Cutaneous crystal storing histiocytosis: A case series with review of literature

Crystal-storing histiocytosis (CSH) is a rare condition in which crystals accumulate in the cytoplasm of histiocytes and is usually associated with a lymphoplasmacytic neoplasm. Cutaneous CSH is extraordinarily rare and limited to case reports in the literature. We report two cases of this disease with cutaneous involvement. Case 1 was a 65-year-old male with a 4-month history of a pruritic eruption that started as a solitary pink to skin-colored indurated plaque on the anterior neck before progressing to involve the whole neck, chest wall, and face. Case 2 was a 54-year-old woman with a history of unspecified "lymphoma" who presented with a soft nodule on the forearm. Biopsies from both cases had similar findings and showed a proliferation of epithelioid cells with pink cytoplasm and intracellular crystalline structures infiltrating the dermis and subcutaneous fat. In the first case, the cells were positive for CD43, CD45, CD68, and IgG kappa, and in the second case, the crystals were positive for IgG lambda. Based on these findings, the patients were diagnosed with cutaneous CSH. We highlight this rare diagnosis and the importance of investigating an underlying lymphoplasmacytic neoplasm.

Marginal corneal infiltrates as an ocular manifestation of acute generalized exanthematous pustulosis

Purpose

To report a case of keratoconjunctivitis with marginal corneal infiltrates in a patient with acute generalized exanthematous pustulosis (AGEP) secondary to trimethoprim-sulfamethoxazole.

Observations

A 63-year-old female presented with a diffuse pustular skin rash and bilateral keratoconjunctivitis with marginal corneal infiltrates. Skin biopsy led to the diagnosis of AGEP secondary to trimethoprim-sulfamethoxazole use. Treatment of the ocular findings with topical corticosteroids and lubrication led to near-full resolution after two weeks.

Conclusions and Importance

To the best of our knowledge, this is the first reported association between AGEP and keratoconjunctivitis with marginal corneal infiltrates. A hypersensitivity reaction to a foreign antigen is implicated in the pathogenesis of both AGEP and sterile marginal infiltrates, and we suggest that the patient's underlying hypersensitivity process associated with AGEP accounted for the ocular findings.

Maternal collapse in pregnancy

Maternal collapse is a rare life-threatening event that can occur at any stage of pregnancy or up to 6 weeks postpartum. Prompt identification and timely intervention by a multidisciplinary team that includes an obstetrician, midwifery staff and an obstetric anaesthetist are essential to improve maternal and fetal outcomes. Standard adult resuscitation guidelines need to be followed with some modifications, taking into account the maternal-fetal physiology, which clinicians should be familiar with. During cardiac arrest, the emphasis is on advanced airway management, manual uterine displacement to relieve aortocaval compression and performing a resuscitative hysterotomy (peri-mortem caesarean delivery) swiftly in patients who are more than 20 weeks gestation to improve maternal survival. Annual multidisciplinary simulation training is recommended for all professionals involved in maternity care; this can improve teamwork, communication and emergency preparedness during maternal collapse.

Dual treatment of cutaneous leishmaniasis with topical amphotericin B and photodynamic therapy in a pediatric patient

Cutaneous leishmaniasis is a parasitic infection that can result in scarring, contributing to significant morbidity when a cosmetically sensitive area is involved. We report a case of a 13-year-old boy with cutaneous leishmaniasis involving the face and arm. He was treated with a combination of photodynamic therapy as well as topical amphotericin with a cosmetically satisfying outcome. This combination of noninvasive treatment regimens has not been reported to our knowledge and merits further study in the pediatric population.

Peripartum management of tuberous sclerosis complex complicated by massive angiomyolipomas

Tuberous sclerosis complex is a genetic disease that can affect multiple organs, commonly the renal, central nervous, cardiac and respiratory systems. Here, we present the peripartum management of a woman with a new diagnosis of tuberous sclerosis complex associated with massive renal angiomyolipomas. There was significant risk of catastrophic haemorrhage from the angiomyolipomas during pregnancy. This created a challenging scenario for the anaesthetists, obstetricians, urologists and interventional radiologists involved in their care, necessitating collaborative working, numerous investigations and honest patient-centred discussions. Evidence for the management of tuberous sclerosis and angiomyolipomas in pregnancy does not appear to have been previously reported. After much consideration, arterial embolisation of the most vascular area of the angiomyolipoma was completed at 28 weeks gestation under remifentanil sedation. An elective caesarean section under combined spinal epidural anaesthesia was completed at 37 + 3 weeks gestation. Central nervous system involvement must always be considered; benign tumours within the brain and spinal cord may contraindicate neuraxial techniques. Early multidisciplinary involvement is essential due to the diverse and complex nature of tuberous sclerosis. Individuals differ in their presentation and disease severity; therefore, they must be assessed on an individual basis with management tailored accordingly.

Novel Diagnostic Educational Resource: Use of a web-based adaptive learning module to teach inflammatory reaction patterns in dermatopathology to medical students, residents, and fellows

Background

Perceptual and adaptive learning modules (PALM’s) provide a large number of visual examples for evaluation and accommodate to learner performance by actively adjusting the module parameters.

Methods

We developed a module for discriminating 5 inflammatory reaction patterns using the Novel Diagnostic Educational Resource (NDER) platform. The module included a 20 question pre-test, a 200 question training section, and a 20 question post-test. During the pre-test and post-test, images were displayed for an indefinite period of time with no feedback given. In the training section, images were displayed for a duration inverse to learner performance, and after submitting their response learners were immediately shown the correct answer. The performance of module participants was compared to a control group who completed pre-test and post-test only.

