Sub-Kelvin cooling for two kilopixel bolometer arrays in the PIPER receiver

The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne telescope mission to search for inflationary gravitational waves from the early universe. PIPER employs two 32 × 40 arrays of superconducting transition-edge sensors, which operate at 100 mK. An open bucket Dewar of liquid helium maintains the receiver and telescope optics at 1.7 K. We describe the thermal design of the receiver and sub-Kelvin cooling with a continuous adiabatic demagnetization refrigerator (CADR). The CADR operates between 70 and 130 mK and provides ≈10 μW cooling power at 100 mK, nearly five times the loading of the two detector assemblies. We describe electronics and software to robustly control the CADR, overall CADR performance in flightlike integrated receiver testing, and practical considerations for implementation in the balloon float environment.

Large-aperture wide-bandwidth antireflection-coated silicon lenses for millimeter wavelengths

The increasing scale of cryogenic detector arrays for submillimeter and millimeter wavelength astrophysics has led to the need for large aperture, high index of refraction, low loss, cryogenic refracting optics. Silicon with n=3.4, low loss, and high thermal conductivity is a nearly optimal material for these purposes but requires an antireflection (AR) coating with broad bandwidth, low loss, low reflectance, and a matched coefficient of thermal expansion. We present an AR coating for curved silicon optics comprised of subwavelength features cut into the lens surface with a custom three-axis silicon dicing saw. These features constitute a metamaterial that behaves as a simple dielectric coating. We have fabricated silicon lenses as large as 33.4 cm in diameter with micromachined layers optimized for use between 125 and 165 GHz. Our design reduces average reflections to a few tenths of a percent for angles of incidence up to 30° with low cross polarization. We describe the design, tolerance, manufacture, and measurements of these coatings and present measurements of the optical properties of silicon at millimeter wavelengths at cryogenic and room temperatures. This coating and lens fabrication approach is applicable from centimeter to submillimeter wavelengths and can be used to fabricate coatings with greater than octave bandwidth.

Pethidine and skin warming to prevent shivering during endovascular cooling

We tested the efficacy of pethidine and cutaneous warming to prevent shivering during percutaneous cooling in unanaesthetized patients. Ten patients scheduled for cranial neurosurgery received pethidine infusion and skin warming. The Setpoint internal heat-exchanging catheter was inserted and cooling to 33.5 degrees C was started. Clonidine and chlorpromazine were given as "rescue medication" to treat shivering. General anaesthesia was planned to be induced after cooling was complete. Rewarming was initiated at dural closure. Three patients successfully completed the protocol, cooling to 33.8 degrees C at a median rate of 3.6 (range: 3.4-3.8) degrees C/h. Two patients cooled to 33.8 degrees C but required treatment for shivering (cooling rate: 2.9 [2.8-3.1] degrees C/h). Four patients failed to cool adequately because of refractory shivering (cooling rate: 20 [1.5-2.9] degrees C/h). One patient did not shiver and yet failed to cool adequately (cooling rate: 0.76 degrees C/h). Rewarming was at a rate of 26 (1.2-4.3) degrees C/h. There were no significant complications arising from catheter placement. The combination of skin warming and pethidine was not reliable enough to be recommended for use during endovascular cooling in unanaesthetized patients.

GABA neurotransmission in the cerebellar interposed nuclei: involvement in classically conditioned eyeblinks and neuronal activity

