Ocular perfusion pressure and choroidal thickness in eyes with polypoidal choroidal vasculopathy, wet-age-related macular degeneration, and normals.

PURPOSE: To measure the choroidal thickness and ocular perfusion pressure in eyes with polypoidal choroidal vasculopathy (PCV), wet-age-related macular degeneration (AMD), and age-matched normal subjects, and look for a possible association between the two. METHODS: This was a prospective study including 22 eyes with PCV, 33 eyes with wet-AMD, and 35 age-matched normal eyes. Choroidal thickness was measured using enhanced depth imaging (EDI) with spectral-domain optical coherence tomography (SD OCT). Mean ocular perfusion pressure (MOPP) was calculated using the mathematical formula 2/3[DBP+1/3{SBP × DBP}]-IOP (DBP-diastolic blood pressure, SBP-systolic blood pressure, IOP-intraocular pressure). Analyses were carried out using SPSS 14 software and comparisons of mean made using't' tests. RESULTS: Eyes with PCV showed increased (285.9 µm; subfoveal) choroidal thickness, whereas eyes with wet-AMD (119.4 µm; subfoveal) showed reduced choroidal thickness in comparison with normal eyes (186.77 µm; subfoveal). MOPP in the PCV group was 57.85 mm Hg (P value 0.00), in the wet-AMD group was 52.1 mm Hg (P-value 0.12), and in the normal group was 49.79 mm Hg. CONCLUSION: It is postulated that higher MOPP in eyes with PCV could have an etiologic implication in disease manifestation and progression. Larger studies with longer follow-up may help validate these findings.

Free volume study on calcification process in an intraocular lens after cataract surgery.

An opacified intraocular lens explanted from a patient in the postoperative period after phacoemulsification was investigated to find the cause of opacification. From the UV-visible and energy dispersive X-ray spectroscopy (EDS) measurements, the opacification in the present case seems to be due to calcification of the intraocular lens and not due to modification in the UV absorber material of the lens. The average free volume size of the intraocular lens both in unimplanted and explanted state were obtained from positron lifetime spectroscopy (PLS). Further, the combined FTIR and PLS results indicate that calcium gets into the free volume cavities of the intraocular lens matrix as a cationic moiety, may be in the form of Ca(++). The small decrease in glass transition temperature of the calcified lens seems to indicate the plasticizing action of calcium ions. The present results could be of some use in the design of the intraocular lens material in which calcification would be minimum.

Permanent pacemaker implantation via the femoral vein: an alternative in cases with contraindications to the pectoral approach.

BACKGROUND: This paper presents a consecutive series of permanent pacemakers (PPM) implanted via the femoral vein in patients with contraindications to pacing systems via the superior vena cava (SCV). The femoral vein approach is a less invasive and feasible alternative to epicardial lead placement. METHODS: Twenty-seven patients had femoral pacemakers inserted. Indications for femoral vein pacemaker insertion were: SVC/subclavian obstruction (12 patients, 44.4%), previous infection in SVC leads (four patients, 14.8%), mastectomy and/or radiotherapy to chest (four patients, 14.8%), multiple leads in SVC (two patients, 7.4%), recurrent erosion (two patients, 7.4%), abnormal anatomy (one patient, 3.7%), painful pacemaker pocket (one patient, 3.7%) and burns (one patient, 3.7%). Fifty-one leads, 25 atrial and 26 ventricular, were inserted. The majority of leads were active fixations (96% of atrial leads and 85% ventricular leads). RESULTS: During a mean follow-up of 36.5 months (range 0.9-116.5), six additional unplanned procedures were performed in four patients. Atrial lead displacement occurred in five leads (20%). There were no ventricular lead displacements. In two patients, box revision for pre-erosion was required. One patient had persistent pain at the site of abdominal pacemaker generator. Infection, thromboembolic events, thromophlebitis, evidence of lower limb venous occlusion and lead fracture did not occur. CONCLUSION: Femoral vein PPM are a simple and feasible alternative in patients in whom the SVC approach is contraindicated.

What is the signal for the posttranslational arginylation of proteins?

The N-terminal, posttranslational arginylation of proteins is ubiquitous in eukaryotic cells. Previous experiments, using purified components of the reaction incubated in the presence of exogenous substrates, have shown that only those proteins containing acidic residues at their N-terminals are arginylation substrates. However, data from experiments that used crude extracts of brain and nerve as the source of the arginylating molecules, suggest that the in vivo targets for arginylation are more complex than those demonstrated using purified components. One of the proposed functions for arginylation is as a signal for protein degradation and proteins that have undergone oxidative damage have been shown to be rapidly degraded. In the present experiments we have tested the hypothesis that the presence of an oxidatively damaged residue in a protein is a signal for its arginylation. These experiments have been performed by adding synthetic oxidized peptides to crude extracts of rat brain, incubating them with [3H]Arg and ATP and assaying for arginylated peptides using RP-HPLC. Results showed that while the oxidized A-chain of insulin was arginylated in this system, confirming previous experiments, other peptides containing oxidized residues were not. When a peptide containing Glu in the N-terminus was incubated under the same conditions it too was not a substrate for arginylation. These findings show that neither the presence of an N-terminal acidic residue nor an oxidized residue alone are sufficient to signal arginylation. Thus, another feature of the oxidized A-chain of insulin is required for arginylation. That feature remains to be identified.

Determining the optimal pacing intervention rate for vasovagal syncope.

