Sonography of intestinal abnormality in the right iliac fossa

The findings on sonographic examination of intestinal disorders in the right iliac fossa are often nonspecific. We have found the classification system just described useful because it leads to a meaningful differential diagnosis, which may be narrowed on the basis of various distinguishing features. The use of other imaging techniques, imaging-guided aspiration or biopsy, or surgical intervention may be necessary to make the exact diagnosis.     

Conopressin affects excitability, firing, and action potential shape through stimulation of transient and persistent inward currents in mulluscan neurons

The molluscan vasopressin/oxytocin-related neuropeptide conopressin activates two persistent inward currents in neurons from the anterior lobe of the right cerebral ganglion of Lymnaea stagnalis that are involved in the control of male copulatory behavior. The low-voltage-activated (LVA) current is activated at a wide range of membrane potentials, its amplitude being only weakly voltage dependent. The high-voltage-activated (HVA) current is activated at potentials positive to -40 mV only and shows a steep voltage dependence. Occurrence of both currents varies from cell to cell, some expressing both and others only the HVA current. In most neurons that have the LVA current, a conopressin-independent persistent inward current (INSR) is found that resembles the HVA current in its voltage dependence. The functional importance of the LVA and HVA currents was studied under current-clamp conditions in isolated anterior lobe neurons. In cells exhibiting both current types, the effect of activation of the LVA current alone was investigated as follows: previously recorded LVA current profiles were injected into the neurons, and the effects were compared with responses induced by conopressin. Both treatments resulted in a strong depolarization and firing activity. No differences in firing frequency and burst duration were observed, indicating that activation of the LVA current is sufficient to evoke bursts. In cells exhibiting only the HVA current, the effect of conopressin on the response to a depolarizing stimulus was tested. Conopressin reversibly increased the number of action potentials generated by the stimulus, suggesting that the HVA current enhances excitability and counteracts accommodation. Conopressin enhanced action potential broadening during depolarizing stimuli in many neurons. Voltage-clamp experiments performed under ion-selective conditions revealed the presence of transient sodium and calcium currents. Using the action potential clamp technique, it was shown that both currents contribute to the action potential. The calcium current, which is activated mainly during the repolarizing phase of the action potential, is augmented by conopressin. Thus conopressin may directly modulate the shape of the action potential. In summary, conopressin may act simultaneously on multiple inward currents in anterior lobe neurons of Lymnaea to affect firing activity, excitability, and action potential shape.     

Crystal structure of bacteriophage T4 deoxynucleotide kinase with its substrates dGMP and ATP

NMP kinases catalyse the phosphorylation of the canonical nucleotides to the corresponding diphosphates using ATP as a phosphate donor. Bacteriophage T4 deoxynucleotide kinase (DNK) is the only member of this family of enzymes that recognizes three structurally dissimilar nucleotides: dGMP, dTMP and 5-hydroxymethyl-dCMP while excluding dCMP and dAMP. The crystal structure of DNK with its substrate dGMP has been determined at 2.0 A resolution by single isomorphous replacement. The structure of the ternary complex with dGMP and ATP has been determined at 2.2 A resolution. The polypeptide chain of DNK is folded into two domains of equal size, one of which resembles the mononucleotide binding motif with the glycine-rich P-loop. The second domain, consisting of five alpha-helices, forms the NMP binding pocket. A hinge connection between the domains allows for large movements upon substrate binding which are not restricted by dimerization of the enzyme. The mechanism of active centre formation via domain closure is described. Comparison with other P-loop-containing proteins indicates an induced-fit mode of NTP binding. Protein-substrate interactions observed at the NMP and NTP sites provide the basis for understanding the principles of nucleotide discrimination.     

