Dopamine and sensory tissue development inDrosophila melanogaster

Dopamine is an important signaling molecule in the nervous system; it also plays a vital role in the development of diverse non-neuronal tissues in the fruit fly Drosophila melanogaster. The current study demonstrates that males depleted of dopamine as third instar larvae (via inhibition of the biosynthetic enzyme tyrosine hydroxylase) demonstrated abnormalities in courtship behavior as adults. These defects were suggestive of abnormalities in sensory perception and/or processing. Electroretinograms (ERGs) of eyes from adults depleted of dopamine for 1 day as third instar larvae revealed diminished or absent on- and off-transients. These sensory defects were rescued by the addition of L-DOPA in conjunction with tyrosine hydroxylase inhibition during the larval stage. Depletion of dopamine in the first or second larval instar was lethal, but this was not due to a general inhibition of proliferative cells. To establish that dopamine was synthesized in tissues destined to become part of the adult sensory apparatus, transgenic lines were generated containing 1 or 4 kb of 5' upstream sequences from the Drosophila tyrosine hydroxylase gene (DTH) fused to the E. coli beta-galactosidase reporter. The DTH promoters directed expression of the reporter gene in discrete and consistent patterns within the imaginal discs, in addition to the expected expression in gonadal, brain, and cuticular tissues. The beta-galactosidase expression colocalized with tyrosine hydroxylase protein. These results are consistent with a developmental requirement for dopamine in the normal physiology of adult sensory tissues.

Pneumococcal pneumonia in patients requiring hospitalization: effects of bacteremia and HIV seropositivity on radiographic appearance

OBJECTIVE

Our purpose was to establish the incidence of lobar versus bronchopneumonia patterns in patients hospitalized for pneumococcal pneumonia and to determine whether bacteremia or HIV status affects the radiographic appearance.

MATERIALS AND METHODS

Eighty-one patients with community-acquired pneumococcal pneumonia and positive findings on admission chest radiographs were selected from a group of 105 patients with positive findings for Streptococcus pneumoniae from sputum or blood cultures. Patients less than 16 years old and those with nosocomial pneumonia, aspiration pneumonia, or coexistent lung disease were excluded. The dominant pattern was classified as lobar or lobular bronchopneumonia by two radiologists who were unaware of results from blood cultures and HIV testing.

RESULTS

Forty-three females and 38 males, with a mean age of 48 years (age range, 16-92 years), required admission for pneumococcal pneumonia. Fifty-nine (73%) of the 81 patients were bacteremic and 20 (25%) of the 81 patients were HIV-positive, including 14 patients (17%) who were both bacteremic and HIV-positive. Among all the patients, focal lobar consolidation was the most common pattern, observed in 48%. Multifocal lobar consolidation was the next most frequent pattern, occurring in 33%. Multifocal and focal bronchopneumonia patterns were seen in 16% and 2% of the patients, respectively. Overall, multifocal consolidation occurred in 49%. The dominant radiographic pattern and incidence of multicentric disease were not affected by HIV seropositivity (p = 0. 61) or bacteremia (p = 0.17).

CONCLUSION

Lobar consolidation, involving single or multiple lobes, is the most common radiographic pattern of community-acquired pneumococcal pneumonia in patients requiring hospitalization. The pattern of consolidation is not influenced by bacteremia or HIV status.

Human umbilical vein endothelial cells differ from other endothelial cells in failing to express ABO blood group antigens

Most in vitro investigations of endothelial cell function have been based on the behaviour of human umbilical vein endothelial cells (HUVEC) in primary tissue culture. However, it is becoming apparent that there is a marked degree of heterogeneity among endothelial cells derived from different vascular beds. We have studied primary HUVEC from 45 umbilical cords. Contrary to previously published reports, we were unable to detect ABO antigens on the surface of cultured HUVEC from group A or B cords. This was not due to an absence of precursor H substance which was uniformly expressed on HUVEC in primary tissue culture. Further investigation revealed an absence of A enzyme activity in A type HUVEC and a level of mRNA only just detectable by RT-PCR. The absence of functional A enzyme activity was confirmed by demonstrating the absence of A substance on von Willebrand factor secreted by A type cells. HUVEC appear to be the only vascular endothelial cells that do not express ABO blood group antigens. We speculate that this may help protect the cord from maternal antibodies during gestation. The lack of ABO blood group antigens on HUVEC may significantly affect their surface function, and therefore care should be taken when extrapolating conclusions from results obtained with these cells (the most widely used human endothelial cell model in vitro) to the properties of adult endothelial cells.