Results

26 pathology and dermatology residents completed the module and were included in analysis. Pre-test and post-test scores showed an average increase of 17.1 percentage points (95% CI 13.0 to 21.2, P < 0.001). When performance on pre-test and post-test was compared between the module and control groups, module group performance increased more than control group performance by an average of 10.1 percentage points (95% CI -2.5 to 17.8, P = 0.0119). 84% (37) of participants found the module somewhat useful or very useful and 68% (30) of participants would be pretty likely or very likely to recommend to another trainee.

Conclusions

Our findings validate the use of NDER for teaching inflammatory reaction patterns. Participants generally had favorable feedback regarding the interface and teaching potential of the module. Including a late re-test as part of the module would be beneficial in further validating future iterations. Next steps include optimizing module performance and developing module content for more advanced learners.

Realizing topologically ordered states on a quantum processor

[Figure: see text].

Decision-to-delivery interval and neonatal outcomes for category-1 caesarean sections during the COVID-19 pandemic

General anaesthesia is known to achieve the shortest decision‐to‐delivery interval for category‐1 caesarean section. We investigated whether the COVID‐19 pandemic affected the decision‐to delivery interval and influenced neonatal outcomes in patients who underwent category‐1 caesarean section. Records of 562 patients who underwent emergency caesarean section between 1 April 2019 and 1 July 2019 in seven UK hospitals (pre‐COVID‐19 group) were compared with 577 emergency caesarean sections performed during the same period during the COVID‐19 pandemic (1 April 2020–1 July 2020) (post‐COVID‐19 group). Primary outcome measures were: decision‐to‐delivery interval; number of caesarean sections achieving decision‐to‐delivery interval < 30 min; and a composite of adverse neonatal outcomes (Apgar 5‐min score < 7, umbilical arterial pH < 7.10, neonatal intensive care unit admission and stillbirth). The use of general anaesthesia decreased significantly between the pre‐ and post‐COVID‐19 groups (risk ratio 0.48 (95%CI 0.37–0.62); p < 0.0001). Compared with the pre‐COVID‐19 group, the post‐COVID‐19 group had an increase in median (IQR [range]) decision‐to‐delivery interval (26 (18–32 [4–124]) min vs. 27 (20–33 [3–102]) min; p = 0.043) and a decrease in the number of caesarean sections meeting the decision‐to‐delivery interval target of < 30 min (374/562 (66.5%) vs. 349/577 (60.5%); p = 0.02). The incidence of adverse neonatal outcomes was similar in the pre‐ and post‐COVID‐19 groups (140/568 (24.6%) vs. 140/583 (24.0%), respectively; p = 0.85). The small increase in decision‐to‐delivery interval observed during the COVID‐19 pandemic did not adversely affect neonatal outcomes.

Determination of D-Malic Acid in Apple Juice by Liquid Chromatography: Collaborative Study

Eleven laboratories collaboratively studied a liquid chromatographic (LC) method for determination of D-malic acid in apple juice. The mobile phase consisted of 16 mM L-valine and 8 mM copper acetate adjusted to pH 5.5 with NaOH. The UV detector was set at 330 nm, and a single reversed-phase LC column was used. Seven paired samples containing various amounts of D-malic acid ranging from 0 to 188 mg/100 mL of 12 Brix pasteurized apple juice were tested by each collaborator. Repeatability and reproducibility coefficients of variation ranged from 1.0 to 3.5% and 7.7 to 11.7%, respectively, within the range of 26 to 188 mg D-malic acid/100 mL of 12 Brix apple juice. The collabora tive study results demonstrated that the method could quantitate the economic adulteration of ap ple juice with DL-malic acid at lower levels than those reported with previous methods. The LC method for determination of D-malic acid in apple juice has been adopted first action by AOAC INTERNATIONAL.

An evaluation of two decision-making scales for children with life-limiting illnesses

PURPOSE

Annually, about 500,000 children are coping with life-limiting illnesses. Many of these children could benefit from pediatric palliative care which provides supportive services. These services can also aid parents in decision making. In order to measure the effect of pediatric palliative care programs on decision making, a valid and reliable tool must be identified. This study aims to validate the psychometric properties of the Decisional Conflict Scale (DCS) and the COMRADE instruments for children with life-limiting illnesses.

METHODS

Analyses were conducted using survey data collected from 266 parents whose Medicaid enrolled children have life-limiting illnesses.

RESULTS

Results of the analyses suggest that the DCS has better psychometric properties for measuring decision making within the population of children with life-limiting illnesses than the COMRADE.

CONCLUSION

Pediatric palliative care programs should use the DCS to measure the effectiveness of services aimed at supporting families with high levels of decisional conflict.

Paediatricians' perceptions on referrals to paediatric palliative care

Children have traditionally been referred to palliative care when curative treatments were exhausted. Recently, experts have suggested that children could benefit from palliative care early in their courses of illness. Using survey data from 303 paediatricians in Florida and California, this study assesses if paediatricians would refer children to palliative care early in their course of illness. Results showed that more years in practice were associated with decreased odds of referring children to palliative care. Academic practice setting and more Medicaid patients were associated with greater odds of referral prior to the end of life. Hispanic paediatricians, those with more experience and those who practice in a hospital setting were associated with decreased odds of referral prior to the end of life. Results suggest that health planners who wish to implement or refine integrated paediatric palliative care programs should consider outreach strategies targeted at paediatricians with specific characteristics.

