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C B Wolff

Publications and source records attributed to C B Wolff.

31 records · Page 2Linked to original sources
PubMed1978

Sensitivity of the carotid body to within-breath changes in arterial PCO2.

Respiration, sinus nerve chemoreceptor discharge, and carotid arterial pH were monitored in cats. Chemoreceptor discharge frequency showed oscillations that had a respiratory period when averaged over many respiratory cycles. These oscillations disappeared when pH oscillations of respiratory period were eliminated from the carotid arterial blood. The maximum sinus nerve discharge was associated with the most acid point of the recorded pH oscillation. Briefly increasing PCO2 by giving CO2-rich saline into the aortic root resulted in brief reduction in carotid arterial pH, and when this reduction occurred during inspiration tidal volume increased, even with a pH change no larger than the pH oscillations. However, increased chemoreceptor discharge could only be demonstrated when each pH change had twice the amplitude of the pH oscillations. Injections of fixed acid mixed with free carbonic anhydrase transiently increased chemoreceptor frequency, whereas injections of fixed acid alone had no effect. The carotid body is therefore sensitive to small rapid changes in arterial PCO2, and the pH electrode record indicates the size of the stimulus except when fixed acid changes are produced too closely upstream.

Animals↗
PubMed1977

The effects on breathing of alternate breaths of air and a carbon dioxide rich gas mixture in anaesthetized cats.

1. An in vivo pH electrode was used to assess the effect in anaesthetized cats of the administration of 5% CO(2) (21% O(2), balance N(2)) and air as alternate inspirates upon the time course of the carotid arterial pH, and by inference, the P(CO2).2. This method of administration of CO(2) and air resulted in a lowering of the recorded pH with the production of oscillations of twice the duration seen on air alone. These larger oscillations had a period of two respiratory cycles and their amplitude was approximately twice that of normal oscillations.3. The respiratory response consisted in all cases of an increase in mean tidal volume and ventilation, and in 50-60% of recorded runs, of a highly specific sequence of tidal volume changes. The specific sequence was composed of alternately larger and smaller breaths which persisted while the larger oscillations continued.4. The use of the in vivo pH electrode made it possible to determine whether or not the tidal volume alternation was a result of sensitivity to carotid arterial P(CO2) oscillations. By diverting the carotid arterial blood through a mixing chamber the amplitude of the double (respiratory) period oscillations was, in some cases, reduced but not eliminated. In these cases the specific pattern of tidal volume changes was still present in 60% of trials. In the cases where the pH fluctuations were completely eliminated the specific respiratory pattern was never present.5. Average breath to breath differences in tidal volume seen during control runs with large oscillations present ranged in size from 3.6 to 8.6% of the mean tidal volume. When the oscillations were completely eliminated by means of the mixing chamber the breath by breath differences only ranged from 0.2 to 2.7% of mean tidal volume. The change was highly significant.6. Mean tidal volume and ventilation were not altered by eliminating the large (double period) oscillations.7. It has been shown that the tidal volume is made to change from breath to breath in a persistent manner when there are recurrent changes in carotid arterial blood chemistry. The effects on respiration involve vascular receptors above the mid carotid arterial region. It is argued that the effects involve the sensitivity of the carotid bodies to rapid (within breath) changes in P(a, CO2). There appears to be no significant effect on mean ventilation of the dynamic component of the arterial P(CO2) changes produced in these experiments.

Air↗
PubMed1973

Effect on respiration of changes in the form of the naturally occurring oscillation in arterial pH.

We have previously shorn that the respiratory control system in the cat has the requisite sensitivity and speed to respond to changes in arterial pH which are equal to, or smaller than, the normal fluctuations in pH with respiration. A respiratory response was only observed when the changes in pH were produced by alterations in PCO2 and not when they were induced by non-gaseous acids. We describe now the respiratory effect produced by various procedures which modify or abolish the naturally occurring arterial pH oscillations before they reach the peripheral chemoreceptors. The pH oscillations were abolished by a mixing chamber, whilst their phase relationship to respiration was altered by delay coils; by presenting a moving plastic surface to the arterial blood stream it was possible to distort the shape of the oscillations without increasing the transport lag between lung and peripheral chemoreceptors. All manoeuvres produced a brief period of respiratory stimulation which was greater than could occur by chance. We were particularly concerned in these experiments with the possibility of artefacts in our experimental design. We feel that we have excluded respiratory effects due to changes in arterial pressure, blood temperature and mean pH. We are less confident that we have excluded changes in ventilation resulting from the release of a substance (or substances) from the contact of blood with plastic or glass surfaces. This problem is discussed in relation to experiments on the control of breathing where blood, which is perfusing the chemoreceptors, has been in contact with artificial surfaces.

