Continuity and change in social support between young-old and old-old or very-old age

This longitudinal research examined continuity and change in social support in a sample of 74 old-old (74 to 84) or very-old (85 and over) members of the Berkeley Older Generation Study. Considerable continuity in extent of contact was found between 1969 and 1983 for the group as a whole, particularly with respect to family relationships. In beyond-family contacts, declines were observed for men but not women, and for the very-old but not the old-old. Important changes also were observed in involvement or subjective level of commitment: satisfaction with children increased, while involvement beyond the family declined.

Continuity in intellectual functioning: The role of self-reported health

Surviving members of the Berkeley Older Generation Study were interviewed and tested with the Wechsler Adult Intelligence Scale in 1969-1970 and again in 1983-1984, when subjects' ages ranged from 73 to 93. Health was assessed by self-reports at both measurement periods. Although many individuals showed some decline in intellectual functioning, substantial individual differences were apparent at all age levels. More than one half of the subjects showed no reliable change, and a minority showed a reliable increase in verbal scores. The role of self-reported health has increasing importance in the maintenance of intellectual functioning in advanced old age.

Determinants of the first inspiratory volume and functional residual capacity at birth

We have investigated the pattern of pressure and volume changes that occur in vaginally delivered, full-term infants during the onset of spontaneous respiration. Within a few seconds of delivery of the head, simultaneous measurements were made of stomach and esophageal pressure changes together with volume changes determined at the mouth. Values obtained for volume were very similar, but pressure changes were of a greater magnitude than previously reported. A significant correlation has been shown between first inspiratory volume and functional residual capacity (FRC) at the end of the first breath (p less than 0.004). No significant relationship was found between first inspiratory pressure and FRC. However, using a calculated index of inspiratory pressure and time ("inspiratory effort"), a significant relationship of this to FRC was observed (p less than 0.02).

Efficiency of manual resuscitators at birth

The effectiveness of five neonatal/paediatric manual resuscitators was assessed in a group of babies born by caesarean section. Results showed that devices incorporating a large volume reservoir produced the greatest tidal volume, while those with smaller volume reservoirs could not be considered satisfactory for routine use during neonatal resuscitation.

Assessment of HTLV III screening tests in Christchurch

The Christchurch Hospital blood bank has assessed commercial kits designed to test blood donations for the presence of antibody to the retrovirus responsible for acquired immune deficiency syndrome (AIDS). Twenty of 1002 blood donations have been found to be repeatably, positive by one or more of these commercial kits. None was positive by the Western blot technique. Certain patient groups were found to have an elevated number of false positive reactions. Extreme caution is advised when interpreting screening test kit results from donor populations at low risk of AIDS.

Manipulation of ventilator settings to prevent active expiration against positive pressure inflation

Recent publications have suggested that in infants receiving artificial ventilatory support a particular pattern of interaction between spontaneous breaths and ventilator inflations (active expiration against each ventilator inflation) may be important in the production of pneumothoraces. We have looked at patterns of interaction from 47 preterm infants studied on 51 occasions. We found that active expiration against the ventilator occurred on a total of 16 occasions. This pattern was prevented on 14 occasions by altering the ventilator settings. In two other babies, the pattern persisted but neither baby developed a pneumothorax.

Continuous positive airway pressure via a single nasal catheter in preterm infants

We present the results of giving continuous positive airway pressure (CPAP) via a single nasal catheter to 20 preterm infants. A beneficial effect in terms of reduced work of breathing (P less than or equal to 0.01) and improved pattern of respiration (P less than or equal to 0.05) are demonstrated. CPAP via a single nasal catheter does not seem to mediate effects inside the thorax unlike CPAP delivered by a tight fitting face mask. Gross variations in CPAP level may result from altering the infant's position.

Effects of positive end expiratory pressure during ventilation of the preterm infant

Twenty two babies receiving artificial ventilator support were studied on 29 occasions to determine the effects of low levels of positive end expiratory pressure. Mean positive end expiratory pressure during these studies was 2.6 cm H2O. Changes in tidal volume, minute volume, compliance, and transcutaneous gas trends produced by the use of positive end expiratory pressure were investigated. Positive end expiratory pressure consistently caused a rise in transcutaneous oxygen tension. Changes in transcutaneous carbon dioxide tension after the introduction of positive end expiratory pressure were less consistent and not of the same magnitude as the observed reduction in minute ventilation. Compliance values fell with the use of positive end expiratory pressure.

Calculation of mean airway pressure during neonatal intermittent positive pressure ventilation and high frequency positive pressure ventilation

Because mean airway pressure (MAP) is extensively used to quantify ventilation administered during the neonatal period, the accuracy and reproducibility of the techniques currently used to define MAP were assessed. All techniques were found to compare closely with MAP measured by integration of the pressure wave form even at ventilator rates in excess of 100 breaths per minute. It was therefore concluded that all methods currently used are satisfactory for clinical use.

Inspiratory time and tidal volume during intermittent positive pressure ventilation

We measured the tidal volume achieved during intermittent positive pressure ventilation using various inspiratory times with a minimum of 0.2 seconds. Results indicate that tidal volume shows no reduction with inspiratory times down to 0.4 seconds. An inspiratory time of 0.3 seconds, however, is likely to reduce tidal volume by 8%, and at 0.2 seconds a 22% fall may be anticipated.

