim of reconstructing an adequate airway lined with epithelium. An attempt has has been made in experimental animals to overcome this problem using pedicled skin and homograft cartilage. The findings suggest that this is a feasible technique, although somewhat hampered by problems unique to the animals concerned. The use of skin pedicles provides adequate cover without shrinkage, and although it is doubtful whether cartilage can survive intact in the long-term, it would seem that it may be adequate for the purposes intended.