Coronary angioplasty and stenting in orthotopic heart transplants: a fruitful act or a futile attempt?

Accelerated allograft coronary artery disease remains the major cause of mortality after the first year of transplantation. Despite the extensive use of stents and angioplasty in coronary artery disease, there is a paucity of data about the efficacy of such interventions in orthotopic heart transplants. The authors herein report the outcome of those patients in their institution who had undergone percutaneous coronary artery angioplasty and stenting at a late stage of their transplantation. Within a 12-year period, 106 adult patients underwent orthotopic heart transplantation at their institution. Eight of these patients with 17 lesions underwent deployment of nine stents and eight angioplasties 8.1 +/- 3.2 years posttransplantation. There were 15 denovo and two restenotic lesions. The indications for intervention were presence of symptoms in five patients and severity of lesions in three asymptomatic patients detected on their follow-up angiogram. All patients had angiographic worsening of lesions at their follow-up angiogram. The initial procedural success for both stented and angioplastied lesions was 100%. Within a mean angiographic follow-up of 261 days, all balloon angioplastied lesions had developed restenosis, whereas within a mean period of 67 days, 50% of stented lesions had developed restenosis. On the follow-up angiogram, deterioration of the nontreated segments were noted throughout the coronary arterial tree; however, the immediate proximal and distal parts of the target segments demonstrated an exaggerated hyperproliferative response as compared to other sites. The overall median time to the detection of restenosis for both stented and angioplastied lesions was 5.2 months (inner quartile 2.5-6.2 months). The authors conclude that angioplasty and stenting late in the course of transplantation is associated with a significant restenosis rate and in such patients earlier or alternative catheter-based interventions must be considered.

Nodal quasiparticle lifetime in the superconducting state of Bi(2)Sr(2)CaCu(2)O(8+delta)

We have measured the complex conductivity sigma of a Bi(2)Sr(2)CaCu(2)O(8+delta) thin film between 0.2 and 0.8 THz. We find sigma in the superconducting state to be well described as the sum of contributions from quasiparticles, condensate, and order parameter fluctuations which draw 30% of the spectral weight from the condensate. An analysis based on this decomposition yields a quasiparticle scattering rate on the order of k(B)T/Planck's over 2pi for temperatures below T(c).

Bleeding symptoms and coagulation abnormalities in 337 patients with AL-amyloidosis

Haemorrhage is a frequent manifestation of amyloidosis. We performed a retrospective clinical analysis of 337 patients with systemic immunoglobulin light-chain (AL)-amyloidosis, in whom whole-body serum amyloid P component (SAP) scintigraphy and a clotting screen had been performed. Abnormal bleeding was noted in 94 cases (28%), and the coagulation screen was abnormal in 172 cases (51%). The most common abnormalities were prolongation of the thrombin time (TT; 108 cases, 32%) and the prothrombin time (PT; 82 cases, 24%). In multivariate analysis, a prolonged PT was the only coagulation abnormality associated with abnormal bleeding (P = 0.0012), but this was independent of the whole-body amyloid load. Prolongation of the TT was associated with hepatic amyloid infiltration (P < 0.00001), with proteinuria (P < 0.001) and low serum albumin (P < 0.00001). In 154 patients who were studied further, subnormal factor X activity (FX:C) was found in 22 cases (14%). In cases with subnormal FX:C, the corresponding factor X antigen (FX:Ag) measurements were consistently higher (median FX:Ag/FX:C 2.5, range 0.81-9.25, n = 16) than cases with normal FX:C (median FX:Ag/FX:C 0.96, range 0.65-1.29, n = 28, P < 0.0001). No evidence was found of an FX inhibitor. Of the 48/154 (31%) cases with a prolonged TT, the reptilase time was also prolonged in 38/48 cases (79%). These data show that haemorrhage and abnormal coagulation are common in AL-amyloidosis and are multifactorial in origin. We provide evidence suggesting that hepatic amyloid infiltration and nephrotic syndrome are determinants of the TT. In most patients, prolongation of the PT was explained by reduction in FX:C, but this was not wholly explained by a reduction in FX:Ag.