Numerical analysis of an anastomotic device

The explicit dynamic finite element method was utilized to investigate the deformation behaviour of a woven wire mesh tubular device that is used in a side-to-side anastomotic procedure for achieving gastrointestinal anastomosis. The numerical model was initially verified by comparison to experimental results that were obtained using a specialized testing mechanism. Once validated, the finite element model (FEM) was parameterized to ascertain the influence of several device parameters on its deformation behaviour. The importance of these parameters, as related to its optimal design for use in minimally invasive surgery (MIS), was subsequently ascertained and discussed.

Heart rate variability during sympatho-excitatory challenges: comparison between spontaneous and metronomic breathing

Respiration influences heart rate variability, leading to the suggestion that respiration should be controlled to assess autonomic function by using heart rate variability. Clearly, control of respiration is advantageous or even essential in several experimental circumstances. However, control of respiration, by itself, produces a small, but significant, increase in mean heart rate and a decrease in respiratory synchronous variation in heart rate. We tested whether, in some experimental situations, it may be possible to arrive at similar interpretation about autonomic function with and without using control of respiratory rate. Heart rate spectral powers from nine subjects were compared between spontaneous and metronomic breathing during two sympatho-excitatory stresses, lower body negative pressure (LBNP) and head up tilt (HUT). The normalized spectral powers in supine and HUT during spontaneous breathing were: 0.43 and 0.75 in very low (VLF) and 0.28 and 0.09 in high frequency (HF) regions. The powers during metronomic breathing were: 0.36 and 0.82 (VLF) and 0.36 and 0.09 (HF). The powers in supine and LBNP during spontaneous breathing were: 0.43 and 0.81 (VLF) and 0.28 and 0.06 (HF). The powers during metronomic breathing were: 0.36 and 0.80 (VLF) and 0.36 and 0.07 (HF). All p values were <0.05. Therefore, changes in heart rate spectral powers during HUT and LBNP were similar during metronomic breathing and spontaneous breathing. These results suggest that in experimental designs such as in our study, using metronomic breathing may not provide any additional insight into autonomic function than that can be obtained during spontaneous breathing.

Quality control limits for broth microdilution susceptibility tests of ten antifungal agents

Broth microdilution susceptibility tests of Candida species have now been standardized by the National Committee for Clinical Laboratory Standards (NCCLS). An eight-laboratory collaborative study was carried out in order to document reproducibility of tests of Candida parapsilosis ATCC 22019 and Candida krusei ATCC 6258 by the NCCLS method. Replicate broth microdilution tests were used to define control limits for 24- and 48-h MICs of amphotericin B, flucytosine, fluconazole, voriconazole, ketoconazole, itraconazole, caspofungin (MK 0991), ravuconazole (BMS 207147), posaconazole (SCH 56592), and LY 303366.

Nonnasopharyngeal lymphoepithelioma of the head and neck

BACKGROUND

Lymphoepithelioma (squamous cell carcinoma with associated lymphoid stroma) commonly occurs in the nasopharynx, rarely at other sites. As a result, the clinical course and optimal treatment of nonnasopharyngeal lymphoepithelioma of the head and neck have not been well described. This retrospective study was undertaken to analyze the clinical course of the disease in patients treated at a single institution and to formulate recommendations for treatment based on that experience as well as results reported in the literature.

METHODS

Between 1950 and 1994, 34 patients with nonnasopharyngeal lymphoepithelioma of the head and neck were treated at the University of Texas M. D. Anderson Cancer Center. The patients' medical records were reviewed and their pathologic specimens evaluated. The primary tumor sites were: oropharynx (24 patients), salivary gland (4), laryngohypopharynx (4), and the maxillary sinus/nasal cavity (2). Assessed in accordance with the 1992 American Joint Committee Against Cancer TNM staging system, T classifications were TX-2, T1-7, T2-8, T3-10, and T4-7, and N classifications were N0-8, N1-5, N2-15, and N3-6. Treatment consisted of radiotherapy for 24 patients, excisional biopsy of the primary tumor followed by radiotherapy for 7 patients, and surgery for 3 patients. Of the patients treated with radiotherapy, neck dissections were performed on only two, both of whom had persistent lymph node masses after completing radiotherapy. The median dose delivered to the primary tumor was 65 gray (Gy) (range, 46-78 Gy). The median fraction size was 2.1 Gy (range, 1.6-3.2 Gy).

RESULTS

The 5-year actuarial disease specific survival and overall survival rates were 59% and 39%, respectively. The 5-year actuarial local control rate for all patients was 94%. For the irradiated patients, the 5-year regional control rates were 77% overall and 83% within the radiation field. The 5-year actuarial rate of distant metastasis for all patients was 30%. For patients who presented with and without regional adenopathy, the 5-year rates of distant metastasis were 36% and 12%, respectively (P = 0.27).

CONCLUSIONS

Nonnasopharygeal lymphoepithelioma is a radiosensitive disease. High rates of locoregional tumor control were achieved with radiotherapy at all head and neck sites. The main cause of treatment failure was distant metastasis, which occurred more frequently in patients with lymph node involvement. Radiotherapy is appropriate initial locoregional therapy for patients with this disease. Surgery should be reserved for patients who have persistent disease after completing radiotherapy. Systemic therapy is a reasonable approach for patients who present with regional adenopathy because they have a relatively high rate of distant metastasis.

