Decay kinetics of calcium currents in rat sensory neurones: analysis at two internal free calcium concentrations

The patch-clamp technique in whole-cell configuration was, used to investigate the kinetics of decay of calcium currents in rat sensory neurones. Whole-cell recording permitted control of the internal medium, particularly of the internal free calcium concentration, which was maintained at either 10^–9 M or 10^–6 M using a high concentration of Ca buffer. The inactivation decay of the total Ca current elicited above –10 mV was found to be faster at pCa 6 than at pCa 9. The total current contained three exponential components which were tentatively identified as the three types of Ca currents (ICa_T, ICa_N and ICa_S). Kinetic analyses indicated that the control of the inactivation process by internal Ca results from an effect on both high-threshold Ca currents, ICa_N, and ICa_S. The inactivation kinetics reported in the literature presents a large variability depending on the cell type. We propose that this variability may result from differences in the capacity of those cells to control their internal Ca.     

Growth of diploid cells from breast cancers

Cell cultures were derived from normal and cancerous breast tissues and from metastases by methods that selected for relatively adherent epithelial aggregates. Karyotypic analyses of first or second passage cultures yielded predominantly normal diploid cells. Nonclonal aberrations were more common in tumor-derived than in normal cultures. Three of the cultures that originated from metastases were characterized by abnormal clones. These results support observations based on DNA content, which indicate that a considerable fraction of breast cancers are composed predominantly of diploid cells. They differ greatly from chromosomal findings in long-term cultures of tumor effusions and thus emphasize the karyotypic diversity that can be found in tumors from a single tissue of origin--the breast.     

Different ion channel mechanisms between low concentrations of capsaicin and high concentrations of capsaicin and nicotine regarding peptide release from pulmonary afferents

Vagal nerve stimulation (1 Hz for 1 min), capsaicin (10^-8 M and 10^-6 M), resiniferatoxin (3 × 10^-10 M) and nicotine (10^-4 M) evoked a non-cholinergic bronchoconstriction in the isolated perfused guinea-pig lung preparation. Simultaneously there was an increase in the perfusate levels of calcitonin gene-related peptide-like immunoreactivity, suggesting release from sensory nerves. Both the bronchoconstriction and peptide release evoked by a low concentration of capsaicin (10^-8 M) and that evoked by nerve stimulation were depressed by tetrodotoxin, suggesting involvement of Na⁺ channel dependent depolarization. Since the effects of capsaicin (10^-8 M) and vagal nerve stimulation were inhibited by ω-conotoxin but not influenced by nifedipine, the Ca²⁺-channel involved is probably of N-type. Furthermore, the capsaicin analogue resiniferatoxin also evoked ω-conotoxin sensitive peptide release and bronchoconstriction. At the higher capsaicin concentration (10^-6 M), the functional response was only slightly inhibited by wconotoxin or tetrodotoxin indicating that capsaicin at this concentration evoked peptide release and functional effects through other mechanisms, probably involving Ca²⁺ fluxes in the non-selective cation channel associated with the proposed capsaicin receptor. The nicotine (10^-4 M) evoked peptide release and bronchoconstriction were only marginally influenced by ω-conotoxin or tetrodotoxin. It is concluded that the ion-channel mechanisms underlying the peptide releasing properties of antidromic nerve stimulation and low concentrations of capsaicin are similar and depend on action potential propagation, whereas capsaicin in high, toxic concentration and nicotine mainly act via receptor operated channels.     

Subsensitivity of T lymphocytes to sympathomimetic and cholinergic stimulation in bronchial asthma.

The effect of adrenergic and cholinergic drugs on short incubation “active” E rosette formation was studied in 19 patients with bronchial asthma and 17 healthy controls. Both groups had an equal absolute number of baseline “active” E rosettes, but the asthmatics demonstrated a higher percent baseline value. The beta adrenergic drug isoproterenol (10^?3 M) inhibited the formation of “active” E rosettes in asthmatics by only 18.0% as compared to a 60.8% inhibition in the control group. Carbamylcholine (10^?5 M) a cholinergic agonist, also showed a lower than normal response in asthmatics, 34.3% enhancement of “active” E rosetting compared to a 52.4% enhancement in the controls. The alpha adrenergic agent phenylephrine (10^?5 M) exhibited equal enhancing effects in both groups, 34.2% in the asthmatics and 36.5% in the controls. Isoproterenol (10^?3 M) had a minimal effect on inhibition of long incubation “total” E rosettes in both groups studied. The beta adrenergic abnormality conforms to the beta blockade theory of asthma of Szentivanyi. The cholinergic abnormality is unexplained in view of the hyperresponsiveness of patients with asthma to cholinergic agents in vivo. Patients with bronchial asthma probably have an autonomic dysfunction that may play a role in the pathogenesis of their disease.     

