Tiliqua scincoides: temperature-sensitive units in lizard brain.

Extracellular action potentials were recorded from units in the preoptic area of the brain of the Australian blue-tongued skink (Tiliqua scincoides) during periods of local heating and cooling of the brain (20 degrees to 36 degrees C) with water-perfused thermodes. In this temperature range most spontaneously firing neurons were temperature-insensitive, but eight showed sensitivity to the thermal stimulus. Five warm neurons increased their activity when the brain temperature was raised, and three cold neurons showed increased activity with fall in temperature.

Visceral tissue vascularization: an adaptive response to high temperature.

Electrical heat sources implanted in the abdominal cavities of sheep were heated to give initial temperatures of 42 degrees and 45 degrees C at the surfaces of the heaters. During 18 days of constant heating, a vascularized connective-tissue envelope encapsulated the heat sources, and the temperatures at the surfaces of the heaters declined 0.8 degrees and 1.8 degrees C, respectively. The degree of vascularization and the magnitude of the decrease in the surface temperature appeared to be related to the proximity of the tissue's initial temperature to 45 degrees C, a temperature ordinarily considered detrimental to cell structure. The vascularization thus appears to be adaptive.

Cord blood thyroxine and thyroid stimulating hormone screening for congenital hypothyroidism: how useful are they?

AIM: To determine and compare the usefulness of cord blood screening for free thyroxine (FT4) and thyroid stimulating hormone (TSH). BACKGROUND: There is a vast amount of literature on capillary heel prick screening tests, but relatively little on cord blood testing particularly FT4. For a decade all infants born at Tawam Hospital had cord blood FT4 and at Oasis Hospital cord TSH measured through the hospital-based screening programme. On January 1st 1998, the national screening programme (NSP) for congenital hypothyroidism (CH) in the United Arab Emirates (UAE) started using capillary TSH measurement (Delfia method). Since then newborns in both hospitals have been screened both ways, i.e. cord blood and capillary blood screening. METHODS: We reviewed retrospectively all infants born from January 1998 until the end of June 2004 with CH who had double screening: cord FT4 or TSH and 4th-5th day TSH screening. RESULTS: Thirteen infants (one in 1,778) had CH in Tawam Hospital. In six of these the cord blood FT4 was low (<9.1 pm/l) (0.73 ng/dl) and in seven the cord blood FT4 was normal, i.e., over half were missed. Eight infants (one in 1,198) had CH in the Oasis Hospital. Cord blood TSH was high in six of them (>13 IU/l) and two were normal. Cord FT4 detected the most severe cases, but missed most others. Cord TSH detected six out of eight cases, but there was a recall rate of one in 23. CONCLUSIONS AND RECOMMENDATIONS: Cord FT4 identifies only infants with severe CH. Cord TSH is more sensitive than cord FT4 screening. Capillary TSH dried blood spot testing on the 3rd-5th day is the most sensitive method.

Pulmonary fungal infection. Survey of 159 cases with surgical implications.

A survey of 159 cases of pulmonary fungal disease treated at the Hospital of the University of Mississippi is presented. The fungal diseases encountered were blastomycosis, 75 cases (47%); histoplasmosis, 38 cases (24%); aspergillosis, 17 cases (11%); cryptococcosis, 13 cases (8%); nocardiosis, nine cases (6%); and actinomycosis, seven cases (4%). Coccidioidomycosis is not endemic to Mississippi. Histoplasmosis was probably more common than diagnosed, but clear cytologic evidence or detection of the organisms was the rigid criterion required for diagnosis. Immunosuppressed patients appeared to be especially susceptible to infection by certain of the fungi. Fungal diseases were found to mimic numerous other pulmonary lesions, and specific diagnosis was often long delayed. Seventy-one operations were required for diagnosis or therapy or both, with two deaths. The major pulmonary complications of the several fungal diseases have been reviewed. Pulmonary hemorrhage constituted the major emergency. Amphotericin B was the mainstay of drug therapy, but upon occasion stilbamidine, penicillin, sulfonamides, and other agents were useful in specific circumstances. Accurate diagnosis, appropriate drug therapy, and judicious operative intervention when required will achieve gratifying clinical results in the vast majority of pulmonary fungal diseases.

The destruction of type 2 pneumocytes by airborne influenza PR8-A virus; its effect on surfactant and lecithin content of the pneumonic lesions of mice.