Use of amplitude-modulated breathing for assessment of cardiorespiratory frequency response within subrespiratory frequencies

We present a new technique which uses amplitude-modulated breathing patterns to obtain estimates of frequency response between respiration and heart rate within subrespiratory frequencies. Frequency response between respiration and heart rate has been previously estimated using broadband respiration and metronomic breathing. However, the estimates obtained using these techniques show low coherence between respiration and heart rate within the subrespiratory frequencies (< 0.12-0.15 Hz). The advantages of amplitude-modulated breathing are: enhancement in the degree of perturbation within subrespiratory frequencies as indicated by relatively higher coherencies between respiration and heart rate (approximately equal to 0.7), and the subjects do not have to breathe at very low breathing frequencies or resort to breath holds. Use of a squared sine wave carrier modulated by sinusoidal functions enabled us to obtain energy distributions at subrespiratory frequencies without using demodulation. Results obtained at eight subrespiratory frequencies from ten subjects show that the new technique is easy to implement and produces relatively higher coherence between respiration and heart rate. The advantage of the new technique in terms of enhancing the level of perturbations within subrespiratory frequencies is particularly important, because it is in this frequency range that the interpretation of variability in heart rate in terms of autonomic origins is incompletely understood and is confounded by respiratory interactions.

Hemodynamic responses to the stroop and cold pressor tests after submaximal cycling exercise in normotensive males

The effect of 30 min of cycling exercise at 60% VO2max on hemodynamic responses to the Stroop and cold pressor tests in 12 normotensive males was examined. Subjects were randomly assigned in a counterbalanced design to perform the stressors pre- and postexercise and served as their own controls. Cardiac output (CO), heart rate (HR), and stroke volume were measured continuously by impedance cardiography. Blood pressure was measured beat to beat using a photoplethysmographic volume transducer. Total peripheral resistance (TPR) was calculated. The systolic blood pressure response (elevation) to the Stroop test was significantly attenuated postexercise (4.2 +/- 1.4%, p < 0.05) as compared to preexercise and control (10.1 +/- 1.8%). Postexercise HR reactivity was also significantly attenuated to the Stroop test postexercise (0.3 +/- 1.7%) compared to preexercise and control (6.5 +/- 2.3%, p < 0.05). Hemodynamic variables among treatment groups, with the possible exception of HR, appeared to be unaffected during the cold pressor postexercise. Neither central (i.e., CO) nor peripheral (i.e., TPR) responses appeared to be solely responsible for the attenuated blood pressure response to the Stroop stressor.

[Peripheral retinal cryocoagulation. Long-term outcome]

Peripheral retinal cryotherapy alone, without additional cyclocryotherapy, can for the short term lead to intraocular pressure reduction and regression of neovascularization. As there is little information concerning the long-term results of this treatment we reexamined all patients treated with peripheral retinal cryotherapy at the Department of Ophthalmology at Freiburg University between 1979 and 1990.

PATIENTS AND METHODS

Neovascularization was secondary to proliferative diabetic retinopathy in 33 eyes (65%), secondary to retinal vascular occlusion in 13 eyes (25%), and secondary to a combination of both in 5 eyes (10%). Usually, 2 quadrants of each eye were treated with 9 applications per quadrant.

RESULTS

Intraocular pressure was adequately reduced in 49% of the eyes and rubeosis iridis regressed in 57%. Visual acuity deteriorated in 53% of all cases.

CONCLUSION

Intraocular pressure and rubeosis iridis can in the long term successfully be treated with peripheral retinal cryotherapy. Despite good intraocular pressure control and regression of rubeosis iridis visual acuity does not improve.

Alterations in pharmacodynamics of anxiolytics in abstinent alcoholic men: subjective responses, abuse liability, and electroencephalographic effects of alprazolam, diazepam, and buspirone

Subjective responses, including those associated with abuse liability and changes in frontal electroencephalographic activity, were assessed in abstinent alcoholic men and control subjects after administration of alprazolam, diazepam, buspirone, and placebo. Plasma concentrations of alprazolam, diazepam, and desmethyldiazepam also were determined. Abuse liability scales were elevated for alcoholic participants above control levels after alprazolam and diazepam. Areas under the concentration-time curve differed only for desmethyldiazepam, which was lower for the alcoholic participants. Compared with control subjects, alcoholic participants had greater declines in the absolute power of the alpha band after diazepam challenge. Alcoholic participants, unlike control subjects, had areas under the effect-time curve for alpha and theta bands that were lower after administration of alprazolam or diazepam than they were after receiving placebo. These results suggest that alprazolam and diazepam are more likely to be abused by alcoholic men than by nonalcoholic men and that alcoholic men have enhanced sensitivity to the effects of benzodiazepines on alpha and theta activity.

Detection of extended-spectrum-beta-lactamase-producing members of the family Enterobacteriaceae with Vitek ESBL test

A three-phase analysis of the Vitek ESBL test and a double-disk (2 disk) test was performed to assess their ability to detect extended-spectrum beta-lactamases (ESBLs) in members of the family Enterobacteriaceae. In the first two phases involving detection of ESBLs in 157 stains processing well-characterized beta-lactamases, sensitivity and specificity were found to be 99.5 and 100%, respectively, for the Vitek ESBl test and 98.1 and 99.4%, respectively, for the 2-disk test. In the third phase, in which the ability of each test to detect ESBLs in 295 clinical isolates was assessed, there was only one false positive (Vitek ESBL test). Across all three phases, the Vitek ESBL test was found to be much easier to perform than the 2-disk test. The latter also involved subjective interpretation of results. There were a total of 176 Escherichia coli and 157 Klebsiella pneumoniae isolates and less than 40 isolates of each of 14 other species evaluated. In a supplemental study of Klebsiella oxytoca, an organism possessing a chromosomal beta-lactamase similar to an ESBL, the Vitek ESBL test was found to be capable of detecting hyperproduction of this enzyme in strains of this species as well. These data indicate that the Vitek ESBL test is reliable for the detection of ESBLs in E. coli and K. pneumoniae, the two species in which ESBLs are most common, and of hyperproduction of the K. oxytoca beta-lactamase, a situation which engenders a level of resistance to this species similar to that seen with ESBLs.