Entomological and rodent surveillance of suspected plague foci in agro-environmental and feral biotopes of a few districts in Maharashtra and Gujarat states of India

Studies carried out on entomological and rodent surveillance in agroclimatic and feral biotopes of five districts of Maharashtra and two districts of Gujarat revealed that the terrain features of the seven districts surveyed were conducive to wild rodent species, Tatera indica, a natural reservoir of plague and vector flea species, Xenopsylla cheopis. A total of 214 Tatera indica and three Bandicoota bengalensis were collected from burrows by the digging method and 89 rat fleas were retrieved. The flea index calculated ranged from 0.26 to 1.0 in different districts. The examination of blood serum samples, contact tissue impression smears and tissue organs (heart, lung, liver and spleen) of these wild rodents did not reveal any evidence of plague activity. The natural harbourages of Tatera indica were found to be elevated land or raised margins of agricultural fields or barren land with thorny bushes/xerophytic plants and parthenium grass. Agricultural fields having wet soil were found to be the preferred harbourages of Bandicoota bengalensis. Movement of wild rodents toward human settlement was observed to be the common phenomenon during the harvesting season which may lead to the creation of favorable conditions for plague outbreaks.     

A circadian rhythm of locomotor activity in newly emerged Ceratophyllus sciurorum

An amended version of the Short Form 36 health survey questionnaire (SF-36), which has been suggested as being more suitable for self-completion in older adults, was evaluated among a group of elderly subjects with Parkinson's disease (PD). In the subjects who were able to fully complete the modified SF-36 unaided, the severity of PD was broadly reflected by low reported levels of functioning and well-being with this measure. However, the modified questionnaire still did not overcome the problem of missing responses from elderly subjects. A total of 24% of respondents missed one or more of the 36 statements and 80% of missing responses were concentrated in the three statements which had been modified. The SF-36 in its original form would need to be combined with a disease-specific measure to adequately evaluate the health status of older adults with PD.     

Probing cellular protein targets of H2O2 with fluorescein-conjugated iodoacetamide and antibodies to fluorescein

Fatty acid ethyl ester synthase-III metabolizes both ethanol and carcinogens. Structure-function studies of the enzyme have not been performed in relation to site specific mutagenesis. In this study, three residues (Gly 32, Cys 39 and His 72) have been mutated to observe their role in enzyme activity. Gly to Gln, Cys to Trp and His to Ser mutations did not affect fatty acid ethyl ester synthase activity, but His to Ser mutant had less than 9% of control glutathione S-transferase activity. The apparent loss of transferase activity reflected a 28 fold weaker binding constant for glutathione. Thus, this study indicates that Gly and Cys may not be important for synthase or transferase activities however, histidine may play a role in glutathione binding, but it is not an essential catalytic residue of glutathione S-transferase or for fatty acid ethyl ester synthase activity.     

Effect of flow on first-pass metabolism of drugs: single pass studies on 4-methylumbelliferone conjugation in the serially perfused rat intestine and liver preparations

Intracellular in vivo recordings of physiologically identified inferior colliculus central nucleus (ICc) auditory neurons (n = 71) were carried out in anesthetized guinea pigs. The neuronal membrane characteristics are described showing mainly quantitative differences with a previous report [Nelson, P.G. and Erulkar, S.D., J. Neurophysiol., 26 (1963) 908-923]. The spontaneous spike activity was consistent with the discharge pattern of most extracellularly recorded units. The action potentials showed different spike durations, short and long, and some of them exhibited hyperpolarizing post-potentials. There were also differences in firing rate. The ICc neurons exhibited irregular activity producing spike trains as well as long silent periods (without spikes). Intracellular current injection revealed membrane potential adaptation and shifts that outlasted the electrical stimuli by 20-30 ms. Both evoked synaptic potentials and the spike activity in response to click and tone-burst stimulation were analyzed. Depolarizing-hyperpolarizing synaptic potentials were found in response to contralateral and binaural sound stimulation that far outlasted the stimulus (up to 90 ms). When ipsilaterally stimulated, inhibitory responses and no-responses were also recorded. Although few cells were studied, a similar phenomenon was observed using tone-burst stimulation; moreover, a good correlation was obtained between membrane potential shifts and the triggered spikes (input-output relationship). These in vivo results demonstrate the synaptic activity underlying many of the extracellularly recorded discharge patterns. The data are consistent with the known multi-synaptic ascending pathway by which signals arrive at the ICc as well as the descending corticofugal input that may contribute to the generation of long duration post-synaptic potentials.     

Anatomy into the next millennium: quo vadis, or simply where to?

Concerns are raised regarding the status of anatomy as an academic discipline and its future. The traditional place of anatomy in the medical and other curricula is under serious threat. There is a decline in the number of clinically qualified academic staff members in anatomy departments. Options for change if anatomy is to remain among viable academic disciplines are explored.