Influenzal pneumonia has been studied in mice subjected to sublethal doses of airborne PR8-A influenza virus. Electron microscopy revealed that the virus propagated in and at the same time destroyed the ciliated and nonciliated bronchial cells and the types 1 and 2 alveolar pneumocytes. The regenerating bronchial membranes were metaplastic and grew peripherally into the surrounding alveolar ducts and alveoli to form epithelial nodules which caused obstruction and collapse of the involved lobes. The development of the lung lesions was correlated with phospholipid (lecithin) levels in consolidated and unconsolidated infected and normal lungs. As the lungs became more and more consolidated, there was a corresponding and significant decrease in the amount of phospholipid (dipalmitoyl lecithin) compared to the amount of normal or unconsolidated infected tissue. The destruction of the type 2 pneumocytes by the influenza virus and their failure to regenerate is considered to be the reason for the low phospholipid levels in the involved lobes, and thus an important cause of post-influenzal collapse in mice. The above adds additional evidence to the view that the type 2 pneumocytes are a major source of surfactant in mammalian lungs.

Successful orthotopic allotransplantation of hearts from dogs in irreversible shock.

The viability of the heart from irreversibly shocked dogs was evaluated. Thirty-one mongrel dogs were used to develop a uniformly lethal hemorrhagic shock model. The final model utilized a 30 mm. Hg mean arterial pressure with a 40 percent decompensation (uptake of reservoir blood). All control dogs subjected to this procedure died within 24 hours. Eleven hearts were transplanted following the shock procedure. Blood samples were drawn at intervals and analyzed for Po2, pH, glucose, oxygen content, and hematocrit. Cardiac outputs and ECG's were taken before and after transplant. All parameters measured returned to control levels following the transplants. Of the dogs receiving heart transplants, 10 survived more than 24 hours and eight survived more than 7 days. Compared with the survival of the shock model experiments, the survival of the transplant recipients was significant at the p less than 0.01 level. These results suggest that deterioration of the heart is not the factor which prevents recovery from irreversible hemorrhagic shock.

Long-term memory for contextual attributes: dissociation of amygdala and hippocampus.

Rats were given passive avoidance training within a distinctive environment followed by subseizure level stimulation of the hippocampus or amygdala. The animals were then tested for retention of the aversive experience using a partial cue (subset of the original training environment) and a complete cue (the original training environment). Post-trial hippocampus stimulation produced a retention deficit in both the partial and complete cueing conditions, while post-trial amygdala stimulation produced an intermediate retention deficit in the partial, but no deficit in the complete cueing condition. It is proposed that the hippocampus, but not the amygdala, is involved in processing of the environmental context utilizing spatial temporal attributes.

Cynical hostility and vulnerability to disease: social support, life stress, and physiological response to conflict.

Previous research has indicated that high scores on the Cook and Medley Hostility (Ho) scale are associated with increased risk of coronary heart disease and other illness. Our study attempts to clarify this relationship by providing additional evidence concerning the construct assessed by the Ho scale, examining the level of physiological reactivity during interpersonal conflict in high- and low-Ho groups, and assessing the psychosocial profile associated with this characteristic. Extremely high and low Ho groups were selected from a pool of male undergraduates. Consistent with previous findings, high-Ho participants reported greater anger proneness and a more cynical, disparaging view of others than did low-Ho participants. The high-Ho group also tended to be more hostile and less friendly during role-played interactions involving high and low levels of interpersonal conflict, respectively. High-Ho persons also displayed greater diastolic blood pressure reactivity during interpersonal conflict. Finally, the high-Ho group reported less social support and more negative life events and daily irritants then did the low-Ho group. These results support the interpretation of the Ho scale as a measure of cynical hostility and are consistent with the hypothesis that it is related to disease by way of excessive physiological reactivity and a generally stressful, unsupportive social network.

What of the next 25 years?

The early history of the Society for Surgery of the Alimentary Tract has been reviewed, and the remarkable progress in gastrointestinal surgery over the first 25 years of its existence has been acknowledged. The challenging dimensions of the problems that remain unsolved have been emphasized, and the directions that fruitful research may take in the next quarter century have been suggested. The alimentary tract surgeon will be called upon to adapt to change, and to move into new fields of clinical physiology and surgery. The discoveries and progress to be anticipated in the years to come are vast.

Technical options in venous valve reconstruction.