The cerebellar interposed nuclei (IN) are an essential part of circuits that control classically conditioned eyeblinks in the rabbit. The function of the IN is under the control of GABAergic projections from Purkinje cells of the cerebellar cortex. The exact involvement of cerebellar cortical input into the IN during eyeblink expression is not clear. While it is known that the application of gamma-aminobutyric acid-A (GABA(A)) agonists and antagonists affects the performance of classically conditioned eyeblinks, the effects of these drugs on IN neurons in vivo are not known. The purpose of the present study was to measure the effects of muscimol and picrotoxin on the expression of conditioned eyeblinks and the activity of IN cells simultaneously. Injections of muscimol abolished conditioned responses and either silenced or diminished the activity of IN cells. Two injections were administered in each picrotoxin experiment. The first injection of picrotoxin slightly modified the timing and amplitude of the eyeblink, produced mild tonic eyelid closure, increased tonic activity of IN cells, and reduced the amplitude of the neural responses. The second injection of picrotoxin abolished conditioned responses, further increased tonic eyelid closure, dramatically elevated the tonic activity of IN cells, and in most cases, abolished neuronal responses. These results demonstrate that both GABA(A)-mediated inactivation and tonic up-regulation of IN cells can interrupt the expression of conditioned eyeblinks and that this behavioral effect is accompanied by the suppression of the neuronal activity correlates of the conditioned stimulus and response.

Video recording system for the measurement of eyelid movements during classical conditioning of the eyeblink response in the rabbit

Classical conditioning of the eyeblink response in the rabbit is a popular model for studying the neural substrates of associative learning. Most of the common eyeblink recording techniques require invasive procedures. To perform experiments in intact animals, a non-invasive, high-speed video recording system was developed to measure eyeblink responses of rabbits during classical conditioning experiments. Besides being non-invasive, this method does not require excessive restraint of the animal. The PC-based system combines a Pulnix video camera with National Instruments video capture and timing hardware to control the experiment and acquire images of the peri-ocular region. The software developed for controlling these experiments also detects the eyeblink by measuring the movement of the upper and lower eyelids, the area of the exposed surface of the eye, and head movements in the sagittal plane. The time resolution of this relatively inexpensive system is 8.33 ms, and at a working distance of 0.8 m, it can detect movements as small as 0.11 mm.

Doctors overlook sexual histories too often

Despite 20 years of HIV/AIDS, despite blatantly sexual content in prime time television programming, despite adult-content shows like HBO's "Sex and the City," and despite the easy availability of pornographic pictures and literature on the Internet, American clinicians and their patients still remain squeamish when it comes to discussing sexual activity. At least that's one conclusion that can be drawn from research that suggests physicians often fail to screen their patients for STDs or to assess their risk for HIV infection through sexual activity.

Management of urethritis in health maintenance organization members receiving care at a multispecialty group practice in Massachusetts

BACKGROUND

Cost containment has led to a concern that health maintenance organization-insured patients presenting with complaints of urethritis may be treated without being tested.

GOAL

To determine the proportion of men presenting with symptoms of urethritis who are tested for Chlamydia trachomatis and Neisseria gonorrhoeae.

STUDY DESIGN

Reviews were performed on 196 randomly selected patient records with an outpatient visit and a diagnostic code consistent with urethritis between 1995 and 1997. Data were collected on demographics, diagnostic testing, and treatment.

RESULTS

Diagnostic testing for C trachomatis and N gonorrhoeae was performed, respectively, in 92.3% and 83.2% of the men presenting at an initial visit with complaints of urethritis. Altogether, 98.2% of the patients who met the Centers for Disease Control criteria for documenting urethritis were tested for C trachomatis and N gonorrhoeae.

CONCLUSION

Diagnostic testing for C trachomatis and N gonorrhoeae is nearly universal in this multispecialty group practice setting, facilitating surveillance and public health efforts.

Multiple subpial transection in Landau-Kleffner syndrome

We have considered multiple subpial transection (MST) as a treatment option for Landau-Kleffner syndrome (LKS) for the past 6 years. The effect of this technique on language and cognitive ability, behaviour, seizures, and EEG abnormalities is analysed here. Five children (4 males, 1 female; aged 5.5 to 10 years) underwent MST with sufficiently detailed pre- and postoperative data for analysis. Behaviour and seizure frequency improved dramatically after surgery in all children. Improvement in language also occurred in all children, although none improved to an age-appropriate level. All five had electrical status epilepticus in sleep (ESES) before surgery, which was eliminated by the procedure. One child has had an extension of his MST due to the recurrence of ESES and accompanying clinical deterioration with good effect. An attempt is made to set the effect of MST against the natural history of the condition. MST is an important treatment modality in LKS, although the timing of this intervention and its effect on final language outcome remains to be defined.

