Ten-year stability of cardiovascular responses to laboratory stressors

In this study we examined test-retest stability of cardiovascular stress responses over a decade of the life span. Participants were 55 male college undergraduates. 19 years of age at initial testing, and 29 years of age at follow-up testing Stressors were a foot cold pressor and an aversive reaction time task. Cardiovascular measures included systolic and diastolic blood pressure, heart rate, and preejection period. For cold pressor, the magnitude and pattern of cardiovascular responses remained unchanged at the 10-year follow-up. For the reaction time task, the characteristic cardiovascular response patterns was preserved but with significant attenuation of magnitude. The present findings are consistent with previous observations of temporal stability but over a substantially longer test-retest interval. The long-term stability of stress responses is discussed in the context of stress test methodology, behavioral response demands, and maturation of the physiological systems involved in cardiovascular response expression.     

A simple in vitro model for investigating epithelial/mesenchymal interactions: keratinocyte inhibition of fibroblast proliferation and fibronectin synthesis

Hypertrophic scarring and graft contracture are major causes of morbidity after burn injuries. It is well established that application of a split-thickness skin graft reduces scarring and contraction, and cultured epithelial autografts have a similar effect. To investigate the influence of keratinocytes on fibroblast proliferation and fibronectin synthesis, we used an in vitro separated co-culture model in which epithelial sheets were cultured above fibroblast monolayers without physical contact. We also investigated the response of fibroblasts to keratinocyte-conditioned medium (KCM) obtained from confluent and subconfluent keratinocyte monolayers. Both cultured epithelial sheets, composed of adherent fully confluent keratinocytes, and their conditioned medium, reduced fibroblast proliferation. However, KCM from subconfluent keratinocytes stimulated fibroblast proliferation at low concentrations while inhibiting it at higher concentrations, indicating that keratinocytes can produce both mitogenic and growth-inhibiting factors for fibroblasts. KCM, but not epithelial sheet co-culture, also inhibited fibroblast fibronectin synthesis. This indicates regulation of fibroblast phenotype by soluble factors released by the keratinocyte and also suggests that there is a dialogue between keratinocytes and fibroblasts with respect to fibronectin production. We conclude that this separated co-culture model is a simple way to study epithelial/mesenchymal communication particularly with respect to the role of the fibroblast in wound healing.     

THE EFFECTS OF 6-HYDROXYDOPAMINE OR (–)-NORADRENALINE TREATMENT IN VITRO ON NORADRENERGIC TRANSMISSION IN THE RAT ANOCOCCYGEUS MUSCLE

• 1 The effects of 6-hydroxydopamine treatment in vitro for varying times on the overflow of ³H (following preloading of the tissue with (–)-[³H]-noradrenaline) and the accumulation of ³H from (–)-[³H]-noradrenaline have been investigated in the rat anococcygeus muscle. In addition the effects on contractile responses to field stimulation and to other stimulants are reported.
• 2 Following preloading of the rat anococcygeus muscle with 5 times 10^-7M (–)-[³H]-noradrenaline for 1 h, the overflow of ³H was increased by 6-hydroxydopamine (1 times 10^–3M). At the end of the overflow period the tissue content of ³H was reduced by 95% from tissues treated with 6-hydroxydopamine for ≥ 30 min. The rat anococcygeus muscle accumulated ³H from a medium containing 5 times 10^–8M (–)-[³H]-noradrenaline. The ability to accumulate ³H was reduced after incubation in 6-hydroxydopamine for 5 min and abolished by longer incubations. These effects of 6-hydroxydopamine probably represent depletion of endogenous (–)-noradrenaline stores and destruction of noradrenergic neurones.
• 3 6-Hydroxydopamine induced contractions of the rat anococcygeus that were abolished by phentolamine (1 times 10^-6M).
• 4 The excitatory contractile responses to field stimulation were reduced after exposure to 6-hydroxy-dopamine for 5 min and were abolished after longer exposures. 6-Hydroxydopamine had no effect on the inhibitory response to field stimulation. The contractile responses to (–)-noradrenaline were potentiated after 6-hydroxydopamine.
• 5 Following 6-hydroxydopamine treatment for 5 min the responses to tyramine were potentiated. This potentiation was probably due to the release of endogenous (–)-noradrenaline. The responses to tyramine were reduced after longer treatments (30–120 min).
• 6 Short incubations of the anococcygeus muscle with 6-hydroxydopamine or (–)-noradrenaline had no effect on the subsequent responses to acetylcholine whereas after a 180 min treatment the responses were reduced. This effect was possibly due to fatigue of the muscle. Incubations with (–)-noradrenaline for 60 min had no effect on the responses to field stimulation or to (–)-noradrenaline. After longer pretreatments the responses were reduced. Thus after long exposures to (–)-noradrenaline, and probably to 6-hydroxy-dopamine, responses may be reduced by fatigue or by desensitization at α-adrenoreceptors. 7 These results suggest that, in the rat anococcygeus muscle, a selective abolition of noradrenergic transmission was obtained by treating the tissue with 6-hydroxydopamine for 30–60 min. The contractile responses to tyramine in this tissue may, in part, be due to a direct postjunctional action.

