The Rapid Growth of Burkitt Lymphoma Causing Partial Small Bowel Obstruction

Burkitt lymphoma (BL) is a neoplasm of the lymphoid tissue and one of the most prevalent malignancies worldwide. Classically, these patients present with unregulated B-cell differentiation causing fever, chills, night sweats, and weight loss. Although more common in children, in sporadic Burkitt lymphoma, symptoms often can be present in the abdomen. These patients also additionally report nausea, vomiting, and abdominal distention, which in rare instances can cause small bowel obstruction (SBO). Early detection and the initiation of chemotherapy remain highly effective in providing adequate care. This provides better outcomes and prevents surgical management.

Fibrosing mediastinitis resulting in unilateral pulmonary artery hypertension

Fibrosing mediastinitis (FM), a rare disorder that is further classified as excessive fibrous tissue that occurs within the mediastinum. Classically, presenting with manifestations dependent on where the fibrous tissue is located. In rare instances, compression of pulmonary vasculature can lead to Pulmonary Hypertension. Pulmonary Hypertension- Fibrosing Mediastinitis (PH-FM) represents a rare complication with minimal available data on incidence. In regards to all-cause mortality, no specific data regarding the prognosis of PH-FM exist. With the scarcity of data, this case aids in the advancement of literature due to unique unilateral obstruction and the need for further analysis on our current treatment.

Sarcoid-like reaction in malignant melanoma exacerbated with pembrolizumab therapy case report

Sarcoid Like Reaction (SLR) is a localized non-caseating epithelioid granulomatous reaction seen secondary to certain immunotherapies and malignancies. Invasive melanoma, while being associated with onset of sarcoidosis, has not shown to directly induce SLR in the literature. We present the case of a 68-year-old male with malignant melanoma, who was found to have SLR prior to starting immunotherapy, which worsened while on pembrolizumab. This case highlights the challenge of distinguishing between drug-induced SLR and melanoma-induced SLR, and the implications in terms of management.

The Challenges of Diagnosing Tuberculous Meningitis and Importance of Early Intervention

Background

Reported is a patient found to have miliary TB seeding the lungs and brain with CNS involvement resulting in tuberculous meningitis (TBM). False security in laboratory studies that lack adequate sensitivity resulted in delay of therapy which may have negatively impacted the patient's outcome. This case report aims to emphasize the importance of early initiation of therapy when clinical suspicion remains high despite initially negative diagnostic studies.

Case presentation

52 year old female originally from Guatemala presented headache, neck pain, vomiting and photophobia. CT of the chest showed numerous submillimeter sized bilateral lung nodules, with scattered calcifications. IGRA of the serum, sputum Acid Fast Bacillus (AFB) stain and culture and CSF AFB stain and culture were obtained and were all initially negative. Clinical suspicion for tuberculous meningitis remained high and RIPE therapy and methylprednisolone were started. CSF AFB culture was found positive for MTB. Despite therapy, patient continued to clinically decline with poor overall prognosis.

Conclusion

Early diagnosis and initiation of therapy is paramount in improving outcomes in TBM. Unfortunately, the available diagnostic tests lack adequate sensitivity to confidently rule out disease. False negative results can delay therapy and worsen clinical outcomes. Early identification often relies on history, evaluation of risk factors, in conjunction with corresponding labs and imaging findings. If clinical suspicion is high, empiric therapy should be initiated early. Infectious disease consultation is often indicated to further assist with diagnosis and management.

Concomitant Treatment of Tuberculosis and Hepatitis C Virus in Coinfected Patients Using Serum Drug Concentration Monitoring

Background

Concern for drug-drug interactions leading to treatment failure and drug-resistant strains have discouraged clinicians from attempting concomitant treatment of hepatitis C virus (HCV) and tuberculosis (TB). Increased metabolism of direct-acting antivirals (DAAs) by rifamycins has hindered concurrent use. Development of an assay for ledipasvir and sofosbuvir (LDV/SOF) serum concentrations for therapeutic drug monitoring (TDM) can ensure adequate therapy. We present the first cases of concomitant therapy of active TB and HCV with rifamycin-containing regimens and DAAs using TDM.