Intermediate cerebellum and conditioned eyeblinks. Parallel involvement in eyeblinks and tonic eyelid closure

The intermediate cerebellum (the intermediate cerebellar cortex and interposed nuclei) and associated brainstem circuits are essential for the acquisition and expression of classically conditioned eyeblinks in the rabbit. The purpose of the present experiment was to determine whether these circuits are also involved in adaptive eyelid closure learned in an instrumental paradigm. For that purpose, rabbits with unrestrained eyelids were trained in two tasks: (1) classical conditioning of the eyeblink; and (2) a new instrumental task in which they avoided delivery of an aversive stimulus by maintaining tonic eyelid closure. To examine the involvement of the intermediate cerebellum in these two types of learned behavior, the cerebellar interposed nuclei were injected with the GABAA agonist muscimol and with the GABAA antagonist picrotoxin. Inactivating the interposed nuclei with muscimol abolished classically conditioned eyeblinks and severely affected the rabbit's capacity to maintain tonic eyelid closure. On the other hand, reducing inhibition with picrotoxin failed to interrupt the learned responses and increased the amplitude of eyelid closure. These data indicate that the cerebellar interposed nuclei control both phasic classically conditioned eyeblinks and tonic instrumental eyelid closure. To account for this new finding, a "hybrid" hypothesis combining the cerebellar learning hypothesis and the performance hypothesis is proposed.

Psychogenic non-epileptic seizures: management and prognosis

AIM

To determine the outcome and identify predictive factors in children with psychogenic non-epileptic seizures (PNES).

METHOD

The biographies of 35 children with PNES, attending a tertiary paediatric neurology centre, were reviewed.

RESULTS

Thirty five children attending the department between 1987 and 1997 were evaluated at a mean follow up of 4.6 years. The age range was 6-18 years. Twenty four were girls and 11 were boys. Eleven patients had a diagnosis of epilepsy with PNES, the remainder having PNES alone. Cause fell into four categories: a history of violence, abuse, or neglect; a high level of anxiety; dysfunctional family relationships; and attention seeking or avoidance behaviour. Management in all but five cases involved assessment and follow up by a child psychologist or child psychiatrist. The outcome was encouraging, with 66% of patients becoming PNES free. A further 23% have > 50% reduction in the frequency of PNES. Only two have had no reduction. Outcome was best in the group without epilepsy.

CONCLUSION

These results suggest that the prognosis of PNES is better in children than in adults, perhaps because causes are more likely to be external to the child, more easily identified, and more amenable to prompt intervention. The importance of good assessment, good communication, and a treatment plan that includes both symptom management and addressing the precipitating and perpetuating factors is emphasised.

Focal segmental glomerulosclerosis in children with acute lymphocytic leukemia: case reports and review of literature

PURPOSE

To report the occurrence of focal segmental glomerulosclerosis (FSGS) in children with acute lymphocytic leukemia (ALL), discuss pathogenesis and problems in management.

PATIENTS AND METHODS

Progressive renal dysfunction developed in two adolescent black girls with high-risk ALL who underwent renal biopsies that were consistent with FSGS. In both patients, no known etiologic factors, such as systemic lupus erythematosus, poststreptococcal glomerulonephritis, sickle cell anemia, or acquired immunodeficiency syndrome, were evident. FSGS induced by Adriamycin (Pharmacia & Upjohn, Columbus, OH) has been observed experimentally in rats. The patients had received anthracyclines and methotrexate, a known nephrotoxic chemotherapeutic agent.

