Seizure activity and cortical spreading depression monitored by an extrinsic potential-sensitive molecular probe

Using surface fluorescence and reflectance measurements from the exposed cerebral cortex, several potential-sensitive molecular probes, primarily oxonol V, have been evaluated as indicators of electrical activity changes developing during seizure activity in the mongolian gerbil. Intraventricular injection of bicuculline, picrotoxin, or KCl produced characteristic cyclic molecular probe fluorescence intensity decreases that could be abolished by the uncoupler CCCP or the mitochondrial electron transport inhibitor rotenone. Smaller fluorophore signals were observed when KCl was applied topically to the exposed cortex. In some cases, as the animals were recovering from anoxia induced by nitrogen inhalation, oscillations similar to those due to spreading depression were observed in both the oxonol V and pyridine nucleotide signals. In all experiments, the molecular probe signals closely followed those of the intrinsic pyridine nucleotides. The drug-induced oxonol V signal alterations have been provisionally interpreted as due at least in part to the reduction of the mitochondrial membrane potential that accompanies a state 4 to state 3 transition. Measurements at the oxonol V fluorescence excitation wavelength indicated that only small changes in the reflectance signal occurred during seizure activity suggesting minimal blood volume change contributions to the extrinsic probe signal.

Colloidal silica coatings for KrF and Nd:glass laser applications

In this paper we discuss the performance of colloidal silica antireflection coatings which have been developed for use in high-power KrF and Nd:glass lasers. These coatings have reproducibly given transmissions of more than 99.8% per surface and have exhibited laser damage thresholds as high as 20 J/cm(2)for l-ns pulses at 1.06,microm and 8 J/cm(2)for 10-ns pulses at 0.25,microm. These damage thresholds are a factor of between 2 and 3 better than values obtained with evaporated oxide AR coatings. Novel multilayer coatings incorporating colloidalsilica as the low-index layer are also described. One such coating gave more than 50% reflectivity for a two-layer coating at normal incidence.

The impact of passive smoking on emergency room visits of urban children with asthma

Baseline data obtained from a study of 276 children with asthma from 259 low income families were analyzed to test the hypothesis that passive smoking is associated with frequency of emergency room (ER) visits, hospitalizations, and impaired pulmonary function. The data were analyzed using multiple regression techniques. We controlled for other variables that might affect the frequency of ER visits, including smoking by the children themselves and the presence of other irritants or allergens in the child's home. Passive smoking was positively associated with ER visits (p less than 0.01), but not with hospitalizations or abnormalities in pulmonary function. The frequency of days with symptoms of asthma per month was also directly associated with ER visits (p less than 0.02). The estimated mean annual increase in ER visits attributable to the presence of one or more smokers in the household was 1.34 +/- 0.50, an increase of 63% over nonsmoking households. The estimated annual health care cost for emergency care of children with asthma that can be attributed to passive smoking is 92 dollars (95% confidence interval from 24 to 160 dollars) for families with 1 or more smokers.

Nerve fiber growth in culture on tissue substrata from central and peripheral nervous systems

In adult mammals, injured neurons regenerate extensively within the PNS but poorly, if at all, within the CNS. We have studied the effect of substrata consisting of tissue sections from various nervous systems on nerve fiber growth in culture and correlated our results with the growth potential of these tissues in vivo. Ganglionic explants from embryonic chicks (9-12 d) fail to extend nerve fibers onto sections of adult rat optic nerve or spinal cord (CNS) but do so on sciatic nerve (PNS). Dissociated DRG neurons behave similarly whether in serum-containing or defined medium. Tissue substrata from nervous systems that support regeneration in vivo--i.e., goldfish optic nerve, embryonic rat spinal cord, degenerating sciatic nerve--also support fiber growth in culture. Within the same culture, neurons will grow onto sciatic nerve rather than neighboring optic nerve sections, suggesting that the responsible agent(s) is not soluble. In addition, neurons adhere more extensively to sciatic nerve substrata than to optic nerve. The occurrence of 3 molecules known to be involved in neuron-substratum adhesion and nerve fiber growth in vitro has been documented immunocytochemically in the tissue sections. One of these, laminin, is demonstrable in all tissues tested that supported nerve fiber growth. Immunoreactivities for fibronectin and heparan sulfate proteoglycan are found in only some of these tissues. None of these 3 molecules can be demonstrated in neural cells of normal adult rat CNS tissue. Our data suggest that these molecules may be important effectors of nerve regeneration in neural tissues.