Methods

Using TDM, we aim to determine whether concomitant therapy with rifamycin-containing regimens and DAAs is safe and effective for patients coinfected with TB and HCV. Five individuals with TB and HCV who experienced transaminitis before or during TB therapy were concomitantly treated with rifamycin-containing regimens and LDV/SOF. Therapeutic drug monitoring was performed for LDV, SOF, and rifabutin during therapy. Baseline laboratory tests and serial liver enzymes were performed. Hepatitis C virus viral load and mycobacterial sputum cultures were obtained upon completion of therapy to determine efficacy of therapy.

Results

All patients were found to have nondetectable HCV viral loads and negative mycobacterial sputum cultures upon completion of therapy. No clinically significant adverse effects were reported.

Conclusions

These cases illustrate concomitant use of LDV/SOF and rifabutin in patients with HCV/TB coinfection. Utilizing serum drug concentration monitoring to guide dosing, correction of transaminitis were achieved, which allowed the use rifamycin-containing TB therapy. These findings suggest that concomitant therapy of TB/HCV is possible, safe, and effective.

Spontaneous Hemorrhage of Thoracic Cavernous Malformation Leading to Bilateral Lower Extremity Paralysis

Cavernous malformations (CMs) are abnormal clusters of thin-walled blood vessels located in the central nervous system. An 87-year-old male with a history of heart failure with reduced ejection fraction, coronary artery disease, and atrial fibrillation on rivaroxaban was admitted for acute onset, bilateral lower extremity weakness. He was found to have hemorrhagic transformation of a pre-existing spinal cord cavernous malformation located at the level of T9 of the thoracic column worsened by his use of anticoagulation. Surgical resection remains the only definitive management. Patients at high risk for surgical intervention are managed with supportive care and physical therapy.

Symmetric Ascending Paralysis Secondary to West Nile Virus

West Nile virus (WNV) is classified as a Flavivirus, belonging to a Japanese encephalitis subgroup often transmitted via mosquitoes. The classic presentation of a WNV infection usually displays high fevers, myalgias, and headache which can progress to neck stiffness, stupor, and coma (Case Rep Infect Dis. 2020;2020:6501658). Our case study presented with a rare manifestation of ascending paralysis, encompassing the feared neuroinvasive disease pattern that is seldom exhibited. This case had an unusual presentation as certain manifestations experienced by our patient closely resembled that of Guillain-Barré syndrome, although others were more indicative of poliomyelitis-like syndrome. Overall, the mainstay of therapy in both conditions is supportive care, although the prognosis varies substantially depending on the underlying diagnosis.

Subdural hematoma expansion in relation to measured mean and peak systolic blood pressure: A retrospective analysis

Objective

Subdural hematomas (SDH) account for an estimated 5 to 25% of intracranial hemorrhages. Acute SDH occur secondary to rupture of the bridging veins leading to blood collecting within the dural space. Risk factors associated with SDH expansion are well documented, however, there are no established guidelines regarding blood pressure goals in the management of acute SDH. This study aims to retrospectively evaluate if uncontrolled blood pressure within the first 24 h of hospitalization in patients with acute SDH is linked to hematoma expansion as determined by serial CT imaging.

Methods

A single center, retrospective study looked at 1,083 patients with acute SDH, predominantly above age 65. Of these, 469 patients met the inclusion criteria. Blood pressure was measured during the first 24 h of admission along with PT, INR, platelets, blood alcohol level, anticoagulation use and antiplatelet use. Follow-up CT performed within the first 24 h was compared to the initial CT to determine the presence of hematoma expansion. Mean systolic blood pressure (SBP), peak SBP, discharge disposition, length of stay and in hospital mortality were evaluated.

Results

We found that patients with mean SBP <140 in the first 24 h of admission had a lower rate of hematoma expansion than those with SBP > 140. Patients with peak SBP > 200 had an increased frequency of hematoma expansion with the largest effect seen in patients with SBP > 220. Other risk factors did not contribute to hematoma expansion.