HLA-B27 associated spondyloarthropathy and severe ascending aortitis

We describe a young woman who developed early and severe aortic regurgitation and subsequent aortitis with aneurysm formation requiring surgery.

Signature of superfluid density in the single-particle excitation spectrum of Bi(2)Sr(2)CaCu(2)O(8+delta)

We report that the doping and temperature dependence of photoemission spectra near the Brillouin zone boundary of Bi(2)Sr(2)CaCu(2)O(8+delta)exhibit unexpected sensitivity to the superfluid density. In the superconducting state, the photoemission peak intensity as a function of doping scales with the superfluid density and the condensation energy. As a function of temperature, the peak intensity shows an abrupt behavior near the superconducting phase transition temperature where phase coherence sets in, rather than near the temperature where the gap opens. This anomalous manifestation of collective effects in single-particle spectroscopy raises important questions concerning the mechanism of high-temperature superconductivity.

Stimulus control and generalization of point-loss punishment with humans

Two experiments demonstrated stimulus control and generalization of conditioned punishment with humans. In both studies, responses first were reinforced with points exchangeable for money on a variable-interval schedule in the presence of one line length (S(D)). Next, a second line length was introduced, and point loss followed every response in the presence of that line (S(D)p). In the final training condition, points were deducted at session end. Response rate was lower in the presence of the S(D)p despite equal rates of points for money in the presence of both stimuli. In generalization testing for Experiment 1, the two lines were included in a 10-line continuum; S(D)p fell in the middle and the trained SD was at one end. Lines were presented randomly, and point delivery and loss contingencies were as in training but with points available in the presence of all lines. For all subjects, response rates were lowest around S(D)p and increased towards the SD end of the continuum. Because testing included only one or two lines beyond S(D), this pattern did not rule out S(D) generalization. Thus, in Experiment 2, stimuli beyond S(D) were added to generalization tests. Response rates did not decrease as a function of distance from S(D), clarifying the demonstration of punishment generalization.

Mesoscopic thermodynamics of an inhomogeneous colossal-magnetoresistive phase

Equilibrium conductivity fluctuations of mesoscopic domains are found in film and bulk single-crystal manganite colossal magnetoresistive material. Temperature and field dependences of the Boltzmann factors for a collection of two-state fluctuators give measures of the magnetic moment and entropy differences between the states, and of the fluctuator volumes. The large resistance step size implies dramatic current inhomogeneities. Occasional anomalous temperature dependences indicate that the film inhomogeneous phase is stabilized by a repulsive interaction between conducting regions.

Functional interactions between GTP cyclohydrolase I and tyrosine hydroxylase in Drosophila

Tyrosine hydroxylase requires the regulatory cofactor, tetrahydrobiopterin, for catecholamine biosynthesis. Because guanosine triphosphate cyclohydrolase I is the rate limiting enzyme for the synthesis of this cofactor, it has a key role in catecholamine production. We show that GTP cyclohydrolase and tyrosine hydroxylase (TH) are co-localized in the Drosophila central nervous system. Mutations in the Punch locus, which encodes GTP cyclohydrolase, reduce TH activity; addition of cofactor to crude extracts could not fully rescue this activity in all mutant strains. The decrease in TH activity and the inability to increase it with added cofactor is not due to loss or decreased production of TH protein. We found that TH co-immunoprecipitated with GTP cyclohydrolase when wild type head extracts were incubated with anti-GTP cyclohydrolase antibody. We suggest that regulation of TH by its cofactor may require its association with GTP cyclohydrolase, and that the ability of GTP cyclohydrolase to associate with TH and its role in tetrahydrobiopterin synthesis may be separable functions of this enzyme. These results have important implications for understanding catecholamine-related neural diseases and designing strategies for gene therapy.

