Mode structure of coupled L3 photonic crystal cavities.

We investigate the energy splitting, quality factor and polarization of the fundamental modes of coupled L3 photonic crystal cavities. Four different geometries are evaluated theoretically, before experimentally investigating coupling in a direction at 30◦ to the line of the cavities. In this geometry, a smooth variation of the energy splitting with the cavity separation is predicted and observed, together with significant differences between the polarizations of the bonding and anti-bonding states. The controlled splitting of the coupled states is potentially useful for applications that require simultaneous resonant enhancement of two transitions.

Salmonella typhimurium initiates murine infection by penetrating and destroying the specialized epithelial M cells of the Peyer's patches.

Salmonella species are known to initiate infection of mammalian hosts by penetrating the intestinal epithelium of the small bowel. These bacteria preferentially interact with Peyer's patches which are collections of lymphoid follicles making up the gut-associated lymphoid tissue. We infected murine ligated intestinal loops with invasive and noninvasive Salmonella typhimurium strains for 30, 60, 120, and 180 min and examined the infected tissue by transmission electron microscopy. Within 30 min, we found that invasive S. typhimurium exclusively entered M cells found within the follicle-associated epithelium (FAE) of the Peyer's patches. Initially, interactions between invasive bacteria and enterocytes adjacent to the M cells were not found. Invasion of M cells was associated with the ability of the bacteria to invade tissue culture cells. S. typhimurium mutants, which were noninvasive for tissue culture cells, could not be found in ligated loops associated with M cells or enterocytes after incubations of 30, 60, 120, or 180 min. At 60 min, internalized invasive S. typhimurium were cytotoxic for the M cells. Destruction of an M cell formed a gap in the FAE which allowed organisms to invade enterocytes adjacent to the dead cell. Later in the infection process (120 and 180 min), the presence of bacteria beneath the FAE correlated with changes in the cytoarchitecture of the lymphoid follicle. In addition, replicating Salmonella began to enter both the apical and basolateral surfaces of enterocytes adjacent to infected M cells.

Splitting and lasing of whispering gallery modes in quantum dot micropillars.

We have studied the whispering gallery mode (WGM) resonances of GaAs/AlGaAs microcavity pillars containing InAs quantum dots. High quality factor WGMs are observed from a wide range of pillars with diameters from 1.2 to 50 µm. Multimode lasing with sub-milliwatt thresholds and high beta-factors approaching unity is observed under optical pumping in a 4 µm diameter pillar. Mode splitting is observed in WGMs from pillars with diameters of 5 µm, 20 µm and 50 µm.We develop a model in which the mode splitting in the larger pillars is caused by resonant scattering from the quantum dots themselves. The model explains why splittings are observed in all of the larger pillars and that the splitting decreases with increasing wavelength. Numerical simulations by COMSOL confirm that the model is plausible. This mechanism of splitting should be general for all circular resonant structures containing quantum dots such as microdisks, rings, toroids, and microspheres.

Polarized quantum dot emission from photonic crystal nanocavities studied under moderesonant enhanced excitation.

We study the linear polarization of the emission from single quantum dots embedded in an "L3" defect nanocavity in a two-dimensional photonic crystal. By using narrow linewidth optical excitation in resonance with higher-order modes, we are able to achieve strong quantum dot emission intensity whilst reducing the background from quantum dots in the surrounding lattice. We find that all the dots observed emit very strongly linearly polarized light of the same orientation as the closest mode, despite the fact that these quantum dots may be spectrally detuned by several times the mode linewidth. We discuss the coupling mechanisms which may explain this behavior.

Neuropsychological change in early phase schizophrenia during 12 months of treatment with olanzapine, risperidone, or haloperidol. The Canadian Collaborative Group for research in schizophrenia.