Conclusions

These results suggest that blood pressure is an important factor to consider when treating patients with SDH with medical management. Blood pressure management should be considered in addition to serial neurological exams, repeat radiological imaging, seizure prophylaxis and reversal of anticoagulation.

Applications of laser radiation pressure

Use of lasers has revolutionized the study and applications of radiation pressure. Light forces have been achieved which strongly affect the dynamics of individual small particles. It is now possible to optically accelerate, slow, stably trap, and manipulate micrometer-sized dielectric particles and atoms. This leads to a diversity of new scientific and practical applications in fields where small particles play a role, such as light scattering, cloud physics, aerosol science, atomic physics, quantum optics, and high-resolution spectroscopy.

Forces of a single-beam gradient laser trap on a dielectric sphere in the ray optics regime

We calculate the forces of single-beam gradient radiation pressure laser traps, also called "optical tweezers," on micron-sized dielectric spheres in the ray optics regime. This serves as a simple model system for describing laser trapping and manipulation of living cells and organelles within cells. The gradient and scattering forces are defined for beams of complex shape in the ray-optics limit. Forces are calculated over the entire cross-section of the sphere using TEM00 and TEM*00 mode input intensity profiles and spheres of varying index of refraction. Strong uniform traps are possible with force variations less than a factor of 2 over the sphere cross-section. For a laser power of 10 mW and a relative index of refraction of 1.2, we compute trapping forces as high as approximately 1.2 x 10(-6) dynes in the weakest (backward) direction of the gradient trap. It is shown that good trapping requires high convergence beams from a high numerical aperture objective. A comparison is given of traps made using bright field or differential interference contrast optics and phase contrast optics.

Optical trapping and manipulation of neutral particles using lasers

The techniques of optical trapping and manipulation of neutral particles by lasers provide unique means to control the dynamics of small particles. These new experimental methods have played a revolutionary role in areas of the physical and biological sciences. This paper reviews the early developments in the field leading to the demonstration of cooling and trapping of neutral atoms in atomic physics and to the first use of optical tweezers traps in biology. Some further major achievements of these rapidly developing methods also are considered.

Optical trapping and manipulation of neutral particles using lasers

The techniques of optical trapping and manipulation of neutral particles by lasers provide unique means to control the dynamics of small particles. These new experimental methods have played a revolutionary role in areas of the physical and biological sciences. This paper reviews the early developments in the field leading to the demonstration of cooling and trapping of neutral atoms in atomic physics and to the first use of optical tweezers traps in biology. Some further major achievements of these rapidly developing methods also are considered.

Fertilization of bovine oocytes induced solely with combined laser microbeam and optical tweezers

PURPOSE

Our purpose was to show that fertilization of oocytes can be obtained solely by laser light-mediated manipulation of gametes.

METHOD

A small channel was drilled into the zona pellucida of bovine oocytes using an ultraviolet (UV)-laser microbeam. Highly diluted cattle sperm were not able to fertilize the laser drilled oocytes.

RESULTS

Fertilization was achieved only when three to five cattle sperm were trapped with optical tweezers and inserted directly through the laser drilled hole into the perivitelline space. After 20 hr, 3 of 79 (3.8%) oocytes revealed two pronuclei and a sperm tail within their cytoplasm. Cattle sperm are difficult to catch. Therefore, the gametes had to remain for about 20 min in room atmosphere, which might be the reason for the low fertilization results.

CONCLUSIONS

The results indicate that a combined UV-laser microbeam and optical tweezers trap can be used successfully for "noncontact" microinsemination procedures.

Zona drilling and sperm insertion with combined laser microbeam and optical tweezers

A combined UV-laser microbeam and optical-tweezers trap was used to perform laser zona drilling and subzonal insemination in cattle. Using a precisely focused UV-laser microbeam, a small channel of about 10 microns in diameter was drilled into the zona pellucida. With a three-dimensional optical-tweezers trap, a single sperm was caught and transported through the laser-drilled hole directly into the perivitelline space. Furthermore, the sperm was brought into close contact with the oolemma to facilitate sperm-oocyte fusion. Using the laser-microscope system, noncontact, entirely sterile, and highly selective micromanipulation of gametes can be achieved with no need for mechanical microtools. Laser micromanipulation seems to be less detrimental to the gametes and is comparatively is easy to perform. Thus, the combined UV-laser microbeam and optical tweezers trap may be a helpful tool for IVF procedures.