Photoinduced electron transfer from nucleotides to DNA intercalating viologens. A study by laser-flash photolysis and spectroelectrochemistry

Fluorescent DNA-binding N,N'-dialkyl 6-(2-pyridinium)phenanthridinium dications (where dialkyl stands for -(CH2)2-or-(CH2)3-, abbreviated dq2pyp and dq3pyp, respectively) associate with GMP (guanosine-5'-monophosphate) in 0.1-mol l-1, pH 3.5-5.5, phosphate buffer solution to yield 1:1 and 1:2 non-emissive complexes, the formation constants of which range from 197-63 and 19-11 l mol-1, respectively. In addition to the strong static quenching, dynamic deactivation of their excited state occurs at diffusion-controlled rate ki = 5.2 x 10(9) l mol-1 s-1). Illumination of the GMP-containing solutions of the dyes with a 355 nm laser pulse produces a transient, with strong absorbance at 510 and 720 nm for dq2pyp, and 420 and 560 nm for dq3pyp. An identical transient is produced in the presence of ascorbic acid instead of the mononucleotide. By comparison to the electrochemically generated absorption spectra of the monoreduced dyes, the photogenerated transients have been assigned unequivocally to their corresponding radical-cations, formed by electron transfer to the anglet excited state. The back redox reaction between the oxidized quencher and dq2pyp+ proceeds at a rate of 1-2 x 10(9) l mol-1 s-1. The same transient has been observed also for the DNA intercalated viologens; this result, together with the little ability of these dyes to sensitize the formation of singlet dioxygen or to produce superoxide anion, demonstrate that their DNA photocleavaging activity is initiated by an efficient light-induced electron transfer from the nucleobases.

Liability to alprazolam abuse in daughters of alcoholics

OBJECTIVE

The purpose of this study was to determine mood changes in women with a parental history of alcohol dependence (daughters of alcoholics) after challenge does of alprazolam and placebo in comparison with responses in women without a history of parental alcohol dependence.

METHOD

Visual analog scales that assess liability to benzodiazepine abuse were administered to 12 adult daughters of alcoholics and 11 comparison subjects after alprazolam challenge.

RESULTS

The daughters of alcoholics had greater pleasant mood responses after a single dose of alprazolam than did the comparison subjects despite having similar plasma alprazolam levels.

CONCLUSIONS

The findings of this study suggest that the mood-enhancing effects of alprazolam are greater in daughters of alcoholics than in subjects without a history of parental alcohol dependence.

An optimized index of human cardiovascular adaptation to simulated weightlessness

Prolonged exposure to weightlessness is known to produce a variety of cardiovascular changes, some of which may influence the astronaut's performance during a mission. In order to find a reliable indicator of cardiovascular adaptation to weightlessness, we analyzed data from nine male subjects after a 24-hour period of normal activity and after a period of simulated weightlessness produced by two hours in a launch position followed by 20 hours of 6 degrees head-down tilt plus pharmacologically induced diuresis (furosemide). Heart rate, arterial pressure, thoracic fluid index, and radial flow were analyzed. Autoregressive spectral estimation and decomposition were used to obtain the spectral components of each variable from the subjects in the supine position during pre- and post-simulated weightlessness. We found a significant decrease in heart rate power and an increase in thoracic fluid index power in the high frequency region (0.2-0.45 Hz) and significant increases in radial flow and arterial pressure powers in the low frequency region (<0.2 Hz) in response to simulated weightlessness. However, due to the variability among subjects, any single variable appeared limited as a dependable index of cardiovascular adaptation to weightlessness. The backward elimination algorithm was then used to select the best discriminatory features from these spectral components. Fisher's linear discriminant and Bayes' quadratic discriminant were used to combine the selected features to obtain an optimal index of adaptation to simulated weightlessness. Results showed that both techniques provided improved discriminant performance over any single variable and thus have the potential for use as an index to track adaptation and prescribe countermeasures to the effects of weightlessness.

Impact of chlorhexidine-silver sulfadiazine-impregnated central venous catheters on in vitro quantitation of catheter-associated bacteria

To assess the impact of the antiseptic effects of silver sulfadiazine-chlorhexidine-impregnated central venous catheters on catheter culture systems, a series of in vitro experiments was performed. Segments of antiseptic and non-antiseptic-impregnated catheters were sonicated in thioglycolate broth and removed. After the addition of 10(3) CFU of Staphylococcus epidermidis per ml, aliquots of catheter-exposed broth were subcultured onto blood agar at 15-min intervals. Decreased mean colony counts were noted at 45 min for broth exposed to antiseptic-impregnated catheters compared with the colony counts for broth exposed to non-antiseptic-impregnated catheters (170 versus 540 CFU/ml). These effects, which were also demonstrated by the roll-plate method, were abrogated by the use of medium containing inhibitors of silver sulfadiazine and chlorhexidine. To assess the duration of the antiseptic effects, catheter segments were suspended for up to 14 days in phosphate-buffered saline, incubated with 10(6) CFU of S. epidermidis per ml, and cultured. Inhibition of bacterial growth by antiseptic-impregnated catheters disappeared after 14 days. These studies suggest that antiseptic compounds elute from catheters during broth- and solid medium-based culturing processes, making necessary the addition of inhibitors of these compounds in culture media. They further suggest that the antimicrobial effects of antiseptic-impregnated catheters wane within several days of placement.