INTRODUCTION: In this study, patients with rate hysteresis pacemakers implanted for vasovagal syncope were re-studied using serial tilt testing to determine whether, once triggered, pacing was more effective if the intervention rate was higher than the standard rate. METHODS AND RESULTS: Twenty patients (mean age 55.4 years, range 23-81, 14 male) were studied, with randomisation to either initial standard rate (80-90 beats/min) intervention, or to initial high rate (120 beats/min) intervention. Although 18 of the 20 reported complete abolition of syncope since pacing, only 8 patients could be objectively assessed. The respective mean time to tilt down after symptom onset with standard and high rate intervention was 193+/-234s and 185+/-143s, (P>0.05). CONCLUSION: Repeat tilt testing was only of limited value in assessing the benefit of pacing. There was no advantage with high rate intervention in delaying the loss of consciousness (or intolerable symptoms) after the initial onset of symptoms.

Cardioinhibition during tilt testing identifies patients who may benefit from pacing.

UNLABELLED: This study examined whether the various hemodynamic collapse patterns observed during tilt testing in patients with suspected neurocardiogenic syncope are relevant when planning therapy, particularly whether a predominantly cardioinhibitory response predicts a beneficial response from pacing. METHODS: The effects of temporary atrioventricular (A-V) sequential pacing were studied during tilt testing in 34 patients 48.2 +/- 18.5 years of age. The patient population was divided into a cardioinhibitory group (VASIS classes 2A and 2B) or mixed group (VASIS classes 1 and 3) according to their response to baseline tilt testing. The test was then repeated during A-V pacing with rate hysteresis. A positive response to A-V pacing was defined as a > or = 30-second increase between onset of symptoms and syncope, or mitigation of symptoms compared with the baseline tilt test. RESULTS: The study protocol was not successfully completed in three patients. Among the remaining 31 patients, a baseline cardioinhibitory response was observed in 17, and a mixed response in 14 patients. A-V sequential pacing was successful in 13 of 17 patients with a cardioinhibitory response versus 5 of 14 patients with a mixed response (P = 0.024). CONCLUSION: The presence of a predominantly cardioinhibitory collapse pattern (VASIS 2A and 2B) during baseline tilt testing doubled the likelihood of successful temporary A-V sequential pacing, and may identify patients with neurocardiogenic syncope most likely to benefit from permanent dual chamber pacing.

Breastfeeding in babies delivered by cesarean section.

One hundred mothers undergoing cesarean section and their infants were studied regarding various factors affecting the establishment of breastfeeding during their stay in hospital (mean = 11 +/- 3.6 days). Nearly two-thirds (65.7%) of mothers who underwent elective cesarean section, and 62.8% of mothers who received spinal anesthesia were breastfeeding exclusively; while only 53.8% mothers who had undergone an emergency cesarean section and 28.6% who received general anesthesia were exclusively breastfeeding their neonates. All 9 mothers who initiated breastfeeding within 12 h of the surgery were practicing total breastfeeding. In contrast only 5.8% of mothers who initiated breastfeeding after 96 hours, were exclusively breastfeeding their neonates. Total breastfeeding was more frequent (86.8%) in newborn infants who received prelacteal feeds by spoon as compared to those who received by feeding bottle (33.3%). Babies separated from the mothers in hospital were less likely (35.5%) to be on total breastfeeding as compared to those (68.1%) who were not separated from their mothers. This study suggests that for proper establishment of breastfeeding in mothers undergoing cesarean section an elective procedure under spinal anesthesia promotes, early initiation of breastfeeding. Early initiation of breastfeeding has highly significant correlation with establishment of breastfeeding while separation of babies from mothers discourages breastfeeding.

Breastfeeding and childhood cancer.

Total duration of breastfeeding and of exclusive breastfeeding was studied and compared in 99 childhood cancer cases and 90 controls. The difference between the average duration of breastfeeding in cases and controls was significant (p < 0.05), but when average duration of exclusive breastfeeding was compared in cases and controls the difference was highly significant (p < 0.001). In lymphoma cases and controls the difference between the average duration of breastfeeding was moderately significant (p < 0.01). However, when average duration of exclusive breastfeeding was compared in lymphoma cases and controls the difference was highly significant (p < 0.001). When other cancer groups and controls were compared with respect to their total duration of breastfeeding and duration of exclusive breastfeeding the differences when insignificant (p > 0.05). Cases and controls were not different with respect to their age, sex, birth year, birth order, age and educational status of mothers, smoking of fathers and socioeconomic status. However, a positive family history of cancer was obtained in 4 (4%) of cases whereas in controls it was obtained in only 1 (1.1%).

PIP: Between April 1991 and June 1992 in India, physicians compared data on 99 childhood cancer cases with data on 90 sex, age, and hospital matched controls to examine the relationship between duration of total breast feeding and exclusive breast feeding and childhood cancer. Most of the children were patients at G.S.V.M. Medical College in Kanpur or at K.G. Medical College in Lucknow. Cases and controls were essentially the same in respect to birth order, age and educational status of mothers, smoking of fathers, and socioeconomic status. 65.7% of cases had leukemia. The duration of total breast feeding was significantly longer for controls than cases (10 months vs. 8 months; p .05). The difference between mean duration of exclusive breast feeding between mean duration of exclusive breast feeding between cases and controls was significant (4.6 months vs. 3.2 months; p .001). Controls were more likely to have undergone a longer duration of total breast feeding and exclusive breast feeding than were lymphoma cases (10 months vs. 6.15 months; p .01 and 4.6 months vs. 3 months; p .001, respectively). 58% of lymphoma cases had non-Hodgkins lymphoma. When the researchers compared other cancer groups and controls, no significant difference between the 2 groups existed in respect to total breast feeding and exclusive breast feeding. These results suggest that breast feeding has a protective effect against childhood cancer. Further, they indicate that exclusive breast feeding provides more beneficial immunological effects than breast feeding supplemented by artificial feeding. The high rate of breast feeding in India may explain the low incidence of childhood cancer in India (e.g., around 6/100,000 vs. 18/100,000 in Israel).