Solar heat load: heat balance during exercise in clothed subjects

Summary Six subjects exercised for 60 min on a cycle ergometer. Their backs were exposed to an artificial sun with a spectral distribution similar to sunlight and an intensity of 724 W m^–2. Each subject took part in four experiments in random order: wearing suits of polyester (insulation value = 0.5 clo), white (WP) or black (BP), or cotton (0.6 clo), white (WC) or black (BC). Measured by partitional calorimetry, the calculated heat losses and gains for the four conditions balanced within less than 10%. The differences between the short-wave radiation gains of subjects in white or black garments were small. This is due to the transparency of the white materials, which allows a larger percentage of the radiation to penetrate the clothing. The surface temperatures of the sun-exposed areas were very high, especially in the black suits. This promotes dry heat loss. Therefore the sweat loss in the black suits and the differences between the black and white clothes became relatively small. The physiological strain in steady-state exercise, as expressed by average heart rates, was 142 (WP), 154 (BP), 151 (WC), and 160 (BC) beats min^–1; the sweat losses were 649 (WP), 666 (BP), 704 (WC), and 808 (BC) g. For both of these measures values for white polyester were significantly less than those for black cotton.     

Vitamin B12 and folate status in acute geropsychiatric inpatients: affective and cognitive characteristics of a vitamin nondeficient population

This chart review study examined the serum vitamin B12 and folate status of 102 geriatric patients newly admitted to a private psychiatric hospital. Only 3.7% were B12 deficient and 1.3% were folate deficient; 4% were anemic. Nevertheless, those with below-median values of both vitamins had significantly lower Mini-Mental State scores than patients higher in one or both vitamins. Patients with "organic psychosis" with a negative family history for psychiatric disorder had significantly lower B12 levels than those with a positive family history. In major depression, folate levels correlated negatively with age at onset of psychiatric illness and length of hospitalization. These data suggest that (1) biochemically interrelated vitamins such as B12 and folate may exert both a separate and a concomitant influence on affect and cognition; (2) poorer vitamin status may contribute to certain geropsychiatric disorders that begin at a later age and lack a familial predisposition.     

Precorneal residence time in humans of sodium hyaluronate as measured by gamma scintigraphy

The aim of the present study was to quantify in man the distribution and clearance of two aqueous sodium hyaluronate (SH) solutions of 0.125% and 0.250% after the administration of 25 l onto the cornea. Isotonic phosphate buffer (PB) was used as a reference instillation. No systemic or local medication was given to the seven 18- to 30-year-old, healthy male volunteers. A detailed evaluation of the anterior segment of the eye, as well as a Schirmer test and a break-up time measurement, yielded results within the normal range. The clearance of 0.125% and 0.250% SH solutions radiolabelled with sodium pertechnetate Tc-99m was measured by gamma scintigraphy and compared with that of a PB solution tagged with the same radiolabel. There was no statistically significant difference between the quantities of 0.125% SH and PB solutions remaining in the precorneal space at 20 min (paired t-test,P=0.78,n=7). However, in comparing the 0.250% SH with the PB solution, we observed a statistically significant difference (P=0.01,n=7) in the amount remaining in the precorneal space after the same interval. Actually, 53% of the radiolabelled 0.250% SH solution remained on the cornea as compared with 30% for the 0.125% SH solution and 18.3% for the PB solution. These results suggest that an SH solution of 0.250% might have a prolonged residence time on the precorneal surface, and that SH could therefore be used as an additive in various drug-release systems for the eye.The present work was presented in part at the ARVO annual meeting in Sarasota in 1989     

Neuromuscular and psychomotor abnormalities in patients with schizophrenia and their first-degree relatives