The interaction of potential-sensitive molecular probes with dimyristoylphosphatidylcholine vesicles investigated by 31P-NMR and electron microscopy

The effect of a number of commonly employed potential-sensitive molecular probes on the 31P-NMR properties of dimyristoylphosphatidylcholine vesicles at two field strengths has been investigated in order to obtain information on the location and effect of these probes on the membrane bilayer. In comparison to the control dye-free vesicle spectrum, the probes diS-C3-(5) and diS-C4-(5), when added to a vesicle suspension, cause a substantial broadening of the 31P resonance with no detectable chemical shift within an uncertainty of +/- 0.05 ppm at 24 MHz. The spin-lattice and spin-spin relaxation times are also reduced when the cyanines are present by well over 20% relative to those of the control vesicle preparation. The addition of anionic probes, including several oxonol derivatives and merocyanine 540, causes no chemical shift, line broadening, or changes in the relaxation times. Possible explanations for the failure of the anionic probes to alter the vesicle 31P-NMR properties include charge repulsion between these dyes and the phosphate group that prevents the probes from penetrating the bilayer to a depth sufficient to alter the local motion of the phosphate moiety. The 31P resonance broadening and reduction in the relaxation times caused by the two cyanines is at least in part due to an increase in vesicle size as judged by electron microscopy measurements, although an inhibition of the local phosphate motion as well cannot be completely eliminated. The cyanine-mediated increase in vesicle size appears to be due to an irreversible vesicle-fusion process possibly initiated by the screening of surface charge by these probes. The implications of these observations in relation to functional energy-transducing preparations is discussed.

Haemoglobinopathy screening in a 'low-risk' area of the United Kingdom: South Glamorgan, Wales

Figures collected over 2 1/2 years of screening of women attending the antenatal clinics of South Glamorgan, Wales, showed that the percentage of women identified as a risk for haemoglobinopathy trait (7.4%) was almost twice that estimated from the 1981 Census data (4.1%) and that the incidence of a thalassaemia trait in these women (0.38% beta; 0.68% alpha) was similar to that of an area of supposedly greater risk in London (0.46% beta; 0.42% alpha). Figures from one laboratory showed that without a scrutiny of all antenatal clinic blood counts for thalassaemic indices some thalassaemia traits will be missed. The apparent incidence of the HbS trait was 0.13%, and reasons for this being an underestimate are given.

The impact of health education on frequency and cost of health care use by low income children with asthma

A sample of 310 low income urban children with asthma from 290 families was randomized into a control group and an experimental group that received health education to improve asthma management at home. No significant decreases in subsequent health care use were observed when the experimental group was compared to the control group without regard to previous hospitalization. When the comparison was restricted to children who had been hospitalized during the preceding year, however, the experimental group was found to have decreased its use of the emergency room significantly more than the control group (p less than 0.05) and to have experienced a significantly greater reduction in the mean number of hospitalizations (p less than 0.05) during the year of follow-up. The program reduced health care costs for children with one or more hospitalizations, saving $11.22 for every $1.00 spent to deliver health education.

In vivo chemosensitivity testing in patients with gynecologic malignancies and nude mouse xenografts by monitoring cell kinetic parameters and DNA distribution patterns: a preliminary report

Using flow cytometry (FCM) and autoradiography we have evaluated changes in DNA-ploidy patterns as well as cell-cycle perturbations after chemotherapy in 12 patients with accessible tumors and 22 nude mice xenografts. Gynecologic malignancies growing as nude mouse xenografts serve as an experimental model to study the effect of chemotherapy at the cellular level. Excellent correlation was found between fine needle aspiration (FNA) and biopsy material for either FCM or autoradiography. It now appears possible to study the effects of chemotherapy in the patient as well as the animal model using serial FNAs as a microsampling technique.