Animals↗
PubMed1970

Gonorrhoea with skin and joint manifestations.

Three cases of gonorrhoea with pyrexia and lesions of the skin and joints (benign gonococcaemia) seen in one hospital group in 1969 within four months of one another are described. All three patients improved rapidly with penicillin therapy. This syndrome is commoner than is usually thought. It must therefore be borne in mind when a diagnosis is in doubt in a patient with unusual skin lesions and joint involvement. Thorough bacteriological investigation is necessary before starting treatment. The relevant literature is reviewed.

Adult↗
PubMedDate not supplied

Birth weight and smoking practices during pregnancy among Mexican-American women.

The smoking practices of a national sample of Mexican-American mothers and the resulting effects of those practices on birth weight were examined. Data were from the Hispanic Health and Nutrition Examination Survey conducted by the U.S. National Center for Health Statistics during 1983-1984. We found that 24% of the mothers had smoked during their pregnancy, with a mean of 11 cigarettes per day. Infants of these women weighed 101 g less at birth than did infants of nonsmoking mothers and had a low birth weight rate of 8.0% compared with the 5.1% low birth weight rate for the sample as a whole. Multiple regression results indicate a 7.4 g decrease in birth weight for each cigarette smoked per day during pregnancy. Cultural factors that promote a low birth weight rate for Mexican-Americans that is comparable to that of non-Hispanic whites despite increased rates of poverty and inadequate health care do not protect against the insidious effects of cigarette smoking.

Adult↗
PubMedDate not supplied

Ventilation during carbon dioxide loading in anaesthetized women.

The mechanisms whereby arterial carbon dioxide tension (PaCO2) remains constant despite varying rates of CO2 production are poorly understood. During the gynaecological operation of laparoscopy, the abdominal cavity is filled with CO2. An increase in the rate of CO2 delivery to the lung (less than 50%) occurs as a result of venous CO2 absorption. Respiratory control in 39 anaesthetized but spontaneously breathing women was studied during such exogenous CO2 loading. End-tidal CO2 tension (PACO2 - rapid infrared analyser) and minute-ventilation (Wright respirometer) were measured before and at 5 min intervals after peritoneal insufflation. Ventilation increased and mean PACO2 remained constant in these patients. Inhalational anaesthetics depress respiration and this was confirmed by raised control PACO2 values in this study. However, it appears that mechanisms underlying PACO2 homeostasis in the presence of a CO2 load are not depressed by inhalational anaesthetic in this study. These patients were probably hyperoxic. Peripheral arterial chemoreflexes are thought to be eliminated by hyperoxia. Therefore, it is likely that neural stimuli, from exploration of the abdomen, drove breathing. Furthermore, the fact that there was not a large fall in PACO2 may have been due to feedback via the central (brainstem) chemoreceptor.

Anesthesia↗
PubMedDate not supplied

Smoking, acculturation, and pregnancy outcome among Mexican Americans.

The authors present an evaluation of the role of acculturation in smoking practices and pregnancy outcome (N = 767 births) in a national sample of Mexican American women. Data employed are from the 1982-1984 Hispanic Health and Nutrition Examination Survey. The prevalence rates of smoking during pregnancy, low birth weight (< or = 2500 g), and preterm delivery (> or = 3 weeks prior to the expected date) are higher among more acculturated women compared with less acculturated women. Among the more acculturated women, the prevalence of smoking and poor birth outcomes did not increase linearly with increasing American orientation. Rather, women in the third quartile of acculturation scores, i.e., those with a moderate American orientation, experienced significantly poorer birth outcomes than women with either a stronger American orientation or a Mexican orientation. Women at this moderate level of acculturation appear to have the greatest need for public health services rather than women with the lowest level of acculturation (non-English speaking, lowest income) as a means of improving their pregnancy outcomes.

Acculturation↗