A multistage, optimal active contour model

Energy-minimizing active contour models or snakes can be used in many applications such as edge detection, motion tracking, image matching, computer vision, and three-dimensional (3-D) reconstruction. We present a novel snake that is superior both in accuracy and convergence speed over previous snake algorithms. High performance is achieved by using spline representation and dividing the energy-minimization process into multiple stages. The first stage is designed to optimize the convergence speed in order to allow the snake to quickly approach the minimum-energy state. The second stage is devoted to snake refinement and to local minimization of energy, thereby driving the snake to a quasiminimum-energy state. The third stage uses the Bellman (1957) optimality principle to fine-tune the snake to the global minimum-energy state. This three-stage scheme is optimized for both accuracy and speed.

Spectral patterns and frequency response characteristics of arterial pressure in heart paced dogs

The role of heart rate in buffering and/or generating aortic pressure (AP) oscillations that occur at rest and in response to oscillatory blood volume shifts was studied. Six supine dogs with chronic AV blockade were used to examine: 1) resting HR and AP spectra when the ventricular rate was controlled by atrial depolarization (natural sinus rhythm); 2) resting AP and stroke volume (SV) spectra when the heart was AV sequentially paced at 60, 120, and 180 bpm before and after ganglionic blockade; and 3) the frequency response characteristics of AP and SV to whole-body sinusoidal acceleration (+/- 2gz, 0.008-0.23 Hz) at each heart rate before and after ganglionic blockade. During atrial regulation of HR, the spectra of both AP and HR had dominant peaks located at the breathing frequency (0.2-0.4 Hz) and relatively smaller peaks centered at approximately 0.05 Hz. During constant heart rate pacing, the spectra of AP had a dominant component at approximately 0.05 Hz. The power of this component was: 1) larger than during atrial regulation, 2) increased with increasing pacing rate, and 3) abolished by ganglionic blockade. There was no effect of pacing rate or ganglionic blockade on SV spectra. During oscillatory acceleration, AP regulation in the heart paced dogs was frequency dependent. Regions of good regulation occurred below 0.016 Hz and above 0.1 Hz, and poor regulation between 0.035 and 0.075 Hz centered at approximately 0.05 Hz. The oscillations in the poor regulation region were enhanced by increased pacing rate. After ganglionic blockade, the frequency response of AP was primarily hydraulic (low-pass). The frequency response of SV had a neural component. We conclude that: 1) resting AP fluctuations at respiratory frequencies resulted from respiration-linked HR variation; 2) the 0.05-Hz fluctuations in AP during rest and the poor regulation of AP at 0.05 Hz during acceleration resulted from a peripheral vascular response that lagged disturbances by approximately 10 s; 3) HR regulation was important in minimizing AP variation in the 0.05-Hz region both at rest and during oscillatory acceleration; and 4) inotropic control of SV was an important component of AP regulation during low-frequency acceleration.

Multicenter clinical laboratory evaluation of a beta-lactamase disk assay employing a novel chromogenic cephalosporin, S1

S1, a new chromogenic cephalosporin (International BioClinical, Inc., Portland, Oreg.), was used to detect beta-lactamase production among a variety of commonly encountered bacteria in a four-center collaborative study. Results of an S1 disk assay were compared with those obtained by a nitrocefin-based disk procedure (Cefinase; Becton-Dickinson Microbiology Systems, Cockeysville, Md.), with repetitive testing of five quality control organisms and with individual tests of recent clinical isolates of Neisseria gonorrhoeae (162 strains), Haemophilus influenzae (162 strains), Moraxella catarrhalis (155 strains), Staphylococcus aureus (161 strains), and Bacteroides fragilis (164 strains). The performances of the two beta-lactamase disk assays were comparable for the first three species cited above. However, the S1 assay appeared to be a more sensitive procedure than the Cefinase assay when applied to S. aureus and B. fragilis, with respect to both total numbers of positive results and length of time to a definitive positive endpoint.

An animal model and computer-controlled surface pressure delivery system for the production of pressure ulcers

Pressure ulcers continue to be a major health care problem. This paper describes an animal model and surface pressure delivery system for the production of experimentally derived pressure ulcers. A method for inducing dermal pressure lesions on the fuzzy rat was developed using a computer-controlled displacement column which produced a constant tissue interface pressure. The pressure column consists of a force transducer located between two 0.5-in (1.27-cm) diameter metal cylinders. The desired cutaneous pressure is maintained by a computer-controlled miniature stepper motor which displaces the column with the aid of interactive software. The force transducer signal is converted from analog to digital form, amplified, and recorded. Blood perfusion is monitored using a laser Doppler flowmeter (located in the tip of the column) during the application of pressure. The application of 145 mmHg pressure for 5 consecutive 6-hr sessions resulted in a greater than 90% incidence of pressure ulcers. The implications of our model and contributions of earlier animal models are discussed. This model provides a tightly controlled and measured environment making possible the scientific study of ulcer development and the evaluation of potential preventative or curative compounds.