Managing better: children, parents, and asthma

To evaluate a health education program to improve family management of asthma, 310 children with asthma and their 290 parents were randomly assigned to a program or control group. Program families participated in health education designed to resolve specific management problems and build self-confidence in the ability to manage asthma. Following education, program parents scored better on an asthma self-management index than parents in the control group (+1.57 versus -0.83, P less than 0.0001). Program parents also scored better on two subindices of the self-management index: attack management (+0.87 vs. +0.42, P less than 0.05) and preventive measures (+0.42 vs. -0.35, P less than 0.05). Also, program parents reported significantly more use of guidelines to determine appropriate levels of physical activity for children. Following education, program children reported more use of three management steps than control children: productive cough or postural drainage (59% vs. 35%, P less than 0.004), breathing and relaxation exercises (80% vs. 65%, P less than 0.05), and attempts to stay calm (12% vs. 2%, P less than 0.05). Program children reported significantly less worry than control children about the limitations asthma imposes and about making mistakes at school.

Cauda equina syndrome and lumbar disc herniation

In a retrospective chart review of the cases of thirty-one patients with cauda equina syndrome secondary to a central disc lesion, we identified two modes of presentation. The first was an acute mode (ten patients) in which there were abrupt, more severe symptoms and signs and a slightly poorer prognosis after decompression, especially for the return of bladder function. The second mode of presentation (twenty-one patients) was a slower onset, characterized by prior symptoms for varying time-intervals before the more gradual onset of the cauda equina syndrome. All patients had urinary retention preoperatively. Bladder function was the most seriously affected function preoperatively and remained so postoperatively. The prognosis for return of motor function was good, since twenty-seven of the thirty patients who were operated on regained normal motor function. Preoperatively all patients had sciatica, which was bilateral in fourteen and unilateral in seventeen. The average time to surgical decompression after the patient was seen ranged from 1.1 days for the more acute lesions to 3.3 days for the second group. There was no correlation of these times with return of function. Therefore, even though early surgery is recommended, decompression does not have to be performed in less than six hours if recovery is to occur, as has been suggested in the past.

Low-dose fentanyl: haemodynamic response during induction and intubation in geriatric patients

Twenty-eight surgical patients aged 65-84 were randomly assigned to either a control group (12) induced with thiopentone alone, or a treatment group (16), induced with 3 micrograms . kg-1 fentanyl followed by thiopentone, to determine whether the use of fentanyl during induction would attenuate the cardiovascular response to laryngoscopy and intubation. Patients in the fentanyl group required 47 per cent less thiopentone for induction. Increases in systolic (SBP) and diastolic (DBP) blood pressure were significantly smaller in the group receiving fentanyl at one minute post intubation. SBP rose by 56 mmHg in the control group, compared to 15 mmHg in the fentanyl group; DBP increased 42 mmHg compared to 20 mmHg, respectively. Increases in rate-pressure product were twice as great in the control group compared to the fentanyl group (72.2 vs 36.0 per cent, respectively). Thus, fentanyl, as an adjunct to barbiturate induction, effectively lowered the thiopentone requirement and attenuated the pressor response to laryngoscopy and intubation.

Stercoral perforation of the colon. Concepts of operative management

Stercoral perforation of the colon is a direct result of ischemic pressure necrosis by a stercoraceous mass. In over 90 per cent of cases, the perforation will involve either the sigmoid or rectosigmoid colon and is consistently centrally located within a region of mucosal ulceration of varying diameter and magnitude. A review of 33 surgically treated cases from the literature along with four cases presented here, support resection, end colostomy, and either mucous fistula or Hartmann's procedure as the operation of choice with the lowest operative mortality (23%) when compared to those patients treated by either loop colostomy or exteriorization (71%) or proximal colostomy with plication of the perforation (44%). Irrigation of the distal rectal segment as that for penetrating rectal injury is also recommended.