     

Implementation of a Multidisciplinary Inpatient Cardiology Service to Improve Heart Failure Outcomes in Guyana

Background

Guyana is a small developing country with a high burden of cardiovascular disease and extensive barriers to optimal care delivery. We investigated the effectiveness of a newly established multidisciplinary inpatient cardiology service in this setting.

The Relation Between Breastfeeding and Amenorrhea: Report of a Survey

Nursing mothers completed questionnaires concerning various breastfeeding practices. First, those questionnaires lacking sufficient data were eliminated; then two more samplings were made, one of mothers who fed exclusively by breast for at least 5 months and the other of mothers who met the criteria for complete "natural mothering." Each sample was analyzed according to duration of breastfeeding and duration of amenorrhea, and the findings were compared. The all-inclusive sample averaged 10.2 months of amenorrhea; the sample of mothers who fed exclusively by breast, 11.6 months; the natural mothering sample, 14.6 months. The authors compared their results with those of other studies and concluded that breastfeeding, lactation amenorrhea and the resulting extended postpartum infertility comprise a delicate symbiotic relationship involving the ecologic interdependence of mother and child.(An extension of the conclusion is offered: the right of nursing mothers to know how certain cultural practices can upset such an ecology.)     

Iron Deficiency and Autoimmunity in Post-cricoid Webs

The incidence of post-cricoid webs in patients with iron-deficiencyanaemia and a variety of other conditions including thyroiddisease, pernicious anaemia, ulcerative colitis, and Sjögren'ssyndrome has been examined by cinefluorography of swallowing.A total of 32 subjects were found to have a post-cricoid web;17 of these were patients in whom the index diagnosis was irondeficiency. One or more subjects in each of the other groupsstudied were found to have a post-cricoid web, but webs werenot seen in a healthy control group. Definite evidence of iron deficiency either at the time of diagnosisof the web or in the past was obtained in all but five of the32 patients with a post-cricoid web. Clinical and laboratoryfindings in these 32 patients were combined with results inour 72 patients with webs described previously and comparedwith the findings in two control groups. There was a significantincrease in the incidence of angular stomatitis, glossitis,edentia, thyroid disease, and thyroid antibodies in patientswith a post-cricoid web when compared with an iron-deficientcontrol group without a web. A high incidence of malignant diseaseof the upper gastrointestinal tract was also found in patientswith webs. The incidence of gastric parietal cell antibodies was significantlyhigher in patients with iron deficiency, irrespective of thepresence of a web, than in the healthy controls. The role of iron deficiency and autoimmunity in the pathogenesisof post-cricoid webs and the other tissue changes associatedwith iron deficiency is discussed.     

Studies on the Serology of Paroxysmal Cold Haemoglobinuria (P.C.H.), with Special Reference to its Relationship with the P Blood Group System

Les auteurs ont testé la spécificité de 11 sérums d'hémoglobinurie paroxystique a frigore. Ces sérums ont hémolyse les globules rouges P₁ et P₂, mais n'ont pas réagi avec les hématies p ou P^k, ce qui suggère une spécificité semblable à celle d'un anti-P présent dans le sérum des sujets P^k. L'anticorps n'est pas inhibé par le liquide de kyste hydatique à la dilution de 1/40 et son effet n'est pas renforcé par un traitement enzymatique des hématies. L'hémolyse n'est que légèrement supérieure avec des globules rouges d'hémoglobinurie nocturne paroxystique.

Zusammenfassung

Bei 11 P.C.H.-Seren wurde die P-Spezifität untersucht. Die Seren reagierten mit P₁ und P₂-Zellen, nicht aber mit p- oder P^k-Zellen. Dies deutet auf eine Spezifität hin, welche derjenigen der Anti-P-Antikorper bei P^k-Individuen weitgehend entspricht. Der Antikörper wurde durch Hydatidenzystenfiüssigkeit in der Verdünnung 1:40 nicht gehemmt. Ebensowenig wurde eine Verstärkung der Reaktionen durch Enzymbehandlung der Zellen beobachtet. Die Verwendung von P.N.H.-Zellen bewirkt nur eine geringfügige Zunahme der Lyse.     

Cervical Cytology Screening Convenient for the Workforce

The study describes the demographic details and smear resultsof women attending a Well Woman Clinic in an Occupational Healthsetting over a two year period. The clinic is located closeto the place of work, run during working hours, and operatedby a doctor and nurse. Charging fees acceptable to women attending or their employers,the service has made a modest profit and offers scope for increasingthe income against fixed costs. The age range attending is older than commonly found at screeningclinics. The abnormal smear detection rate, 115 per 1000 ishigh while the proportion of inadequate results at 50 per 1000compares favourably with other clinics. In an area with 13 percent Asian population, only 5 per cent of attenders were Asianbut of these one fifth had abnormal smears. A cervical cytology screening facility timed and located forthe convenience of the working woman is found to attract a groupof women in the older age range who have a high abnormal smearrate, and those who fail to attend elsewhere. Requests for reprints should be addressed to: Sheila M. Andren, 121 Gresham Road, Staines, Middlesex TW18 2AJ, UK