PURPOSE: Several modifications and details of techniques that were found useful in venous valve reconstruction are described. Related technical outcome data are also presented. METHODS: Five hundred eighty-two valve segments were reconstructed in 347 limbs using a variety of different techniques. RESULTS: Intraoperative valve competence was achieved in 86% of 347 limbs. The incidence of technical stenosis was 4%, thrombosis of repair <1%, loss due to hematoma/infection <1%, and operative mortality 0%. Postoperative duplex competence was achieved fully in 78% and partially in 16%; 6% remained refluxive. Rapid postoperative healing of stasis ulcer occurred in 93%. CONCLUSIONS: The expanded variety of technical options in valve reconstruction allows optimization for the individual patient. Regardless of pathology, a functional venous valve can be reconstructed in most patients utilizing one of the described techniques.

Hemorrhagic shock in dogs. Comparison of treatment with shed blood alone versus shed blood plus Ringer's lactate: intravascular pressures, cardiac output, oxygen consumption, arteriovenous oxygen differences, extracellular fluid PO2, electrolyte changes, and survival rates.

The purpose of our study of hemorrhagic shock in dogs was to examine the efficacy of adding Ringer's lactate to shed blood replacement in increasing animal rates. The standard Wiggers' hemorrhagic shock technic was used in two groups of ten animals each. Intravascular pressures, cardiac outut, oxygen consumption, arteriovenous oxygen differences, extracellular fluid PO2 and pH, electrolyte changes, and survival rates were determined. There was a positive correlation between changes in cardiac output, central venous oxygen content, and PO2 and extracellular fluid PO2 as measured using subcutaneously implanted Silastic tubing and perforated plastic balls. Four of the dogs that received shed blood alone survived, whereas five of the dogs that received shed blood plus Ringer's lactate survived. This difference was not statistically significant.

Phencyclidine and behavior: II. Active avoidance learning and radial arm maze performance.

Rats with injections of 4 or 8 mg/kg of phencyclidine (PCP) are impaired in the acquisition of active avoidance learning and radial arm maze performance. This impairment was not due to a change in detectability of aversive stimuli or the inability to perform the correct response. The primary deficit appears to be the inability of PCP injected animals to encode the appropriate attributes (e.g., environmental context, response selection, and emotion) associated with each task.

Phencyclidine and behavior: I. Sensory-motor function, activity level, taste aversion and water intake.

Phencyclidine (PCP) injections in rats at doses of 4 mg/kh increased activity level, which might have been a function of impaired habituation. At doses of 8 mg/kg PCP produced a marked reduction in activity level. At doses of 12 mg/kg and above there were profound disruptive effects in detection of odors, visual square and touch measures, and performance of placing reflexes requiring visuo-motor coordination, righting, grasping reflexes, and equilibrium. Decreases in water intake occurred only at higher dose levels of PCP (16 and 24 mg/kg). On a qualitative basis the changes observed in rats are similar to changes described for humans.

Atrial natriuretic factor (ANF): a preliminary report of cervical heart transplant model for study.

The allograft canine heart transplanted to the neck of a recipient provides a useful model for direct measurement of atrionatriuretic factor (ANF) in the single inflow artery and the single outflow vein (pulmonary artery). The normal peripheral blood levels of ANF in the dog ranged from 25-77 pg/ml, whereas the post-transplant level in transplant outflow blood was 2262 pg/ml 30 minutes after transplant resuscitation. The cervical heart transplant model is applicable to a variety of ANF investigations.

Epithelial and surfactant changes in influenzal pulmonary lesions.

Pulmonary epithelial cell destruction in mice infected with PR8-A influenza virus has been studied with light and electron microscopy and enzyme histochemistry, and correlated with pulmonary surfactant activity. All epithelial cell types were infected by the virus, resulting in destruction, pneumonitis, and atelectasis by seven to ten days. Pulmonary surfactant activity decreased progressively following onset of infection, and was minimal by seven to ten days. Before types 1 and 2 alveolar pneumocytes regenerated, the regenerating bronchial cells grew peripherally into some of the denuded alveolar ducts and alveoli to form epithelial nodules. Eventually the types 1 and 2 pneumocytes regenerated to cover the alveolar surfaces that were not invaded by bronchial epithelium. This regeneration was associated with increased surfactant activity in the postinfluenzal lesions, suggesting that the type 2 pneumocytes are a source of surfactant.