RESULTS

One patient progressed to chronic renal failure and required prolonged dialysis followed by renal transplantation, though the leukemia remained in remission. The other patient is also in remission and on maintenance treatment for leukemia. She has persistent proteinuria and is currently undergoing a trial of high-dose steroid therapy.

CONCLUSION

The combination of FSGS with leukemia poses a management challenge to the clinician in terms of further treatment with potentially nephrotoxic drugs, complications of nephrotic syndrome (including infections), and timing of renal transplantation. Future studies should address whether FSGS represents a glomerular response to anthracycline-induced injury in susceptible black persons.

Performance characteristics of a rapid HIV antibody assay in a hospital with a high prevalence of HIV infection. CDC-Bronx-Lebanon HIV Serosurvey Team

BACKGROUND

The delay between collection of blood samples and availability of test results may be as long as 3 weeks and is one barrier to the acceptance of voluntary testing for human immunodeficiency virus (HIV) infection. Serologic tests that provide results rapidly could overcome this barrier, but the accuracy and reliability of rapid tests have not been well characterized in the United States.

OBJECTIVE

To evaluate, in a "real world" setting, the performance characteristics of a rapid HIV assay that reduces the need for patients to return for counseling after the test.

DESIGN

Testing of HIV antibodies by rapid and nonrapid assays and survey about risk behaviors for HIV.

SETTING

A hospital in Bronx, New York, with a high prevalence of HIV-seropositive patients.

PATIENTS

837 patients who were not known to be infected with HIV, had not been admitted for conditions related to the acquired immunodeficiency syndrome, and agreed to participate in HIV testing and an interview.

MEASUREMENTS

Sensitivity and specificity of a rapid HIV antibody assay based on comparisons with nonrapid assay and Western blot assay.

RESULTS

According to nonrapid assays, 5.4% of patients were infected with HIV. The rapid assay was highly accurate in this sample overall: its sensitivity was 1.00, its specificity was 0.991, its positive predictive value was 0.865, and its negative predictive value was 1.00. The assay was also highly accurate in various subgroups.

CONCLUSIONS

Accurate, rapid tests for HIV infection may enhance testing programs by preventing the need for delayed counseling of seronegative patients and by providing preliminary results to seropositive patients. These preliminary results may encourage patients to return for confirmatory test results and to adopt risk-reducing behaviors sooner.

Salvaging self: a grounded theory of pregnancy on crack cocaine

A grounded theory was developed to describe how pregnant crack cocaine users perceived their problems and responded to them. A basic social psychological process, salvaging self, was identified from constant comparative analysis of in-depth interviews with 60 pregnant or postpartum women who used crack cocaine an average of at least once per week in pregnancy. Salvaging self included two phases, facing the situation and evading harm. Participants evaluated the value, hope, and risk of various responses to pregnancy. Actions included strategies of harm reduction and stigma management aimed at reducing damage to the fetus, their identities as individuals and mothers, and the maternal-child relationship. Personal histories and social contexts influenced the salvaging process.

The combination of lovastatin and enalapril in a model of progressive renal disease

Puromycin-induced nephrotic syndrome is an animal model of progressive renal disease. Both angiotensin converting enzyme inhibitors and lipid-lowering agents have been used to preserve renal structure and function in this model, although neither completely prevents progression. We tested the hypothesis that the combination of the two agents would be more protective than either alone. Rats were divided into five groups; all were uninephrectomized. Four groups were given puromycin at a dose of 10 mg/100 g body weight (BW) with additional doses of 4 mg/100 g BW given intraperitoneally at 4, 5, and 6 weeks thereafter. One group was given enalapril (EN) 50 mg/l dissolved in the drinking water; the second received lovastatin (L) 15 mg/kg given daily by gavage; the third received both agents; the fourth was left untreated, and the final group received no puromycin and served as the control group. Eight weeks after the initial dose of puromycin, glomerular filtration rate (GFR), as inulin clearance, and protein excretion were determined and blood was collected for cholesterol and triglycerides. Blood pressure was not different between any of the groups. At the end of the study period, serum cholesterol [mean +/- SD, 252 +/- 185 mg/dl (L), 135 +/- 101 mg/dl (L + EN)] and triglycerides (239 +/- 200, 148 +/- 158 mg/dl) were significantly lower (P < 0.001) in the lovastatin-treated groups than in the untreated puromycin group (535 +/- 255 mg/dl and 579 +/- 561 mg/dl, cholesterol and triglyceride, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Knowledge, attitudes and beliefs about HIV infection and AIDS among healthy factory workers and their wives, Kinshasa, Zaire