The study of cells by optical trapping and manipulation of living cells using infrared laser beams

The new technique of optical trapping and manipulation of living cells using the forces of radiation pressure from infrared single beam gradient laser traps is reviewed. These traps, also referred to as "optical tweezers," are capable of stably trapping transparent micron and submicron biological particles free of optical damage. Entire cells or organelles within the interior of living cells can be manipulated without damaging the cell wall. The trap is built into a high resolution microscope for combined trapping and high resolution viewing. Experiments demonstrating reproduction of motile bacteria and yeast cells within infrared traps and manipulations of plant and animal cells are discussed. Applications to the study of the mechanical properties of cell cytoplasm, study of cell function, and cell separation and orientation are considered. The ability to apply controlled light forces on cells of magnitude comparable to or often much greater than gravity suggests that these optical techniques might have relevance to experiments showing the influence of gravity on cells.

Force generation of organelle transport measured in vivo by an infrared laser trap

Organelle transport along microtubules is believed to be mediated by organelle-associated force-generating molecules. Two classes of microtubule-based organelle motors have been identified: kinesin and cytoplasmic dynein. To correlate the mechanochemical basis of force generation with the in vivo behaviour of organelles, it is important to quantify the force needed to propel an organelle along microtubules and to determine the force generated by a single motor molecule. Measurements of force generation are possible under selected conditions in vitro, but are much more difficult using intact or reactivated cells. Here we combine a useful model system for the study of organelle transport, the giant amoeba Reticulomyxa, with a novel technique for the non-invasive manipulation of and force application to subcellular components, which is based on a gradient-force optical trap, also referred to as 'optical tweezers'. We demonstrate the feasibility of using controlled manipulation of actively translocating organelles to measure direct force. We have determined the force driving a single organelle along microtubules, allowing us to estimate the force generated by a single motor to be 2.6 x 10(-7) dynes.

Internal cell manipulation using infrared laser traps

The ability of infrared laser traps to apply controlled forces inside of living cells is utilized in a study of the mechanical properties of the cytoplasm of plant cells. It was discovered that infrared traps are capable of plucking out long filaments of cytoplasm inside cells. These filaments exhibit the viscoelastic properties of plastic flow, necking, stress relaxation, and set, thus providing a unique way to probe the local rheological properties of essentially unperturbed living cells. A form of internal cell surgery was devised that is capable of making gross changes in location of such relatively large organelles as chloroplasts and nuclei. The utility of this technique for the study of cytoplasmic streaming, internal cell membranes, and organelle attachment was demonstrated.

Optical trapping and manipulation of single cells using infrared laser beams

Use of optical traps for the manipulation of biological particles was recently proposed, and initial observations of laser trapping of bacteria and viruses with visible argon-laser light were reported. We report here the use of infrared (IR) light to make much improved laser traps with significantly less optical damage to a variety of living cells. Using IR light we have observed the reproduction of Escherichia coli within optical traps at power levels sufficient to give manipulation at velocities up to approximately 500 micron s-1. Reproduction of yeast cells by budding was also achieved in IR traps capable of manipulating individual cells and clumps of cells at velocities of approximately micron s-1. Damage-free trapping and manipulation of suspensions of red blood cells of humans and of organelles located within individual living cells of spirogyra was also achieved, largely as a result of the reduced absorption of haemoglobin and chlorophyll in the IR. Trapping of many types of small protozoa and manipulation of organelles within protozoa is also possible. The manipulative capabilities of optical techniques were exploited in experiments showing separation of individual bacteria from one sample and their introduction into another sample. Optical orientation of individual bacterial cells in space was also achieved using a pair of laser-beam traps. These new manipulative techniques using IR light are capable of producing large forces under damage-free conditions and improve the prospects for wider use of optical manipulation techniques in microbiology.