Revision of standards for adjusting the cation content of Mueller-Hinton broth for testing susceptibility of Pseudomonas aeruginosa to aminoglycosides

A multilaboratory study was undertaken to reassess the amount of calcium and magnesium that should be added to Mueller-Hinton broth when testing Pseudomonas aeruginosa against amikacin, gentamicin, isepamicin, netilmicin, and tobramycin. To achieve parity with agar dilution tests, cation-adjusted broth should contain 20 to 25 mg of calcium and 10 to 12.5 mg of magnesium per liter rather than the 50- and 25-mg/liter supplements recommended previously. For quality control of tests with contemporary media, MIC control limits should be adjusted by lowering the current MIC limits by at least 1 doubling-dilution interval.

Neuroanatomical localization of kappa 1 and kappa 2 opioid receptors in rat and guinea pig brain

The neuroanatomical localization of kappa opioid receptors in rat and guinea pig brain was determined by quantitative in vitro receptor autoradiography. Our study shows striking differences in kappa 1 and kappa 2 receptor distributions both between species and within each species. In the rat brain, kappa 1 sites (labeled by [3H]U-69,593) are of low density and confined to a small number of structures. These include the claustrum, endopiriform nucleus, caudate putamen, nucleus accumbens, midline nuclear group of the thalamus, superficial grey layer of the superior colliculus, and central grey. kappa 2 sites (labeled by [3H]ethylketocyclazocine or [3H]bremazocine under conditions in which mu, delta, and kappa 1 binding was suppressed) are more widely distributed throughout all levels of rat brain. kappa 2 sites occur at high density in the caudate putamen, nucleus accumbens, amygdala, thalamus, and interpeduncular nuclei. In guinea pig brain, kappa 1 sites predominate and are of high density in layers I and VI of the neocortex, claustrum, endopiriform nucleus, caudate putamen, nucleus accumbens, and molecular layer of the cerebellum. As in rat brain, kappa 2 sites in guinea pig are more uniformly and widely distributed throughout the brain than are kappa 1 sites. The highest density of kappa 2 sites is in the dorsal parabrachial nucleus, interpeduncular nuclei, mammillary nuclei, and posterior thalamic nuclei. Results from this study demonstrate important interspecies differences in the distribution of kappa 1 and kappa 2 opioid receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Reduction of left ventricular preload by lower body negative pressure alters Doppler transmitral filling patterns

The objective of this study was to evaluate the effect of alterations in preload induced by lower body negative pressure on Doppler transmitral filling patterns. Echocardiograms and Doppler recordings were performed in 18 normal young men (aged 23 to 32 years) during various levels of lower body negative pressure (0, -20 and -50 mm Hg). Lower body negative pressure induced a reduction in diastolic velocity integral (from 12.17 +/- 0.79 to 8.42 +/- 0.71 cm, p = 0.0067) and consequently left ventricular diastolic diameter (from 5.11 +/- 0.09 to 4.45 +/- 0.1 cm, p less than 0.0001). There was a significant reflex increase in heart rate from 59.9 +/- 1.9 to 77.1 +/- 2.4 beats/min (p less than 0.0001), but blood pressure was unchanged. This reduction in preload altered Doppler transmittral filling patterns as follows: 1) peak early velocity (E) decreased from 59.2 +/- 3.8 to 39.1 +/- 1.7 cm/s (p less than 0.0001); 2) atrial filing velocity (A) was unchanged (35.58 +/- 1.5 to 33.52 +/- 1.4 cm/s, p = 0.517); 3) E/A ratio decreased from 1.7 +/- 0.13 to 1.19 +/- 0.08 (p = 0.0087); 4) mean acceleration (from 482 +/- 37 to 390 +/- 27 cm/s2, p = 0.03) and mean deceleration (from 327 +/- 31 to 169 +/- 21 cm/s2, p less than 0.001) of the early filling wave were significantly reduced; and 5) peak acceleration (from 907 +/- 42 to 829 +/- 29 cm/s2) and peak deceleration (from 771 +/- 94 to 547 +/- 76 cm/s2) also decreased, but not significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of alterations in loading produced by lower body negative pressure on aortic blood flow acceleration

The objectives of this study were to evaluate the effects of alterations in loading induced by lower body negative pressure on aortic blood flow velocity and acceleration. Twenty-seven normal men were studied during various levels of lower body negative pressure (0 to -60 mm Hg) during which echocardiographic, Doppler and hormonal measurements were obtained. Lower body negative pressure induced a decrease in left ventricular diastolic diameter from 5.18 +/- 0.08 to 4.41 +/- 0.1 cm (p less than 0.0001) and in left ventricular systolic diameter from 3.33 +/- 0.09 to 2.84 +/- 0.1 cm (p less than 0.0001). Shortening fraction remained unchanged. The decrease in diastolic diameter resulted in a reduction in flow velocity integral from 13.8 +/- 0.8 to 7.5 +/- 0.4 cm (p less than 0.0001) and, therefore, in stroke volume from 89.6 +/- 4.7 to 49.5 +/- 2.8 ml (p less than 0.0001). Heart rate reflexly increased from 62.5 +/- 1.9 to 82.2 +/- 2.3 beats/min (p less than 0.0001) as did systemic vascular resistance from 1,280.8 +/- 69.5 to 1,863.4 +/- 121.4 dyne.s.cm-5 (p less than 0.0001). The increase in heart rate was insufficient to maintain cardiac output, which decreased from 5.53 +/- 0.29 to 3.99 +/- 0.21 liters/min (p less than 0.0001). Systolic, diastolic and mean arterial blood pressure was maintained. The negative pressure resulted in a concomitant significant increase in norepinephrine levels from 1.46 +/- 0.09 to 2.056 +/- 0.2 nmol/liter (p = 0.0019) but no change in plasma epinephrine: 0.845 +/- 0.22 to 0.78 +/- 0.11 nmol/liter (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic factors in patients dying of well-differentiated thyroid cancer