BACKGROUND: The purpose of this investigation was to test the efficacy of novel antipsychotic medications in the treatment of cognitive impairment in early phase schizophrenia. METHODS: Sixty-five patients in this multicenter double-blind study were randomly assigned to olanzapine (5-20 mg), risperidone (4-10 mg), or haloperidol (5-20 mg). Standard measures of clinical and motor syndromes were administered, as well as a comprehensive battery of tests to assess (1) motor skills, (2) attention span, (3) verbal fluency and reasoning, (4) nonverbal fluency and construction, (5) executive skills, and (6) immediate recall at baseline and after 6, 30, and 54 weeks of treatment. RESULTS: The general cognitive index derived from the 6 domain scores revealed a significantly greater benefit from treatment with olanzapine relative to haloperidol and olanzapine relative to risperidone, but no significant difference was shown between risperidone and haloperidol. The improvement related to olanzapine was apparent after 6 weeks and enhanced after 30 and 54 weeks of treatment. Exploratory within-group analyses of the 6 cognitive domains after a conservative Bonferroni adjustment revealed a significant improvement with olanzapine only on the immediate recall domain, and similar analyses of the 17 individual tests revealed a significant improvement with olanzapine only on the Hooper Visual Organization Test. CONCLUSIONS: These data suggest that olanzapine has some superior cognitive benefits relative to haloperidol and risperidone. A larger sample replication study is necessary to confirm and generalize the observations of this study and begin evaluation of the implications of this change to cerebral function and quality of life for people with schizophrenia.

Neuroleptic-induced supersensitivity psychosis: clinical and pharmacologic characteristics.

Tardive dyskinesia is thought to result from neostriatal dopaminergic receptor supersensitivity induced by chronic treatment with neuroleptics. The authors suggest that dopaminergic supersensitivity also occurs in the mesolimbic region after chronic neuroleptic exposure, resulting in the development of a supersensitivity psychosis. Neuroleptic-induced supersensitivity psychosis is illustrated by data from 10 patients that demonstrate the syndrome's clinical and pharmacologic characteristics. An implication of neuroleptic-induced mesolimbic supersensitivity is that the tenaency toward psychotic relapse in such patients is determined by more than just the normal course of the illness.

Clonazepam in the treatment of recurrent symptoms of depression and anxiety in a patient with systemic lupus erythematosus.

A patient undergoing steroid therapy for systemic lupus erythematosus developed symptoms of depression and anxiety that did not respond to conventional drug therapy. A regimen of clonazepam, an anticonvulsant drug, did relieve the symptoms.

Fast-cycling bipolar disorder induced by withdrawal from long-term treatment with a tricyclic antidepressant.

A unipolar depressed patient developed a fast-cycling bipolar disorder on abrupt discontinuation of long-term treatment with a tricyclic antidepressant. The case illustrates the potential for drug withdrawal to induce mood disturbance that is more severe than the original illness.

Vitamin E in the treatment of tardive dyskinesia: a double-blind placebo-controlled study.

The authors compared vitamin E with placebo in a double-blind randomized crossover study of 27 patients with tardive dyskinesia. Each treatment period lasted for 6 weeks. Vitamin E showed no differences from placebo in the treatment of tardive dyskinesia.

Proliferation of wound derived capillary endothelial cells: young versus aged.

The objective of this study was to compare the proliferative potential of wound derived capillary endothelial cells (WCEC) from aged and young rats. Endothelial cells were isolated from subcutaneously implanted sponges in 2- and 24-month-old rats. The identity of the cells as endothelial was confirmed by staining for Ac-LDL uptake. Aged and young WCEC (20,000/well) were stimulated with increasing concentrations of fetal calf serum (0, 2.5, 5, 10 and 15%). The increase in cell number was determined with a Coulter counter. At all serum concentrations, the proliferative capacity of WCEC from aged rats was significantly higher than that of WCEC from young rats.

Age-related alterations in the morphology of femoral artery vasa vasorum in the rat.

The objective of this study was to explore any age-related morphological changes in the vasa vasorum of the rat femoral artery. Vascular corrosion casts were prepared from 2, 12 and 24-month-old rats. Examination of the casts with the scanning electron microscope revealed dramatic differences in the appearance of the vessels of young and aged rats. The vasa vasorum of 2-month-old rats consisted of a dense network of capillaries. These vessels were dramatically reduced in number by 12 months, and even fewer capillaries were present at 24 months. This reduction in capillary density is consistent with the observed age-related decreases in oxygen tension and may explain why the aged are more prone to atherosclerosis.

Withdrawal symptoms after long-term treatment with low-potency neuroleptics.

Twenty-six chronic schizophrenic outpatients receiving low-potency anticholinergic neuroleptics were switched over periods of up to 2 years to an equivalent dose of high-potency neuroleptics. Of these patients, 85% experienced withdrawal symptoms, mainly insomnia, anxiety, and tensional restlessness. Complete withdrawal of low-potency medication was achieved during the study period in 9 patients only. The mean duration of treatment with low-potency neuroleptics was 15 years and the mean dose was 147 mg chlorpromazine equivalents/day. It is suggested that new symptoms associated with withdrawal of low-potency neuroleptics may lead to overcompliance by patients and difficulty in achieving the minimum therapeutic dosage. Thus, low-potency neuroleptics would not appear suitable for the long-term treatment of most schizophrenic patients.