Elevation of FVIII: C in venous thromboembolism is persistent and independent of the acute phase response

Recent literature has suggested a role for elevated FVIII:C in venous thromboembolic disease (VTED). However since FVIII:C is known to rise in response to an acute phase reaction, it is difficult to determine whether the increased FVIII:C precedes the thrombosis or represents a secondary reactive phenomenon. In an attempt to address this question, we followed 35 patients with confirmed VTED, raised FVIII:C level (>1.5 iu/ml) and no other thrombotic tendency. Serial measurements of FVIII:C, vWF:Ag, C-reactive protein and fibrinogen were performed. We hypothesized that a persistent increase in FVIII:C in the absence of any other measures of ongoing acute phase response, would support the idea that elevation of FVIII:C is a constitutional phenomenon. Of this initial group, 94% continued to have an elevated FVIII:C level throughout the period of follow up (median 8 months; range 3 to 39 months), with no significant difference between the FVIII:C levels determined at first estimation and those obtained during follow up (p = 0.58). Conversely, only 18% had evidence of an acute phase reaction when first assessed, and nonparametric ranking analysis demonstrated no correlation between FVIII:C and either C-reactive protein or fibrinogen (p = 0.315 and 0.425 respectively).We conclude that increased FVIII:C levels following VTED are persistent, independent of the acute phase reaction, and thus may represent a constitutional risk factor for VTED.

Injury analyses of fatal motorcycle collisions in south-east Scotland

The timing of death and pathological findings in fatal motorcycle accidents in south-east Scotland between 1987 and 1997 were investigated. Of the 59 motorcyclists who died, 38 were dead when found at the accident scene, six others were alive when found but died at the scene, two died in an ambulance in transit to hospital and 13 died after reaching hospital. Scoring of the injuries according to the Abbreviated Injury Scale revealed Injury Severity Scores (ISS) ranging from 25 to 75. Overall, injuries to the head, neck and chest were responsible for the most severe injuries. Twenty-five motorcyclists had injuries acknowledged to be unsurvivable (ISS = 75), most of which involved the thoracic aorta, brainstem and cervical spinal cord. The greatest potential to reduce the death rate amongst motorcyclists lies with accident prevention/injury reduction measures, rather than through improved treatment of injuries. Efforts to try to alter driving behaviour and to improve the design of vehicles and helmets need to continue.

Metabolism of pamaqueside, a cholesterol absorption inhibitor, in Long-Evans rat: effect of bile duct cannulation on absorption

The metabolism of pamaqueside, a cholesterol absorption inhibitor, was studied in the bile duct cannulated and non-cannulated rat after an oral dose (100 mg/kg) and an i.v. dose (6 mg/kg) of [14C]pamaqueside. Faeces was the major route of excretion in all rat. Only 0.1% of the radioactivity was recovered in the urine of the non-cannulated rat. In contrast, approximately 17% of the total dose was recovered in the bile and urine in the bile duct cannulated rat. Following an i.v. dose, an almost equal percentage of radioactivity was excreted in the bile and urine of the bile duct cannulated rat. 3. The aglycone (M1) was the major metabolite in rat and was present in greater amounts in the faeces of the bile duct cannulated rat. The structural elucidation of metabolites in the bile and urine indicated that M1 was metabolized oxidatively via a novel ring opening, and the oxidative metabolites further underwent sulphate conjugation. The oxidative ring opening of pamaqueside (the cellobioside ring intact) was also observed following an i.v. dose to rat suggesting that oxidative ring opening was the major route of metabolism of saponins, at least in rat. The study demonstrated that the absorption and metabolism of pamaqueside was altered by surgical cannulation of rat.

On-farm quality assurance programs: a survey of producer and industry leader opinions

To assess interest in implementing a California dairy quality assurance program, practices and opinions of dairy producers and industry leaders were surveyed by a mailed questionnaire and by focus groups. The majority of the 55 participants in the focus group were dairy producers; processor marketing executives, extension dairy advisors, packinghouse executives, and dairy veterinarians were represented. The consensus among the focus groups was that a quality assurance program should be voluntary, be managed by creameries, and confer an economic advantage to participants. Focus group members listed chemical and microbial food safety (in both meat and milk), environmental health, and animal welfare as issues that should be addressed. Of the 1440 questionnaires mailed with producers' milk checks, 413 were returned. Information was collected regarding opinions and practices pertaining to administration of drugs to animals, medical records and animal identification, culling practices, manure management, cow welfare, and feeding of animal protein. An overwhelming 99% of producers believed they were responsible for the safety of meat and milk leaving the farm. Sixty percent of producers said that they would consider joining a California-specific quality assurance program, whereas 9% indicated that they would not. Producers would be more likely to join if their processor believed it would impart a market advantage and if the program standards were controlled by producers.