Optical trapping and manipulation of viruses and bacteria

Optical trapping and manipulation of viruses and bacteria by laser radiation pressure were demonstrated with single-beam gradient traps. Individual tobacco mosaic viruses and dense oriented arrays of viruses were trapped in aqueous solution with no apparent damage using approximately 120 milliwatts of argon laser power. Trapping and manipulation of single live motile bacteria and Escherichia coli bacteria were also demonstrated in a high-resolution microscope at powers of a few milliwatts.

Polarization-selective 3-dB fiber directional coupler

Measurements on a 3-dB polarization-selective fiber directional coupler demonstrate that the polarization selectivity arises from different mismatches for the propagation constants of the two polarizations.

Stable radiation-pressure particle traps using alternating light beams

A new type of stable alternating-beam light trap is proposed for confinement of neutral atoms and macroscopic dielectric particles. This trap, based only on the scattering force of radiation pressure, overcomes the limitations of the optical Earnshaw theorem. Trapping of ~10(7) sodium atoms in large volumes (100 cm(3)) seems possible with well depths >1 K and with optical cooling close to the Purcell limit of ~10(-4) K. Trapping at points of zero light intensity is considered.

In-line fiber-polarization-rocking rotator and filter

An in-line polarization rotator has been built into a single-mode birefringent fiber. The rotator utilizes periodic twists of the fiber's principal axes, which were formed by rocking the preform as the fiber was drawn. The polarization conversion between the principal axes is wavelength dependent, with a bandwidth inversely proportional to the number of twist periods. The bandwidth of the present rotator was 4.8 nm for 100% conversion in a fiber length of 170 cm.

Studies of self-focusing bistable devices using liquid suspensions of dielectric particles

We describe the results of experiments on bistable and multistable self-focusing devices using liquid suspensions of dielectric particles as the nonlinear medium. The nonlinear parameters for this medium are calculable from first principles. A simple model predicts regions of bistability and multistability that are in good agreement with the experimental observations.

Tension-adjusted in-line optical-fiber attenuator

We describe an in-line, single-mode fiber attenuator using a combination of polarization-preserving and single-polarization fibers. The attenuation is adjustable over a 30-dB range by varying the birefringence of a short lengthof fiber with tension. The insertion loss is 1.3 dB. The tension birefringence arises from the difference in Poisson's ratio between the noncircular stress cladding and the silica substrate glass.

Stability of radiation-pressure particle traps: an optical Earnshaw theorem

We prove an optical radiation Earnshaw theorem: A small dielectric particle cannot be trapped by using only the scattering force of optical radiation pressure. A corollary is that the gradient or dipole force is necessary to any successful optical trap. We discuss the implications of the theorem for recent proposals for the optical trapping of neutral atoms.

Simultaneous determination of refractive index and size of spherical dielectric particles from light scattering data

The diameter and refractive index of micrometer sized spherical dielectric particles are simultaneously deduced using the wavelength dependence of backscattering data from optically levitated particles. The accuracy of the results is set by experimental errors in the determination of the wavelength of backscatter resonance peaks and the ratio of slopes of specified peaks. At present the refractive index and diameter can be deduced with relative errors of 5 x 10(-5). This represents the most accurate determination of absolute size and refractive index yet made by light scattering. A reduction of these errors by an order of magnitude is possible. We assume a priori knowledge of diameter and refractive index with accuracy of 10(-1) and 5 x 10(-3), respectively.

Intensity discrimination of optical pulses with birefringent fibers

An intensity discriminator for optical pulses can be made with a birefringent fiber. Such a discriminator would be useful for separating the intense subpicosecond pulses formed by solitonlike compression from the weaker uncompressed background. The discriminator utilizes an intensity-dependent state of polarization out of the fiber.

Use of a liquid suspension of dielectric spheres as an artificial Kerr medium

We present the derivation of scaling relationships that describe the behavior of liquid suspensions of dielectric spheres as nonlinear optical media and report results of four-wave mixing experiments that are in good agreement with these predictions.