Psychiatric morbidity associated with early clinical diagnosis of Huntington disease in a predictive testing program.

Predictive testing for Huntington disease is now possible by using DNA markers close to the mutant gene. Such tests result in an increased or decreased risk estimate as to whether the person tested has inherited the mutant gene. Persons who already manifest subtle signs of the disease but see themselves as presymptomatic will also present to the preclinical testing programs. The authors report a severe psychiatric reaction to a positive clinical diagnosis of Huntington disease in a woman enrolled in a pilot preclinical program who had a history of psychiatric illness and hospitalizations. She is the only one of 60 persons currently enrolled in the program who has had a serious crisis. The authors demonstrate the need for readily available and ongoing counseling services for all persons participating in such a program.

Thrombosis: the major Hickman catheter complication in patients with solid tumor.

Major complications of Hickman catheter placement (thrombosis and infection) were determined in 168 patients with solid tumor (lung, 79; head and neck, 56; esophagus, 24; and miscellaneous, 9). Catheter-related thrombosis was clinically detected in 22 individuals and was detected at autopsy in six (total 17 percent). The 17 percent figure underestimates the true incidence of thrombosis since only 25 percent of study patients had autopsies. Patients with adenocarcinoma of the lung constituted a high risk group. Nine of 20 (45 percent) of these patients had thrombosis compared to 25, 9, and 16 percent of patients with squamous cell cancers of lung, head and neck and esophagus, respectively (p less than 0.002). Three patients with thrombosis had pulmonary emboli and two died. Thrombosis occurred despite daily heparin catheter flushing. INfections occurred in 11 patients. One had suspected endocarditis, one had a subcutaneous tunnel infection, and nine had exit site infections. All responded to local or systemic antibiotics. Better methods to prevent thrombosis are needed.

An open trial of the D1 antagonist SCH 39166 in six cases of acute psychotic states.

Six psychotic patients were included in a four-week study of the effects of the D1 selective antagonist SCH 39166 given as monotherapy. Four had a diagnosis of schizophrenia, and two suffered from a schizoaffective disorder. All presented with an acute psychotic exacerbation at the beginning of the trial. SCH 39166 was progressively increased from 50 mg/day to 600 mg/day. In the four schizophrenic patients, the BPRS worsened, and three out of the four failed to complete the study because of this. Three schizophrenic patients were aggressive or violent after abrupt discontinuation of treatment. In the two patients with schizoaffective disorder the BPRS improved during the trial, but they had an acute relapse immediately after treatment discontinuation. Extrapyramidal symptoms improved in three of the six patients, and worsened in one.

Tardive dysmentia : further comments.

The author distinguishes between the putative neuroleptic-induced disorders of tardive dysmentia and supersensitivity psychosis. The distinction is made with regard to clinical features, response to pharmacological intervention, and proposed etiologies. It is suggested that tardive dysmentia is due not to dopaminergic supersensitivity but to some other neurotoxic phenomenon associated with the use of neuroleptic drugs. The possibility that cholinergic mechanisms are involved in the tardive dysmentia syndrome is examined. Finally, the potential for such drug-induced disorders to confuse diagnosis is highlighted.

Identification and characterization of mutants with increased expression of hilA, the invasion gene transcriptional activator of Salmonella typhimurium.

Induction of invasion gene transcription and expression of the invasive phenotype of Salmonella strains are regulated by environmental conditions. Experimental evidence indicates that oxygen, pH, and osmotic conditions need to closely resemble those of the host intestinal lumen for invasion gene activation. The hilA gene, encoded on Salmonella pathogenicity island 1 (SPI-1), is a transcriptional activator which is required for invasion and whose expression is modulated by oxygen, pH, and osmolarity. Additionally, hilA is regulated by genetic elements encoded on SPI-1 (hilC/sirC/sprA and hilD), as well as by elements which reside outside of SPI-1 (phoP/phoQ and sirA), although how environmental signals modulate hilA is unknown. In an effort to further characterize the Salmonella invasion gene regulon, we have created and preliminarily characterized 18 Tn5 insertions which result in upregulation of a hilA::lacZY fusion. We have classified the mutations based on location and phenotype into three classes. Six class 1 and six class 2 mutants have insertions in SPI-1 near the invasion gene orgA or the invasion gene regulator hilD, respectively. Six class 3 mutants reside outside of SPI-1 in four different loci. The class 2 and 3 mutations induce overexpression of an episomal hilA::lacZY fusion and significantly increase S. typhimurium invasion of HEp-2 cells in a standard invasion assay. These data implicate new regions of SPI-1 as being involved in the regulation of invasion by S. typhimurium and identify new invasion gene regulators located outside of SPI-1.