Formal instruction in United Kingdom medical schools about death and dying

The paper reports the findings of a short questionnaire survey of medical schools conducted in June 1983. All U.K. schools replied. Only four schools do not provide formal instruction about death and dying for all their students.

'We didn't want him to die on his own' ? nurses' accounts of nursing dying patients

This paper is based on nurses' accounts of their experiences of nursing dying patients, and the attitudes towards such work which they expressed. Nurses reported high levels of emotional involvement with their dying patients and expressed a preference for being honest with them about their condition. They preferred to nurse patients who were aware of their death rather than those who were not. Structural aspects of the ward organization which facilitate such action and attitudes are identified.

Use of local electrostatic environments of cysteines to enhance formation of a desired species in a reversible disulfide exchange reaction

The role of electrostatic factors has been evaluated for the reversible disulfide exchange reaction between N-acetylcysteine (A) and a peptide fragment (B) comprising residues 85-114 of Kunitz soybean trypsin inhibitor. In A, the sulfhydryl group has a negative carboxyl neighbor on the cysteine itself. In B, the only charged group within five residues of the single cysteine at position 86 is the positive N-terminal amino group on residue 85. The concentrations of the monomers A and B and of the disulfides AA, AB and BB have been determined as a function of time in kinetic experiments at pH 7, 23 degrees C and ionic strengths of 20 mM and 1 M. At both ionic strengths the sulfhydryl acid dissociation constants Ka have been determined for A and B, as well as the four rate constants for the disulfide exchange reaction. The electrostatic effects are small in magnitude but occur in expected directions. Local cysteine environments enhance formation of the mixed disulfide (AB), having a favorable configuration of adjacent unlike charges and generate decreases in the AA and BB disulfides joining regions of identical charge. These experiments represent an initial step towards use of intrinsic protein functional groups to direct formation of specific disulfides in a synthetic protein.

Surface treatment studies aimed at streamlining fissure sealant application

Three laboratory studies were carried out with the aim of improving or streamlining enamel surface treatment procedures in fissure sealing. In Study 1, the effect of reducing acid etch time from 60 s to 10 s was assessed by SEM and tensile bond strength measurements. Reduction in etch time produced a finer etch pattern, gave a reduced but still high, bond-strength, albeit with slightly poorer long-term adhesion. Study 2 showed that a conventional acid etch treatment could completely remove acquired pellicle, without prior prophylaxis. SEM studies and bond-strength measurements corroborated this view. In Study 3, compressed air and chemical drying agents were compared for drying speed and efficiency. Compressed air gave more rapid, thorough drying, and greater resultant bond strengths.

Coping with stroke at home

Relatives of stroke patients were asked about their knowledge and anxieties about strokes at three points in time: 72 hours after hospital admission, immediately prior to discharge, and 6 months post-discharge. During the period of hospitalization relatives were provided with information and encouraged to participate in patient care with the aim of increasing their skills in coping with the stroke patient at home. The relatives reported to be coping with the practical problems of care, but all reported problems with the emotional aspects of caring for the stroke patient.

Electrostatic influence of local cysteine environments on disulfide exchange kinetics

The ionic strength dependence of the bimolecular rate constant for reaction of the negative disulfide 5,5'-dithiobis (2-nitrobenzoic acid) with cysteines in fragments of naturally occurring proteins was determined by stopped-flow spectroscopy. The Debye-Hückel relationship was applied to determine the effective charge at the cysteine and thereby determine the extent to which nearby neighbors in the primary sequence influence the kinetics. Corrections for the secondary salt effect on cysteine pKs were determined by direct spectrometric pH titration of sulfhydryl groups or by observation of the ionic strength dependence of kinetics of cysteine reaction with the neutral disulfide 2,2'-dithiodipyridine. Quantitative expressions was verified by model studies with N-acetyl-cystein. At ionic strengths equal to or greater than 20 mM, the net charge at the polypeptide cysteine site is the sum of the single negative charge of the thiolate anion and the charges of the amino acids immediately preceding and following the cysteine in the primary sequence. At lower ionic strengths, more distant residues influence kinetics. At pH 7.0, 23 degree C, and an ionic strength of 20 mM, rate constants for reaction of the negative disulfide with a cysteine having two positive neighbors, one positive and one neutral neighbor, or two neutral neighbors are 132000, 3350, and 367 s-1 M-1, respectively. This corresponds to a contribution to the activation energy of 0.65- 1.1 kcal/mol per ion pair involved in collision between the cysteine and disulfide regions. The results permit the estimation that cysteine local environments may provide a means of achieving a 10(6)-fold range in rate constants in disulfide exchange reactions in random-coil proteins. This range may prove useful in developing strategies for directing disulfide pairing in synthetic proteins.

A possible explanation as to why the newly sighted commonly perform well on pseudoisochromatic colour vision tests

Patients whose vision has been restored after long periods of blindness commonly experience difficulty in perceiving. Parodoxically, such patients often perform well on pseudoisochromatic colour-vision tests. A well-known example is Gregory and Wallace's subject, S.B. who performance on the Ishihara test was perfect. It is suggested that restoration of vision may be associated with relatively poor visual acuity and that this, by filtering higher spatial frequencies, enhances the legibility of pseudoisochromatic test patterns. Two experiments confirm that the Ishihara plates are more legible when seen as defocused images.