As a first step in designing an AIDS prevention program at a large factory in Kinshasa, Zaire, we collected information on attitudes towards human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) from factory foremen and their wives. Trained moderators conducted twelve focus group discussions (from November through December 1987) that addressed knowledge, attitudes and beliefs about HIV infection and AIDS. In general, participants were familiar with HIV infection and AIDS and considered these conditions leading health problems in Kinshasa. Although participants had a fairly accurate understanding of the causes of HIV infection, modes of transmission and preventive measures, many myths and misconceptions existed. Many participants did not believe that condom use would consistently prevent infection through sexual intercourse. Participants strongly favored the counseling of seropositive persons but showed less consensus about whether the spouse of a seropositive person should be notified of the partner's test result. Participants predicted that couples in which one member is seropositive and the other is not would experience marital discord and friction with family, neighbors and co-workers. These findings were applied to the development of a counseling and educational program for seropositive factory employees and their spouses.

Results of routine restaurant inspections can predict outbreaks of foodborne illness: the Seattle-King County experience

To analyze the association between the results of routine inspections and foodborne outbreaks in restaurants, we conducted a matched case-control study using available data from Seattle-King County, Washington. Case restaurants were facilities with a reported foodborne outbreak between January 1, 1986 and March 31, 1987 (N = 28). Two control restaurants with no reported outbreaks during this period were matched to each case restaurant on county health district and date of routine inspection (N = 56). Data from the routine inspection that preceded the outbreak (for case restaurants) or the date-matched routine inspection (for control restaurants) were abstracted from computerized inspection records. Case restaurants had a significantly lower mean inspection score (83.8 on a 0 to 100 point scale) than control restaurants (90.9). Restaurants with poor inspection scores and violations of proper temperature controls of potentially hazardous foods were, respectively, five and ten times more likely to have outbreaks than restaurants with better results. Although this study demonstrates that Seattle-King County's routine inspection form can successfully identify restaurants at increased risk of foodborne outbreaks, it also illustrates that more emphasis on regulation and education is needed to prevent outbreaks in restaurants with poor inspection results.

Dispersed rat parotid acinar cells. I. Morphological and functional characterization

Morphologically and functionally intact acinar cells have been obtained from the rat parotid gland through enzymatic dispersion with pure collagenase, hyaluronidase, and trypsin as well as mild mechanical forces. Cell yields of 30-50% of the original tissue weight with over 95% acinar cells were accomplished. The cells in suspension assumed a more or less spherical shape but the intracellular polarity of organelle distribution was maintained. The cells in suspension at 37 degrees C maintained stable monovalent cationic composition but lost potassium and gained sodium rapidly upon exposure to ouabain, 10(-5) M. The intracellular amylase concentration and the patterns of secretion of amylase and of synthesis of cyclic AMP by the cells in response to adrenergic stimulation with epinephrine or isoproterenol were comparable to those of the intact gland in situ. In addition, the cells showed good O2 consumption and maintained it constant for periods up to 8 h. These cells could be used as experimental tools for in vitro studies of receptor physiology and biochemistry, cell membrane function, cellular secretory mechanisms, and other parameters of exocrine gland cell physiology.