Patients' attitudes to medical students in the accident and emergency department

The objective of this study was to assess patients' attitudes towards medical students in the accident and emergency department. Patients attending a university department of accident and emergency were given a questionnaire asking about their attitudes to medical students. Ninety-three per cent of the patients would not object to being seen and examined by a medical student in the accident and emergency department. No patients reported feeling pressurized to accept this proposal. It is concluded that most patients attending the emergency department had favourable attitudes towards medical students.

Dropped hallux after the intramedullary nailing of tibial fractures

We made a prospective study of 208 patients with tibial fractures treated by reamed intramedullary nailing. Of these, 11 (5.3%) developed dysfunction of the peroneal nerve with no evidence of a compartment syndrome. The patients with this complication were significantly younger (mean age 25.6 years) and most had closed fractures of the forced-varus type with relatively minor soft-tissue damage. The fibula was intact in three, fractured in the distal or middle third in seven, with only one fracture in the proximal third. Eight of the 11 patients showed a 'dropped hallux' syndrome, with weakness of extensor hallucis longus and numbness in the first web space, but no clinical involvement of extensor digitorum longus or tibialis anterior. This was confirmed by nerve-conduction studies in three of the eight patients. There was good recovery of muscle function within three to four months in all cases, but after one year three patients still had some residual tightness of extensor hallucis longus, and two some numbness in the first web space. No patient required further treatment.

Incorporating palliative care into primary care education. National Consensus Conference on Medical Education for Care Near the End of Life

The confluence of enhanced attention to primary care and palliative care education presents educators with an opportunity to improve both (as well as patient care) through integrated teaching. Improvements in palliative care education will have benefits for dying patients and their families, but will also extend to the care of many other primary care patients, including geriatric patients and those with chronic illnesses, who make up a large proportion of the adult primary care population. In addition, caring for the dying, and teaching others to carry out this task, can be an important vehicle for personal and professional growth and development for both students and their teachers.

Changing teaching practices to promote achievement and bonding to school

An intervention to modify teaching practices in grades five and six was evaluated. Results showed that higher levels of teacher implementation of the modified practices favorably influenced students' levels of classroom opportunity, involvement, reinforcement, and bonding to school. Levels of academic achievement were also increased. The importance of assessing implementation in theory-guided experimental studies is discussed.

Exercise-induced rhabdomyolysis

We describe the case of a previously well 55-year-old man who presented to the accident and emergency department with marked swelling of both forearms 6 days after being pulled at speed on a 'fun ride' by a speedboat whilst holding on to a rubber dinghy. Immediately after the event he had marked weakness of both arms lasting 2 days and this was followed by swelling of his forearms. The patient had also noticed a darkening of his urine during this period. On examination there was marked pitting oedema of both forearms. Neurovascular examination of both arms was normal. Laboratory investigations revealed a grossly elevated serum creatinine kinase at 4969 IU/l, with normal urea and electrolyte levels. Urine dipstick testing was also normal at the time of presentation. The patient was discharged home and made an uneventful recovery. We describe the pathophysiology of exercise-induced rhabdomyolysis and discuss its clinical presentation and management.

Avoidance of 20% carbon dioxide-enriched air with humans

Four college students were exposed to a Sidman avoidance procedure to determine if an avoidance contingency involving 20% carbon dioxide-enriched air (CO2) would produce and maintain responding. In Phase 1, two conditions (contingent and noncontingent) were conducted each day. These conditions were distinguished by the presence or absence of a blue or green box on a computer screen. In the contingent condition, CO2 presentation were delivered every 3 s unless a subject pulled a plunger. Each plunger pull postponed CO2 presentations for 10 s. In the noncontingent condition, CO2 presentations occurred on the average of every 5 min independent of responding. Following stable responding in Phase 1, condition-correlated stimuli were reversed. In both conditions, plunger response rate was high during the contingent condition and low or zero during the noncontingent condition. Furthermore, subjects avoided most CO2 presentations. However, CO2 presentations did not increase verbal reports of fear. Overall, the results from the present study suggest that CO2 can be used effectively in basic studies of aversive control and in laboratory analogues of response patterns commonly referred to as anxiety.