Continuous-wave self-focusing and self-trapping of light in artificial Kerr media

Artificial Kerr media made from liquid suspensions of submicrometer particles were used as a new type of nonlinear medium for observing cw self-focusing and self-trapping of laser beams. Self-trapping of TEM(00)-mode beams and higher-order TEM(01)- and TEM(01)* -mode beams were investigated. Saturation-free operation down to filament diameters of ~2 microm was observed. The independence of the critical power for self-trapping on the beam diameter in the unsaturated regime was confirmed for the first time to our knowledge. Values of the nonlinear coefficient were determined for a range of particle diameters from 0.038 to 0.234 microm.

Outer diameter measurement of low birefringence optical fibers by a new resonant backscatter technique

A new, highly precise, optical fiber outer diameter measuring technique based on near-field resonant backscattered light is described. Relative accuracies of +/-10(-2) microm were achieved in diameter measurements using Fabry-Perot resonances and +/-10(-3) microm in average diameter measurements using dielectric surface-wave resonances for ~100-microm fibers. The shape of a new type of low birefringence spun fiber, made by rapidly spinning a near circular preform in the pulling oven, was measured. We observed a small ellipticity which rotated helically along the fiber. The possibility of making absolute and real-time outer diameter measurements is discussed.

Four-wave mixing in an artificial Kerr medium

Degenerate four-wave mixing experiments have been performed using a liquid suspension of 0.234-microm-diameter latex spheres as the nonlinear medium. The measured effective optical Kerr coefficient, n(2), is 3.6 x 10(-3) (MW/cm(2))(-1). This is ~10(5)x the value for CS(2). Measured grating reflectivity, formation, and decay times are in reasonable agreement with a simple model assuming Rayleigh scattering and Brownian diffusion.

Observation of optical resonances of dielectric spheres by light scattering

Use of the wavelength and size dependence of light scattering from optically levitated liquid drops is demonstrated as a sensitive means of detecting optical resonances of dielectric spheres. High resolution spectra are presented of the radiation pressure, far- and near-field backscatter, and 90 degrees scatter. Excellent agreement is found between experimental spectra and high resolution Mie calculations of Chylek et al. Strong evidence supporting the van de Hulst dielectric surface-wave model for these resonances is presented. Use of resonances for high precision measurement of sphere size and sphere distortion, index of refraction, temperature, and vapor pressure is discussed.

Optical Kerr effect in long fibers

Optical Kerr modulation of >100% is demonstrated in long birefringent optical fibers using low laser powers of ~1 W. We have experimentally investigated the effects of group-velocity dispersion, thermal stability of polarization, and fiber birefringence. Use of fiber Kerr modulation as a fast optical shutter is studied, and it is concluded that resolution times shorter than 1 psec are possible in principle.

Observation of light scattering from nonspherical particles using optical levitation

The optical levitation technique has been extended to the study of light scattering from several basic types of nonspherical particles such as spheroids; spherical doublets, triplets, and quadruplets; and spheres within spheres. Individual particles were assembled in air using two independently maneuverable laser beams and then held at rest in the beam in fixed orientation. Observations were made of the light scattering in the near and far field with high resolution. Other applications of the technique are envisaged.

Cooling and trapping of atoms by resonance radiation pressure

The combined use of trapping and cooling laser beams for optical trapping and cooling of neutral atoms by the forces of resonance radiation pressure is examined. Calculations show that atoms can be held in traps as deep as 10(-4) eV at temperatures of ~10(-3) K, close to the minimum set by quantum fluctuations. Spatial confinement of atoms to a region a fraction of a wavelength in length should be possible.

Optical Levitation of Liquid Drops by Radiation Pressure

Charged and neutral liquid drops in the diameter range from 1 to 40 microns can be stably levitated and manipulated with laser beams. The levitation technique has been extended toward smaller particles (about 1 micron), lower laser power (less than 1 milliwatt), and deeper traps (greater than ten times the particle's weight). The techniques developed here have particular importance in cloud physics, aerosol science, fluid dynamics, and optics. The interactions of the drops with light, the electric field, the surrounding gas, and one another can be observed with high precision.