Inward rectification in response to FMRFamide in Aplysia neuron L2: summation with transient K current

The response of Aplysia abdominal ganglion neuron L2 to the molluscan neuroactive peptide Phe-Met-Arg-Phe-NH2 (FMRFamide) was studied in voltage-clamp experiments. In all of the experiments, focal application of the peptide to the soma activated an inward rectifier current and reduced the apparent amplitude of the transient K current, IA. In a few cells, Na and K currents were activated in addition to these effects. Voltage-jump experiments were performed to study the ionic dependence, kinetics, and voltage dependence of the inward rectifier. Inward rectification increased exponentially during hyperpolarizing pulses and recovered exponentially on return to the resting potential. The reversal potential was variable, but was near -40 mV at the beginning of experiments. Inward rectification was insensitive to changes in external Na, Ca, or K concentration, but lowering the external Cl concentration had complicated effects on current amplitude. When KCl microelectrodes were used, perfusion with low-Cl external saline increased the amplitude of the peptide-dependent inward rectifier and shifted its reversal potential to a more positive voltage. With KAc microelectrodes, perfusion with low-Cl saline reduced the amplitude of the current. Inward rectification increased when a KAc microelectrode was withdrawn and replaced with a low-resistance KCl electrode, even when there was no measurable change in reversal potential. These results suggest that the FMRFamide-dependent inward rectifier is a Cl current that, like the current described by Chesnoy-Marchais (1982, 1983), is modulated by intracellular Cl. FMRFamide reduced the apparent amplitude of IA without affecting the voltage dependence of IA activation or inactivation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Dorsal sympathectomy for hyperhidrosis--the posterior paravertebral approach

Definitive therapy for hyperhidrosis is sympathectomy. The authors have used a posterior approach to perform 36 dorsal sympathectomies for upper extremity hyperhidrosis in 18 patients (12 female, 6 male). All 18 patients suffered from excessive sweating of the upper extremity (17 palmar, 1 axillary) that caused significant psychological and occupational problems. Eleven patients (61.1%) had lower extremity involvement as well. For all 18 patients conservative medical treatment had failed. Bilateral operations were performed, via a posterior extrapleural approach, through the bed of the third rib. All 36 limbs were relieved of excess sweating. There were no deaths and only two minor wound complications. In no patient did Horner's syndrome develop. Long-term follow-up did not reveal any recurrence of hyperhidrosis. Two patients did complain of compensatory hyperhidrosis of the lower extremities. Dorsal sympathectomy was effective in all of the patients with upper extremity hyperhidrosis in this series. The posterior approach is technically simple, allows simultaneous bilateral operations, and is associated with only infrequent minor complications.     

Children With Chronic Physical Disorders: Maternal Reports of Their Psychological Adjustment

Advances in biomedical science have resulted in dramatic improvementsin the medical care of chronically ill and handicapped children.Past measurement problems have resulted in a lack of clarityregarding the psychological adjustment of these children. Themothers of 270 chronically ill and handicapped children wereadministered the Child Behavior Checklist in an attempt to identifypatterns of behavioral functioning across six pediatric chronicdisorders: juvenile diabetes, spina bifida, hemophilia, chronicobesity, juvenile rheumatoid arthritis, and cerebral palsy.In general, it was found that children in all chronic disordergroups were perceived by their mothers as evidencing on theaverage more behavioral and social competence problems thanexpected based on norms for children in general. However, theirbehavioral and social adjustment was reported as better thanthat of a normative sample of children referred to mental healthclinics. There were essentially no differences between childrenwith different chronic disorders in terms of behavior problemsand social competence. The results were taken to support theview that these children were as a group at risk for adjustmentproblems. They were also discussed in terms of the noncategorialapproach, which suggests that similar psychosocial challengesare faced across pediatric chronic physical disorders.     

Altered patterns of reflex excitability subsequent to contusion injury of the rat spinal cord.

1. The present study investigated regulation of reflex excitability after experimental contusion injury of the spinal cord. 2. Four measures of H-reflex excitability were evaluated in normal rats and at 6, 28, and 60 days after contusion injury at the T8 level: 1) reflex thresholds, 2) slope of the reflex recruitment curves, 3) maximal plantar H-reflex/maximal plantar M-response (Hmax/Mmax) ratios, and 4) rate-sensitive depression (i.e., the decrease in reflex magnitude relative to repetition rate). 3. Tested as a function of the afferent volley magnitude, the thresholds for reflex initiation fell progressively subsequent to contusion injury. No change was observed at 6 days postinjury, and the decrease at 28 days was not significant. However, by 60 days postinjury, the threshold had decreased by 23% of the maximal afferent volley, and this decrease was significant, [analysis of variance (ANOVA, P < or = 0.01)]. 4. Hmax/Mmax ratios elicited in postcontusion animals at 0.3 Hz were not significantly different from those recorded in normal animals. 5. The slopes of the recruitment curves were markedly reduced subsequent to contusion injury. The decrease was greatest at 6 days postinjury. Although some recovery toward normal occurred at 28 and 60 days postinjury, the slopes of recruitment curves in postcontusion animals remained significantly decreased. 6. H-reflexes elicited at 1-5 Hz were less sensitive to rate depression in postcontusion animals than in normal animals at the same respective frequencies. The decrease was progressive in onset, becoming significant by 28 days postinjury, and of an enduring nature, i.e., still significantly different from normal in the reflexes tested 60 days postinjury. 7. Rate sensitivity of the tibial nerve monosynaptic reflex (MSR) was also compared in normal and postcontusion animals. Rate sensitivity of the tibial MSRs was significantly reduced at 28 and 60 days post-contusion, compared with normal animals. 8. These data indicate that significant changes in lumbar reflex excitability result from midthoracic contusion injury of the spinal cord. These changes include reflex threshold, slope of recruitment, and rate-sensitive depression. Although recruitment slope was most altered in the shortest postinjury interval tested, followed by some recovery, the other changes were progressive in onset and enduring in duration.     

Presentation of abdominal tuberculosis to general surgeons.

Abdominal tuberculosis (TB) continues to give rise to diagnostic and therapeutic challenges. A total of 24 patients with abdominal TB who presented to general surgeons over a 9-year period have been reviewed. Most (92 per cent) of these patients were Asian; only one had a past history of pulmonary TB. The most common presenting complaint was abdominal pain in 21 patients (88 per cent) with the associated symptoms of weight loss in 18 (75 per cent), anorexia in 15 (62 per cent) and night sweats in 13 (54 per cent). A tissue diagnosis was obtained in 18 patients (75 per cent) and 17 patients (71 per cent) underwent laparotomy. These results show that the diagnosis of abdominal TB is still difficult to establish, and that many patients undergo laparotomy despite the existence of less invasive diagnostic procedures.