A case-control study of BCG and childhood tuberculosis in Cali, Colombia

We conducted a case-control study to evaluate the effectiveness of BCG vaccination in preventing childhood tuberculosis (TB) in Cali, Colombia. We ascertained 178 cases aged 0 to 14 years from the respiratory clinics with cough or fever for at least three weeks and a positive chest X-ray for TB, as well as 320 controls who were from the same households but had no symptoms and negative X-rays. Using matched set multiple logistic regression analysis, we found the age- and sex-adjusted relative risk (RR) of TB among vaccinees compared with non-vaccinees to be 0.84 with 95% confidence limits (CL) from 0.43 to 1.62. There was, however, a significantly lowered relative risk of TB with increasing time since vaccination (RR = 0.83 per year since time of vaccination with 95% CL from 0.74 to 0.94.)

Reconstruction of the ala of the nose using a composite free flap from the pinna

A new method of reconstruction of the nasal ala is described using a composite free flap taken from the anterior part of the pinna, based upon the superficial temporal vessels. Forty cadaver dissections have been performed to assess variations in vascular anatomy and a direct branch of the superficial temporal artery was found in 90% of subjects. The flap has been used successfully in two cases.

Epidural morphine prophylaxis of postoperative pain: report of a double-blind multicentre study

In a double-blind placebo-controlled trial, 154 subjects, having intraperitoneal surgery or Caesarean section, and 53 patients undergoing lower limb orthopaedic surgery, received epidural morphine, 5 mg in 10 ml 0.9 per cent NaCl, or placebo, 10 ml 0.9 per cent NaCl, intraoperatively to determine duration of action and efficacy in preventing postoperative pain. Epidural morphine gave significantly longer postoperative analgesia (greater than 11 h) than placebo (3-6 h) in both groups (p less than 0.05) and patients who received morphine required less postoperative analgesic. Obstetric subjects experienced longer pain relief (18.3 +/- 1.3 h) than patients undergoing non-obstetric intraperitoneal surgery (9.2 +/- 1.2 h) (p less than 0.001). Generally mild pruritus affected more than 40 per cent of those receiving morphine, but over 90 per cent of obstetric patients receiving morphine. Respiratory depression occurred in 2-7 per cent of subjects who received morphine; unpredictable in onset, it responded rapidly to naloxone. Epidural bupivacaine, if employed for the surgical procedure, appeared to prolong epidural morphine analgesia. We consider epidural morphine useful in preventing postoperative pain, but its use demands close observation of respiratory rate in a high density nursing area.

A detailed examination of the in vivo and in vitro effects of ACTH on gonadotropin secretion in the adult rat

These studies were designed to: (1) determine the effects of continuous infusion of synthetic ACTH(1-24) on postcastration changes in serum and pituitary LH, FSH and prolactin in the male rat; (2) assess the effects of adrenalectomy on the gonadotropin and prolactin response to ACTH, and (3) test the hypothesis that ACTH may directly (not via adrenal factors) alter gonadotropin secretion at the brain and/or pituitary level. Adult male rats were either orchidectomized (ORX) or orchidectomized-adrenalectomized (ORX-ADX), and were treated continuously for 6 days with ACTH(1-24) (10 micrograms/day) or saline using an osmotic minipump. Animals were killed on day 6 following castration. ACTH treatment reduced serum LH and prolactin levels in ORX rats to mean values +/- SE of 204 +/- 25 and 37 +/- 3 ng/ml respectively, compared to 366 +/- 72 and 62 +/- 7 ng/ml in saline-treated ORX animals. Serum FSH concentrations were not altered by ACTH administration. Pituitary concentrations of LH and FSH, but not prolactin were enhanced by ACTH treatment. Adrenalectomy had no effect on serum and pituitary gonadotropin and prolactin levels, but abolished the effects of ACTH on these parameters. Central (intracerebroventricular) infusion of ACTH(1-24) (6 micrograms/day X 4 days) failed to alter the rise in serum LH in male rats following orchidectomy. Acute treatment with large doses of ACTH of perifused anterior pituitary glands from male rats and chronic treatment with ACTH of enzymatically dispersed anterior pituitary cells from female rats did not influence basal or GnRH-stimulated LH secretion.(ABSTRACT TRUNCATED AT 250 WORDS)