Methods for making and observing model lipid droplets

The mechanisms by which the lipid droplet (LD) membrane is remodeled in concert with the activation of lipolysis incorporate a complex interplay of proteins, phospholipids, and neutral lipids. Model LDs (mLDs) provide an isolated, purified system for testing the mechanisms by which the droplet composition, size, shape, and tension affects triglyceride metabolism. Described here are methods of making and testing mLDs ranging from 0.1 to 40 μm diameter with known composition. Methods are described for imaging mLDs with high-resolution microscopy during buffer exchanges for the measurement of membrane binding, diffusion, and tension via fluorescence correlation spectroscopy (FCS), fluorescence recovery after photobleaching (FRAP), fluorescence lifetime imaging microscopy (FLIM), atomic force microscopy (AFM), pendant droplet tensiometry, and imaging flow cytometry. These complementary, cross-validating methods of measuring LD membrane behavior reveal the interplay of biophysical processes in triglyceride metabolism.

Four-color fluorescence cross-correlation spectroscopy with one laser and one camera

The diffusion and reorganization of phospholipids and membrane-associated proteins are fundamental for cellular function. Fluorescence cross-correlation spectroscopy (FCCS) measures diffusion and molecular interactions at nanomolar concentration in biological systems. We have developed an economical method to simultaneously monitor diffusion and complexation with the use of super-continuum laser and spectral deconvolution from a single detector. Customizable excitation wavelengths were chosen from the wide-band source and spectral fitting of the emitted light revealed the interactions for up to four chromatically overlapping fluorophores simultaneously. This method was applied to perform four-color FCCS that we demonstrated with polystyrene nanoparticles, lipid vesicles, and membrane-bound molecules. Up to four individually customizable excitation channels were selected from the broad-spectrum fiber laser to excite the diffusers within a diffraction-limited spot. The fluorescence emission passed through a cleanup filter and a dispersive prism prior to being collected by a sCMOS or EMCCD camera with up to 1.8 kHz frame rates. The emission intensity versus time of each fluorophore was extracted through a linear least-square fitting of each camera frame and temporally correlated via custom software. Auto- and cross-correlation functions enabled the measurement of the diffusion rates and binding partners. We have measured the induced aggregation of nanobeads and lipid vesicles in solution upon increasing the buffer salinity. Because of the adaptability of investigating four fluorophores simultaneously with a cost-effective method, this technique will have wide application for examining macromolecular complex formation in model and living systems.

Four-color fluorescence cross-correlation spectroscopy with one laser and one camera

The diffusion and reorganization of phospholipids and membrane-associated proteins are fundamental for cellular function. Fluorescence cross-correlation spectroscopy (FCCS) measures the diffusion and molecular interactions at nanomolar concentration in biological systems. We have developed a novel, economical method to simultaneously monitor diffusion and oligomerization with the use of super-continuum laser and spectral deconvolution from a single detector. Customizable excitation wavelengths were chosen from the wide-band source and spectral fitting of the emitted light revealed the interactions for up to four spectrally overlapping fluorophores simultaneously. This method was applied to perform four-color FCCS, as demonstrated with polystyrene nanoparticles, lipid vesicles, and membrane-bound molecules. Up to four individually customizable excitation channels were selected from the broad-spectrum fiber laser to excite the diffusers within a diffraction-limited spot. The fluorescence emission passed through a cleanup filter and a dispersive prism prior to being collected by a sCMOS or EMCCD camera with up to 10 kHz frame rates. The emission intensity versus time of each fluorophore was extracted through a linear least-square fitting of each camera frame and temporally correlated via custom software. Auto- and cross-correlation functions enabled the measurement of the diffusion rates and binding partners. We have measured the induced aggregation of nanobeads and lipid vesicles in solution upon increasing the buffer salinity. Because of the adaptability of investigating four fluorophores simultaneously with a cost-effective method, this technique will have wide application for examining complex homo- and heterooligomerization in model and living systems.

1-[3-(2-Benz-yloxy-6-hy-droxy-4-methyl-phen-yl)-5-[3,5-bis-(tri-fluoro-meth-yl)phen-yl]-4,5-di-hydro-1H-pyrazol-1-yl]propane-1-one

In the title compound, C₂₈H₂₄F₆N₂O₃, the mean plane of the central pyrazoline ring forms dihedral angles of 2.08 (9) and 69.02 (16)° with the 2-benz­yloxy-6-hy­droxy-4-methyl­phenyl and 3,5-bis­(tri­fluoro­meth­yl)phenyl rings, respectively. The dihedral angle between the mean planes of the pyrazoline and 3,5-bis­(tri­fluoro­meth­yl)phenyl rings is 68.97 (9)°. An intra­molecular O—H⋯N hydrogen bond is observed, which forms an S(6) graph-set motif. In the crystal, pairs of weak C—H⋯F halogen inter­actions link the mol­ecules into inversion dimers while molecular chains along [100] are formed by C—H⋯O contacts.

3-(2-Chloro-3-hy-droxy-4-meth-oxy-phen-yl)-1-(4,5-dimeth-oxy-2-methyl-phen-yl)prop-2-en-1-one

The title compound, C(19)H(19)ClO(5), is a chloro derivative of a biologically significant chalcone family. The mean plane of the two substituted benzene rings are twisted by 55.33 (8)° with respect to each other. An intra-molecular C-H⋯Cl hydrogen bond generates an S(5) graph-set motif. In the crystal, a bifurcated O-H⋯(O,O) hydrogen bond leads to an R(1) (2)(5) graph-set motif and to the formation of zigzag chains propagating along the c-axis direction. A weak π-π inter-action involving the methyl-phenyl rings [centroid-centroid distance = 3.8185 (10) Å] and C-H⋯π inter-actions also occur.

Herpes simplex virus hepatitis: case report and review

Hepatitis is an unusual manifestation of herpesvirus infection. Herpes simplex virus hepatitis is a difficult diagnosis to establish, and the infection is often fatal. We report one case of herpes simplex virus hepatitis and review 51 cases in the literature. Impaired immunity resulting from pregnancy, malignancy, immunosuppression, or inhalational anesthetics may be predisposing factors. Fever, nausea, vomiting, abdominal pain, leukopenia, thrombocytopenia, coagulopathy, and a marked rise in serum transaminase levels are invariably present. Liver biopsy is the procedure of choice for diagnosis. The liver appears mottled and has a minimal inflammatory response. Mortality rates associated with herpes simplex virus hepatitis are high, and early diagnosis and treatment with acyclovir or vidarabine may produce a favorable outcome.

Surgical complications of gynecologic surgery

Complications of gynecological surgery are considerable and when reviewed in detail are almost frightening. There is no substitute for experience and intimate knowledge of the intricate pelvic structures in health and disease.Anyone who is active in the field is sooner or later going to experience some difficulty whether it be due to his miscalculation or to innate conditions in the patient which are beyond his/her control.It is the responsibility of the pelvic surgeon to recognize the complication and apply proper corrective measures. The patient should not be given false hopes of sure success nor should she be deprived of whatever hope for success does exist.