While some well-differentiated cancers of the thyroid gland are unusually aggressive, most have a more benign clinical behavior, making it difficult to evaluate factors possibly influencing patient survival such as initial surgical treatment. By studying 135 patients who received their initial surgical therapy at our institution, we have defined the prognostically significant factors. Sixteen patients (11.9%) died of disease during a ten- to 20-year follow-up period. Significant factors associated with death from disease were aged 40 years or older, primary lesion size of 2.5 cm or greater, presence of invasive characteristics, and presence of distant metastases. We recommend total thyroidectomy and postoperative sodium iodide I 131 therapy in patients 40 years of age or older, while suggesting a less aggressive approach may be appropriate in the younger patients.

Role of beta-lactamase and different testing conditions in oxacillin-borderline-susceptible staphylococci

A group of staphylococcal isolates for which oxacillin MICs were intermediate (1 to 4 micrograms/ml) were studied to establish the role of beta-lactamase in this phenomenon. MICs and MBCs of oxacillin and penicillin with and without clavulanic acid or sulbactam (4 or 16 micrograms/ml, respectively) were determined for 11 Staphylococcus aureus and 2 coagulase-negative Staphylococcus isolates for which oxacillin MICs were 1 to 4 micrograms/ml. The susceptibility studies were done with incubation at 35 and 30 degrees C, and the MICs were read at 24 and 48 h. Of the 13 isolates, 4 became resistant when longer incubation or 30 degrees C incubation was used, and the MICs for 9 remained in the intermediate range. Only three of these strains were susceptible to penicillin, and beta-lactamase was not detected. For 6 of 10 beta-lactamase-positive strains, there was a greater-than-twofold-dilution reduction in oxacillin MICs with the addition of clavulanic acid or sulbactam. Of the four strains that became resistant with incubation at the lower temperature, a clavulanic acid effect was observed in three but only at 35 degrees C. The oxacillin MIC for one of the beta-lactamase-negative strains was also reduced with clavulanic acid; however, this strain was inhibited by 1 microgram of clavulanic acid per ml alone. Bactericidal activity was observed with two or four times the oxacillin MIC in eight strains tested at both temperatures, and the combination with clavulanic acid was bactericidal at higher than four times the MIC in five of the strains at 30 degrees C. Our results suggest that oxacillin intermediate MICs for staphylococcal isolates are due not only to beta-lactamase hyperproduction but also some other unidentified factor. The reduction in oxacillin MIC observed when clavulanic acid was added to one strain was probably due to the intrinsic inhibitory activity of clavulanic acid.

Gastrointestinal bleeding after craniotomy: a retrospective review of 518 patients

A retrospective review of the medical records of 518 patients who underwent craniotomy over a 3 year interval was carried out to determine the rate of gastrointestinal bleeding and its relationship to the Glasgow Coma Score. There were 288 [55.5%] males and 230 [44.5%] females in the series; the mean age was 51.5 +/- 18.9 years. Forty percent had brain tumours, 18% had subarachnoid hemorrhage, 14% had spontaneous intracerebral hemorrhage, 19% had head injury and 8% had other diagnoses. Forty-eight [9.3%] of the patients had significant gastrointestinal bleeding, the distribution of which was as follows: hematemesis [37/518], melena [11/518] and/or hematochezia [4/518]. A further 51 [9.8%] had evidence of "coffee ground emesis" only. Of those with a Glasgow Coma Score of less than 10, 21% had significant GI bleeding while only 7% of patients with a Glasgow Coma Score greater than 10 had such a bleed [p less than 0.005]. Further analysis showed that the incidence of GI bleeding in patients who underwent craniotomy increased with decreasing GCS. GI bleeding did not correlate with age, sex, steroid administration or casual use of anti-ulcer medication.

[Immunopathological complications in enteric yersiniosis: incidence and serological diagnosis (author's transl)]

Using the Widal reaction, significant titres against Yersinia enterocolitica, O-group I and V, were found in 300 of 2843 patients (10.5%) with reactive arthritis or arthralgia, and in 38 (1.3%) against Y. pseudotuberculosis type I to V. Of 510 patients with erythema nodosum 86 (16.9%) and 30 (5.9%), respectively, had significant agglutinin titres against one or the other. The results confirm the aetiological significance of Y. pseudotuberculosis, type I to V, in reactive arthritis and erythema nodosum, as well as the essential saturation of patient sera especially with Salmonella of the B or D group in the demonstration of significant antibody titres against Y. pseudotuberculosis, type II and IV. Complement-fixation tests cannot be recommended for the diagnosis of enteric Yersiniosis and its complications. Only in 201 of 554 serum samples (36.3%) with significant agglutinin titres against Y. enterocolitica O-group I and V (0 : 3 and 0 : 9 after Winblad) did the results of the Widal reaction and the microcomplement-fixation reaction agree, titres apart.