Polymerase chain reaction for diagnosis of genital herpes in a genitourinary medicine clinic

BACKGROUND: Polymerase chain reaction (PCR) has well established advantages over culture for diagnosis of herpes viruses, but its technical complexity has limited its widespread application. However, recent methodological advances have rendered PCR more applicable to routine practice. Aim: To compare automated PCR with viral culture for diagnosis of genital herpes. METHODS: We studied 236 patients presenting with clinical features suggestive of genital herpes at an inner city genitourinary medicine clinic. Two swabs were taken from each patient. Cell culture and typing were performed by standard methods. Automated PCR was performed using the LightCycler instrument and the infecting viral type was determined by restriction endonuclease digestion of amplicons. RESULTS: 109 patients (46%) had a positive test for herpes simplex virus (HSV). In 88, both PCR and culture were positive; in 21 PCR only was positive. With both detection methods, lesion duration and morphology were associated with HSV detection. Compared with culture alone, use of PCR increased sensitivity by 13.3% in specimens from vesicular lesions, by 27.4% from ulcerative lesions, and by 20.0% from crusting lesions. CONCLUSIONS: We advocate adoption of automated PCR as an efficient HSV detection and typing method for diagnosis of genital herpes in routine clinical practice. PCR allowed rapid laboratory confirmation of the diagnosis and increased the overall HSV detection rate by 24%.     

Microtubule reassembly in surface-activated platelets

It is generally accepted that a circumferential microtubule supports the discoid shape of resting platelets. The fate of the many-coiled polymer following platelet activation, however, has been a subject of considerable debate. Morphological investigations have suggested that the circumferential coils are constricted into tight rings around centrally concentrated organelles during platelet shape change. Biochemical studies employing colchicine-binding assays, on the other hand, have indicated that the bundle of microtubules dissolves almost completely within seconds after activation and reassembles in a new location one to four minutes later. The present study has accepted the latter hypothesis in order to examine the second part of the disassembly-reassembly theory proposed in biochemical studies. Platelets exposed to low temperatures sufficient to remove all microtubules were placed on glass slides and microscope grids to cause surface activation during rewarming. The combined stimuli of rewarming and surface activation might have been expected to cause more rapid assembly than warming alone or activation alone. This was not the case. Reassembly of microtubules during rewarming and simultaneous surface activation was not accelerated. In contrast to the constriction of microtubule rings observed during activation in control platelets, the diameters of coils that developed in chilled platelets one to two hours after rewarming and surface activation were twice those of control cells.     

Regenerative peripheral nerve interfaces for real-time,proportional control of a Neuroprosthetic hand

Introduction

Regenerative peripheral nerve interfaces (RPNIs) are biological constructs which amplify neural signals and have shown long-term stability in rat models. Real-time control of a neuroprosthesis in rat models has not yet been demonstrated. The purpose of this study was to: a) design and validate a system for translating electromyography (EMG) signals from an RPNI in a rat model into real-time control of a neuroprosthetic hand, and; b) use the system to demonstrate RPNI proportional neuroprosthesis control.

Methods

Animals were randomly assigned to three experimental groups: (1) Control; (2) Denervated, and; (3) RPNI. In the RPNI group, the extensor digitorum longus (EDL) muscle was dissected free, denervated, transferred to the lateral thigh and neurotized with the residual end of the transected common peroneal nerve. Rats received tactile stimuli to the hind-limb via monofilaments, and electrodes were used to record EMG. Signals were filtered, rectified and integrated using a moving sample window. Processed EMG signals (iEMG) from RPNIs were validated against Control and Denervated group outputs.

Results

Voluntary reflexive rat movements produced signaling that activated the prosthesis in both the Control and RPNI groups, but produced no activation in the Denervated group. Signal-to-Noise ratio between hind-limb movement and resting iEMG was 3.55 for Controls and 3.81 for RPNIs. Both Control and RPNI groups exhibited a logarithmic iEMG increase with increased monofilament pressure, allowing graded prosthetic hand speed control (R²?=?0.758 and R²?=?0.802, respectively).

Conclusion

EMG signals were successfully acquired from RPNIs and translated into real-time neuroprosthetic control. Signal contamination from muscles adjacent to the RPNI was minimal. RPNI constructs provided reliable proportional prosthetic hand control.