Preparing and retaining rural physicians through medical education.

PURPOSE: To identify educational approaches that best prepare physicians for rural work and small-town living, and that promote longer rural practice retention. METHOD: In two mail surveys (1991 and 1996-97), the authors collected data from primary care physicians who had moved to rural practices nationwide from 1987 through 1990. A total of 456 eligible physicians responded to both surveys (response rate of 69.0%). The authors identified those features of the physicians' training that correlated with their self-reported preparedness for rural practice and small-town living, and with how long they stayed in their rural practices. Analyses controlled for six features of the physicians and their communities. RESULTS: The physicians' sense of preparedness for small-town living predicted their retention duration (hazard ratio, 0.74, p < .0001), whereas their preparedness for rural medical practice did not predict their retention duration after controlling for preparedness for small-town living (hazard ratio, 0.92; p = .27). For the physicians who had just finished their training, only a few features of their training predicted either rural preparedness or retention. Residency rural rotations predicted greater preparedness for rural practice (p = .004) and small-town living (p = .03) and longer retention (hazard ratio, 0.43, p = .003). Extended medical school rural rotations predicted only greater preparedness for rural practice (p = .03). For the physicians who had prior practice experience, nothing about their medical training was positively associated with preparedness or retention. CONCLUSION: Physicians who are prepared to be rural physicians, particularly those who are prepared for small-town living, stay longer in their rural practices. Residency rotations in rural areas are the best educational experiences both to prepare physicians for rural practice and to lengthen the time they stay there.

Complications and results of phacoemulsification performed by residents.

The use of phacoemulsification by ophthalmic surgeons has increased markedly over the past five years. Previous studies have reported relatively high rates of vitreous loss by residents learning phacoemulsification. We retrospectively analyzed the complications and results in 300 cases of phacoemulsification with intraocular lens implantation performed by residents. The first 40 cases done by four residents in their second year of training were compared with approximately the last 40 cases done by each resident at the end of the third year. The overall rate of surgical complications was 6.3%, and the total rate of vitreous loss was 3.3%. The rate of surgical complications during the initial surgeries in the second year of residency was 9.3%; it was 3.3% by the end of the third year. The rate of vitreous loss was 5.3% in the second year and 1.3% during the third year. Postoperatively, 90.6% of all eyes had a final best corrected visual acuity of 20/40 or better (95% excluding patients with pre-existing ocular disease). With proper training and supervision, the rate of surgical complications for residents learning phacoemulsification is acceptably low when compared with the rate of extracapsular cataract extraction.

Simultaneous chemotherapy and radiotherapy with escalating doses of chemotherapy in patients with advanced esophageal carcinoma.

From January 1992 to January 1995, 39 patients were diagnosed with esophageal carcinoma at the Department of Veterans Affairs Medical Center in Washington, D.C. All of the patients were men aged 44 to 78, and the median age was 66. Staging included a physical examination, serum chemistries, barium swallow, endoscopy with biopsy, and computed tomographic scans of the chest and abdomen. Seven patients were ineligible for the study because they had poor performance status, refused treatment, or received treatment at another medical center. All the patients treated had a performance status of 1 to 2. In 1992, 15 patients received 400 mg/m2/d 5-fluorouracil; in 1993, eight patients received 500 mg/m2/d 5-fluorouracil; and in 1994, nine patients received 600 mg/m2/d 5-fluorouracil as a continuous intravenous infusion during radiotherapy, which consisted of 60 Gy over 6 to 8 weeks. The complete response rates were 26%, 25%, and 22% for 1992, 1993, and 1994, respectively. The median survival was 11 months, 14 months and 9 months for those same years, respectively. The major toxicities were hematologic. Three patients died of pneumonia during treatment. Simultaneous chemotherapy and radiotherapy is an effective mode of therapy for localized esophageal carcinoma. However, escalating doses of chemotherapy did not increase the complete response rate.