Post-Traumatic Survival of Sensory Neurons of Different Subpopulations

Immunohistochemical studies were performed to address the expression of the high-molecular-weight component of the neurofilament triplet NF200 (a marker of neurons forming A fibers) and the binding of isolectin B4 (IB4) by neurons of the L4-5 spinal ganglia after ligation or section of the sciatic nerve in rats. A total of 15% of neurons in the ganglia of intact rats expressed NF200. By 90 days after nerve ligation, the proportion of NF200+ neurons decreased two-fold; administration to these rats of the nerve regeneration stimulator xymedone increased the number of NF200+ neurons by 50.7% compared with controls (ligation, no treatment). In intact rats, 23.6% of neurons bound IB4. The proportion decreased by 2.6% 30 days after nerve ligation and to undetectable levels by 90 days; xymedone increased the proportion of surviving IB(4)+ neurons more than eight-fold. IB(4)+ neurons were more likely to enter post-traumatic apoptosis. Ligation of the nerve was followed by survival of fewer NF200+ and IB(4)+ neurons than section of the nerve, which suggests that axon lengthening is a factor maintaining neuron survival. The pyrimidine derivative xymedone increased the survival of neurons of both subpopulations, especially IB(4)+ neurons.     

Correction of lipid composition of the lymph and blood during immediate type hypersensitivity

The survival of neurons is a key condition for complete posttraumatic regeneration of the peripheral nerve. In experiments on rats we studied survival capacity of different neuronal subpopulations in L_IV-L_V dorsal root ganglia after ligation or transection and suturing of the sciatic nerve. Experiments with nerve ligation showed that IB4⁺ neurons are more sensitive to the injury than NF200⁺ neurons. By day 90 after ligation of the sciatic nerve IB4⁺ neurons were virtually not detected in the dorsal root ganglia. By day 90 after nerve transection the number of surviving NF200⁺ and IB4⁺ neurons decreased by 26.1 and 21.4%, respectively, in comparison with intact animals. Treatment with xymedon, a regeneration stimulator, led to a 48.5% increase in the number of surviving NF200⁺ neurons by day 30 after ligation of the nerve and a 50.7% increase by day 90. The number of surviving IB4⁺ neurons increased more than 8-fold by this term after ligation of the nerve and drug stimulation. Xymedon had a neuroprotective effect towards both neuron subpopulations, more intensely preventing apoptosis of IB4⁺ neurons.     

ACh and 5-HT stimulated thermogenesis at different core temperatures in the He-Cold hypothermic hamster

Hamsters in deep experimentally induced hypothermia, at body temperatures between 7 degrees C and 11.5 degrees C, were microinjected with 5-HT and ACh at brain sites in the anterior-preoptic area of the hypothalamus (AH/POA). ACh or 5-HT was injected into an AH/POA site at different starting core temperatures in different groups of hypothermic hamsters. Colonic temperatures (Tc) were maintained, following He-Cold induction, in a temperature controlled environmental chamber and measured with a YSI thermister probe and YSI telethermometer. Injections of either 5-HT or ACh at Tc's between 7.0 degrees C and 9.0 degrees C elicited only modest increases in Tc i.e., 0.3 degrees C--0.6 degrees C, respectively. As Tc increased, however, to ranges between 9.1 degrees C--10.0 degrees C and in different animals to greater than 10 degrees C both ACh and 5-HT at the same sites elicited significant increases in Tc, 1.5 degrees C for 5-HT and 2.2 degrees C for ACh compared to saline injections. These data suggest that at the lowest Tc's we are observing a "cold block" of temperature sensitive sites in the AH/POA. Increasing the starting Tc beyond 9.0 degrees C however, evokes significant increases in heat-gain following AH/POA injection of either ACh or 5-HT. These data are consistent with Myers' observations concerning the organization of heat-gain mechanisms at AH/POA sites. In addition, they suggest that both the afferent limb of the heat-gain circuit (5-HT) and the efferent limb of the circuit (ACh) are functionally impaired when Tc is close to the physiological limit in the He-Cold hypothermic hamster.     

ER "capture" of the skid-row alcoholic

In response to the spiraling anger and frustration voiced by the emergency room (ER) medical staff and the observed negative interactions between the alcohol-dependent patient and the ER staff, the author completed a 6-month retrospective review of all patients evaluated by the ER service with a complaint of alcohol abuse, chronic alcoholism, or requesting detoxification. As a result of that study, an ER-based comprehensive approach to the management of this population was proposed. Utilizing an existing Connecticut state statute, a specific approach to manage the skid-row alcoholic arriving repeatedly in the ER was developed. I report on this ER-based model and an approach to "capturing" the skid-row alcoholic.     

Electromyography and nerve conduction study in autosomal dominant olivopontocerebellar atrophy

Summary Electromyographic examination and studies of motor and sensory conduction velocities were performed in 11 patients with a presumptive diagnosis of olivopontocerebellar atrophy with autosomal dominant transmission. Peripheral nervous system involvement was shown in eight. In two patients with early onset of disease, electrophysiological alterations clearly pointed to severe axonal degeneration, whereas in six they were compatible with slight demyelination.

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Zusammenfassung Bei elf Patienten, bei welchen eine olivopontocerebelläre Atrophie mit autosomal dominanter Übertragung angenommen wurde, führten wir eine elektromyographische Untersuchung und eine Bestimmung der motorischen und sensiblen Erregungsleitungsgeschwindigkeit durch. Bei acht dieser Patienten wurde eine Mitbeteiligung des peripheren Nervensystems nachgewiesen. In zwei Fällen mit frühem Krankheitsbeginn wiesen die elektrophysiologischen Veränderungen eindeutig auf eine schwere axonale Degeneration hin, während bei sechs die Befunde mit einer leichten Demyelinisation vereinbar waren.