     

Tibolone and its metabolites induce antimitogenesis in human coronary artery smooth muscle cells: role of estrogen, progesterone, and androgen receptors

Tibolone, a hormone replacement drug, protects postmenopausal women against osteoporosis and climacteric symptoms without inducing adverse effects on the endometrium and breast. Compared with other estrogens, little is known about the cardiovascular effects of tibolone. Because abnormal growth of smooth muscle cells (SMCs) is a prerequisite for coronary artery disease, here we investigated the effects of tibolone on SMC growth. We examined the effects of tibolone and its metabolites on human arterial SMC growth (DNA synthesis, cellular proliferation, cell migration, collagen synthesis) and MAPK expression. Fetal calf serum-induced SMC growth, phosphorylated MAPK expression, and platelet-derived growth factor-induced SMC-migration were concentration-dependently inhibited by tibolone and its endogenous estrogenic and progestogenic/androgenic metabolites in the following order of potency: Delta 4-tibolone>3 beta-OH-tibolone congruent with 3 alpha-OH-tibolone. The antimitogenic effects of tibolone were partially blocked by ER antagonist (ICI182780), progesterone receptor antagonist (RU486) but not by the androgen receptor antagonist (flutamide); moreover, RU486 was more potent than ICI182780. The antimitogenic effects of tibolone were completely blocked by RU486 plus ICI182780. In addition, the inhibitory effects of equimolar concentrations of the three tibolone metabolites summed up to the inhibitory effects of tibolone. In conclusion, tibolone inhibits SMC growth and MAPK phosphorylation via both its estrogenic and progestogenic metabolites, and these inhibitory effects involve both progesterone and ERs. Hence, tibolone may induce antivasoocclusive actions and protect women against coronary artery disease.     

Effect of ventilation by high-frequency oscillation on lung and chest wall mechanics in the dog

High-frequency oscillation (HFO) has been shown to be effective in maintaining gas exchange, but the effects of high-frequency, small-volume ventilation on the mechanical properties of the respiratory system are unknown. A volume displacement plethysmograph was used to study lung volumes and static pressure-volume (PV) curves during HFO in pentobarbital-anesthetized dogs. During long-term studies, adequate gas exchange was maintained with a stroke volume of 2.5 ml/kg and frequencies between 15 and 30 Hz. The effect of 5–7 hours of HFO on lung and chest wall mechanics was studied in 8 dogs. In another 8 dogs the relationship of volume history and respiratory muscle tone to occlusion airway pressure and lung volume during short-term HFO was investigated. With prolonged HFO, a small but significant decrease in total lung capacity occurred by 5 hours and the static respiratory system PV curve shifted slightly to the right. These changes were reversed by muscle paralysis and may be explained by a change in respiratory muscle tone. Static lung compliance and the hysteresis ratio (an index of tissue properties) remained unchanged. The relationship of occlusion airway pressure and lung volume during short-term HFO was dependent on the lung volume history and was influenced by respiratory muscle tone only at low airway pressures. These findings suggest that during prolonged HFO a small increase in chest wall stiffness may result. However, occlusion airway pressure and lung volume at the onset of HFO are mainly dependent on the volume history of the lung. Presented in part at the Fall Meeting of the American Physiological Society, Toronto, Canada, October 12–17, 1980     

A novel method for evaluating the antimicrobial activity of tuberculosis treatment regimens.

OBJECTIVE: To evaluate the clinical response to antituberculosis chemotherapy rapidly. METHOD: Sputum viable counts from a previously published clinical trial comparing a standard regimen and one containing isoniazid, rifampicin and ciprofloxacin were re-evaluated using an exponential decay model. The results were fitted to a one or two phase exponential decline. The decline in viable counts followed a curve described by a single-phase exponential decay model. From these data the time taken to reduce the viable count by 50% (vt50) was calculated to estimate the bactericidal effect of the regimens. RESULTS AND CONCLUSION: This method shows promise as a means for early identification of patients who are responding poorly as a result of resistance or poor immune response and for comparing anti-tuberculosis regimens in clinical trials. The failure to show a two-phase exponential decay curve suggested that either the sputum does not contain bacteria upon which only drugs with a sterilising activity act or that they are not present in sufficient numbers to have a significant impact on the total viable count. Further studies are required to understand the physiological state of organisms being sampled in sputum.