In previous studies of schizophrenic patients, neuromuscular (histopathological and electrophysiological) and psychomotor (finger tapping) abnormalities were found. The present study was designed to investigate relationships between these abnormalities and a family history of psychosis in 14 schizophrenic patients and 25 unaffected first-degree relatives compared to 14 healthy controls. Muscle biopsies were performed in either m. tibialis anterior or m. lateralis. Macro EMG recordings were made from m. tibialis anterior. A finger tapping test was used to investigate psychomotor performance. Neuromuscular abnormalities (muscle biopsies and/or macro EMG) and/or aberrant psychomotor performance (finger tapping test) were found in 13 (93%) patients, 14 (56%) first-degree relatives and in three (21%) controls. A statistically significant relationship for the psychomotor, but not neuromuscular changes to a family history of psychosis was found using a logistic regression method. The percentage of patients, relatives and healthy controls exhibiting were 36/40/7% in the muscle biopsy, 50/20/0% in the macro EMG, and 71/82/14% in the finger tapping investigations. A higher frequency of neuromuscular and psychomotor abnormalities was found in patients with schizophrenia and their first-degree relatives compared to healthy controls. The relationship between psychomotor findings and a family history of psychosis indicate that central aspects of motor aberrations are associated with a hereditary disposition of psychosis. The neuromuscular as well as psychomotor changes indicate that schizophrenia may be a systemic disease involving the central nervous system as well as peripheral organs. An altered cell membrane is suggested to be an underlying factor based on the type of neuromuscular findings.     

Distribution of estramustine in the BT4C rat glioma model

 Estramustine (EaM), a carbamate ester of 17β-estradiol and nor-nitrogen mustard, is a cytotoxic compound with antitumoral effect in malignant glioma in vitro and in vivo . However, knowledge of the pharmacokinetics of EaM in experimental glioma is limited. The objective of this study was therefore to investigate further the distribution of EaM in the BT4C rat glioma model. Assessment of EaM uptake and distribution was performed by quantitative whole-body autoradiography. In addition, the uptake of EaM and its metabolites estromustine (EoM), estradiol, and estrone were analyzed by gas chromatography. EaM was taken up from the circulation and was found to be the main product in glioma tissue. Whole-body autoradiography after [¹⁴C]-EaM administration revealed a strong ¹⁴C label simultaneously in tumor and normal brain tissue at 0.5 h after drug administration. In tumor tissue, sustained high levels of ¹⁴C label were detected at 12 h after drug administration. In contrast to the tumor, radioactivity in normal brain tissue rapidly leveled off, indicating a retention of radioactivity in the tumor. The tumor/brain radioactivity ratio reached a peak of 4.5 at 12 h after drug administration. High levels of ¹⁴C label were also found in pulmonary tissue. By gas chromatography, EoM was found to be the main metabolite in plasma. However, EaM reached higher levels in tumor tissue, with the mean tumor/plasma ratio being 11.7 as compared with 2.0 for EoM. Only low plasma levels of the estrogen metabolites were detected. In conclusion, EaM is taken up in the BT4C rat glioma tissue and is retained in the tumor as compared with normal brain tissue and plasma. EaM showed a greater selectivity for tumor tissue, exhibiting a high tumor/plasma ratio as compared with EoM. The distribution pattern after administration of EaM, as evaluated by both whole-body autoradiography and gas chromatography, supports the earlier suggestion that the uptake is related to a protein with EaM-binding characteristics. Received: 12 January 1997 / Accepted: 28 August 1997     

Phagocytosis and cytokine response to rough and smooth colony variants of Mycobacterium abscessus by human peripheral blood mononuclear cells

Mycobacterium abscessus is a non‐tuberculous mycobacteria able to cause opportunistic infections in selected patient groups. During the last decades it has emerged as a cause of chronic pulmonary infection in patients with cystic fibrosis (CF). M. abscessus strains exhibit either smooth or rough colony morphology. Strains exhibiting the rough phenotype more often cause pulmonary infections in CF patients than did the smooth ones. Here, we examined phagocytosis and production of cytokines by human peripheral blood mononuclear cells, in response to M. abscessus strains with smooth and rough colony phenotype. The rough isolates all formed multicellular cords, similar to what is observed in Mycobacterium tuberculosis. Monocytes were generally unable to internalize these rough cord isolates, in contrast with the smooth ones. Furthermore, the rough M. abscessus strains induced a distinct cytokine profile differing from that induced by the smooth ones. Rough isolates induced significantly less IL‐10 and tumour necrosis factor compared to smooth strains, but more IL‐1β. Both varieties induced equal amounts of IFN‐γ, IL‐17, IL‐23, IL‐6, IL‐8 and equally little IL‐12. The ability to withstand phagocytosis might be a virulence factor contributing to the capacity of rough M. abscessus strains to give persistent pulmonary infections.